Cooldown of Products after Cooking

Cooldown of Products after Cooking
Eben van Tonder
17 February 2022


I am part of a team designing a meat processing factory in Lagos, Nigeria. I considered refrigeration from the standpoint of the effect of long term storage on product quality. In 2018 I did a comprehensive survey of The Freezing and Storage of Meat. I looked at weight loss during chilling and storage of meat. In 2019 I looked at Weight Loss During Chilling and Freezing of Meat. This time, the issue at hand is rapid cooling after cooking. Home Production of Quality Meats and Sausages by John Novak provided great introductory comments and he was kind enough to mail me the relevant chapter of his book.

He summarises the important point as follows: “Cooling down of cooked products is basically done to cross the danger zone (140o – 40oF; 60oC – 4oC) relatively fast. Cooked sausage at 160oF (72oC) so is still basically safe until the temperature drops down to about 60oC. Therefore, the restaurants are required to hold hot food at 140o F (60oC) or higher.” (Novak)

Regulatory Standard and Application

“The following standards come from the Food Safety and Inspection Service (FSIS), United States Department of Agriculture (USDA):

Compliance Guidelines for Cooling Heat-Treated Meat and Poultry Products (Stabilization)

It is very important that cooling be continuous through the given time/temperature control points. Excessive dwell time in the range of 130°F (55oC) to 80°F (27oC) is especially hazardous, as this is the range of most rapid growth for the clostridia. Therefore cooling between these temperature control points should be as rapid as possible.

1. During cooling, the product’s maximum internal temperature should not remain between 130°F (55oC) and 80°F (27oC) for more than 1.5 hours nor between 80°F (27oC) and 40°F (4oC) for more than 5 hours. This cooling rate can be applied universally to cooked products (e.g., partially cooked or fully cooked, intact or non-intact, meat or poultry) and is preferable to (2) below.

2. Over the past several years, FSIS has allowed products to be cooled according to the following procedures, which are based upon older, less precise data: chilling should begin within 90 minutes after the cooking cycle is completed. All products should be chilled from 120°F (48°C) to 55°F (12.7°C) in no more than 6 hours. Chilling should then continue until the product reaches 40°F (4.4°C); the product should not be shipped until it reaches 40°F (4.4°C). This second cooling guideline is taken from the former (“Requirements for the production of cooked beef, roast beef, and cooked corned beef”, 9 CFR 318.17(h)(10). It yields a significantly smaller margin of safety than the first cooling guideline above, especially if the product cooled is a non-intact product.

If an establishment uses this older cooling guideline, it should ensure that cooling is as rapid as possible, especially between 120°F (48°C) and 80°F (27oC), and monitor the cooling closely to prevent deviation. If product remains between 120°F (48°C) and 80°F (27oC) for more than one hour, compliance with the performance standard is less certain.

3. The following process may be used for the slow cooling of ready-to-eat meat and poultry cured with nitrite. Products cured with a minimum of 100 ppm ingoing sodium nitrite may be cooled so that the maximum internal temperature is reduced from 130 to 80° F in 5 hours and from 80 to 45° F in 10 hours (15 hours total cooling time).

This cooling process provides a narrow margin of safety. If a cooling deviation occurs, an establishment should assume that their process has exceeded the performance standard for controlling the growth of Clostridium perfringens and take corrective action. The presence of the nitrite, however, should ensure compliance with the performance standard for Clostridium botulinum.

From FSIS Directive 7117.0

1. Heat-resistant food-poisoning bacteria can grow from 38°F 3oC up to approximately 125°F (49oF); however their range of rapid growth is from approximately 80°F to 125° F. Thus, cooling product quickly through the rapid growth range is more important than cooling through the slow growth range.

2. The rate of heat transfer (cooling rate) from the product’s centre to its surface is directly proportional to the difference in temperature between those two points. Thus, as the product temperature approaches the coolant temperature, the cooling rate diminishes.

3. Traditional cured products, containing high amounts of salt and nitrite, together with low moisture content are more resistant to bacterial growth than similar newer products; some are even shelf-stable. Thus, rapid cooling of these traditional products is not always necessary. However, manufacturers are making fewer products of this type today. Instead, to meet present consumer tastes, most of their cured products contain less salt and more moisture. These changes minimize the inhibitory effect of added nitrite and increase the need to rapidly cool these products.” (Novak)

Water Cooling

The best way to cool sausages down is with water. Showering with cold water is a technique universally used. “Water removes heat much faster than air and hot products will drop their temperature fast. If a product was smoked such showering also cleans the surface of any remaining smoke particles and prevents shrivelling.” (Novak)

Let’s delve deeper into the science behind cooling. To do this we use Watts per meter-Kelvin (W/mK) or what is known as the ‘k Value’. It is the measure used to compare thermal conductivity. The k value, or Thermal Conductivity, is the rate of heat transfer in a homogeneous material. A k value of 1 means that 1m cube of a material will transfer heat at a rate of 1 watt for every degree of temperature difference between opposite faces. This will be given as 1 W/mK. The lower this value is, the less heat the material will transfer.

Chris and Steve James point out that “the thermal conductivity of processed meat products (including cured sausages and hams) range between 0.272 Wm-1K-1 at 22°C to 0.482 Wm-1K-1 at 80°C (Marcotte et al., 2008), whereas the thermal conductivity of water is 1 Wm-1K-1. Thus, the thermal conductivity of water is more than double that of most processed meats.”  Water sprayed onto the surface of a food product will act as a high conductivity path. 

Intermitted Spray Cooling

Chris and Steve James made their comments on a blog site related to intermitted spray cooling in response to someone claiming that water on the surface of a product acts as an insulator which is obviously incorrect not the case, as one can see when comparing the K value of the sausages and that of water. They stated that “the reason why intermittent spray cooling can have benefits over continuous spray cooling is that a break in spraying allows the water on the surface of the hot product to evaporate, thus enhancing the cooling effect.”

Panão (2008) investigated the physics involved in the heat transfer process using intermitted spray cooling. Their work has shown that small duty cycles promote heat removal by phase-change. They found that “as the duty cycle evolves toward the continuous spray condition, the cooling system’s thermal response improves, but phase-change is mitigated, affecting the system’s performance. Intermittent spray cooling is also compared with continuous spray cooling experiments and liquid savings has been estimated by 10–90% for the same energetic efficiencies reported in the literature.” They further recommend using shorter impingement distances and low injection pressures. (Panão, 2008)

Craig Habbick who has experience with these systems recommends the following procedure. Brine solution (water and salt) cooled to -5oC and sprayed intermittently altering 2 minutes to 1 minute off with circulation on during the spray off times. The entire cycle takes 15 minutes and reduces core temperature from 72oC to 2oC.

The concentration of salt was high. They used a Baume meter regulator to test the salt. Weight loss was so low that they had to remove water from the recipe due to seepage in the packs after packaging. Nett loss during cool down was around 2%. They used an Alkar brine chiller.

For details on the Alkar Brine Chiller, visit

The important graphs from the Alkar website are:


Novac remarks that there is no need to grab a water hose the moment the sausage was cooked in a smokehouse to 155° F (69°C) as this temperature lies outside the danger zone (40 – 140°F, 4 – 60°C). “U.S. regulations permit restaurants to hold cooked food at 145°F (63°C) or higher temperatures. However, once when the temperature of the product drops to 140°F (60°C), it should be cooled fast. The surface of a product such as a head cheese or smoked sausage both will benefit from a brief hot shower or immersing them in hot water. This will remove any possible grease from the outside and the product will look better. Then it will be showered with cold water. Some pork products may be cooked to > 137° F (58°C) just to eliminate the danger of contracting Trichinae. Such products should be cold showered immediately as they are already lying within the danger zone.” (3. Traditional cured products, containing high amounts of salt and nitrite, together with low moisture content are more resistant to bacterial growth than similar newer products; some are even shelf-stable. Thus, rapid cooling of these traditional products is not always necessary. However, manufacturers are making fewer products of this type today. Instead, to meet present consumer tastes, most of their cured products contain less salt and more moisture. These changes minimize the inhibitory effect of added nitrite and increase the need to rapidly cool these products.” (Novak)

Blast Chiller

We initially planned to have a blast chiller, but after the recommendation from Craig Habbick, the intermitted spray cooling system is so effective that there is no need for an air chiller (blast chiller).

Further Reading

The Alkar product Brochure


Jensen, W. K., Devine, C., Dikeman, M. (Editors), (2014), Encyclopedia of Meat Sciences, Second Edition. ISBN: 9780123847317. Elsevier.

Marcotte, M., Taherian, A. R. & Karimi, Y. (2008) Thermophysical properties of processed meat and poultry products.  Journal of Food Engineering. Vol. 88:3, pp315-322

Miguel R.O. Panão, António L.N. Moreira, Intermittent spray cooling: A new technology for controlling surface temperature, International Journal of Heat and Fluid Flow, Volume 30, Issue 1, 2009, Pages 117-130, ISSN 0142-727X,

Novak, J. Home Production of Quality Meats and Sausages

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Collagen, Reticular and Elastic: A Closer Look

Collagen, Reticular and Elastic: A Closer Look
17 January 2022
Eben van Tonder

Dedicated to Dawie and Zelda


I’ve been working with animal parts high in collagen for the last few years, being bones, skin, tendons and organs. It is part of broader work aimed at using the complete animal and by-products for human food and animal feed, respectively. On the plant matter side, similar work is undertaken to use the entire plant to eliminate waste and achieve greater bioavailability from both for its functional role in food ingredients perspective as well as nutrition.

On 6 to 9 January 2022, I had an extremely productive weekend with Dawie Hyman and his twin sister Zelda at Boggomsbaai on the South African southern Cape coast. Inspired by them I decided to take a closer look at collagen to continue my investigation of skin/ hide/ tendons for an increased role in providing structure in Frankfurter style sausages both hot and cold. I dedicate this set of personal notes to Dawie and Zelda for their inspiration, motivation, and great friendship.

The structure of my investigation is based on the Ushiki (2002). These are my private notes to review the available scientific data which invariably leads to an application in food processing. I have been challenged to look at the role of collagen networks in providing structural support.

The overview of a few key papers written on the subject of extracellular networks and reviewing how collagen strands are formed in vitro and how the casings industry process collagen into edible casings, provided me with a completely new set of tools for further investigation into manipulating

One of my projects for 2022 will be focused on a production facility being set up in West Africa. Being back in such an environment is very exciting for me because it allows the slow progression of existing methods as opposed to the relentless pressure of a purely R&D environment where there is often unrealistic expectation of progress that must be turned into profit for the project to continue. I have been in such an environment for almost two years now. In contrast to this, a traditional meat processing plant’s first priority is to stick to time tested processes and incremental, almost unnoticeable changes. The relentless nature of the R&D environment taught me much and provided a firm basis for future work, but I believe this to be best done in a factory environment where such work is no more than 10% of daily tasks, giving ample time for careful thought and theoretical work before progressions are attempted.

When I had the opportunity to re-look the matter of bacon production, it was done in such an environment at Woodys Consumer Brands. Best Bacon and Rib System on Earth developed from this.

Apart from my own conclusions, reviewing the structures under discussion is rewarding, enriching and by itself provides great insight into the work of the meat/ plant processor. I prefer giving the interesting sections by quoting the authors verbatim allowing me the luxury of reviewing their work from time to time and discovering new elements for application that I have previously missed.

Philosophically, the work is very important to me as it goes to a fundamental requirement I have in meat and plant processing that it must be done with great respect as it involves the ending of life for the sake of survival. This is more obviously related to animals, but it is a faulty perspective that causes us not to see plants in the same light. Waste is an act of disrespect. Animal and plant waste is at the heart, I believe, of mainly Western disease. I made it a mission to investigate the entire animal carcass and the entire plant and find the great value that nature bestowed on every part of the animal and plant.

With these preliminary thoughts, let’s delve into the subject.

A. Relook at Collagen

Previous notes on collagen and gelatin I made are:

Collagen Marker: Hydroxyproline

Functional Value of Gelatin

Notes on Collagen

I looked at unprocessed beef tendons for inclusion in recipes:

Regarding Meals with Beef Tendons

Every application is in-line with the landmark work on meat emulsions which I feature in: Review of comminuted and cooked meat product properties from a sol, gel and polymer viewpoint

Most of the experimental work was done where I also considered Cell Disruption Technology:

The End of the Rendering Plant

The Power of Microparticles: Disruptor (DCD) Technology


“Collagen fibres present a cord- or tape-shaped 1-20 μm [10-6; millionth] wide and run a wavy course in tissues. These fibres consist of closely packed thin collagen fibrils (30-100 nm [10-9; billionth] thick in ordinary tissues of mammals), and exhibit splitting and joining in altering the number of the fibrils to form a three-dimensional network. Individual collagen fibrils (i.e., unit fibrils) in collagen fibres have a characteristic D-banding pattern whose length ranges from 64 to 67 nm [10-9; billionth], depending on tissues and organs. During fibrogenesis (mechanism of wound healing and repair), collagen fibrils are considered to be produced by fusing short and thin fibrils with tapered ends.” (Ushiki, 2002)

In vertebrates, there are 28 collagen types, and these are classified “according to domain structure, function and supramolecular assembly [for a review, see Mienaltowskiand Birk (2014)]. The most abundant are the fibrillar collagens that form the basis of the fibrils in bony, cartilaginous,fibrous and tubular structures.” (Kadler, 2017)

“Collagen fibrils are complex macromolecular assemblies that comprise different fibrillar collagen types (Hansen &Bruckner 2003). The fibrils are either ‘predominately type I collagen’ or ‘predominately type II collagen’. Predominatelytype I collagen fibrils occur in bony, tubular and fibrous tissues, whereas cartilaginous tissues contain predominately type II collagen fibrils. Collagen fibrils range in length from a few microns to centimetres (Craiget al.1989) and therefore have molecular weights in the tera Dalton range [based on calculations described by Chapman (1989)]. The fibrils provide attachment sites for a broad range of macro-molecules including fibronectin, proteoglycans and cell surface receptors such as integrins, discoidin domain-containing receptors and mannose receptors (Di Lulloet al.2002; Joki-nenet al.2004; Sweeneyet al.2008; Orgelet al.2011). Furthermore, the fibrils vary in diameter depending on species, tissue and stage of development (Parryet al.1978;Craiget al.1989) and in response to injury and repair (Pin-gelet al. 2014). Collagen fibrils are arranged in exquisite three-dimensional architectures in vivo including parallel bundles in tendon and ligament, orthogonal lattices in cornea, concentric weaves in bone and blood vessels and basketweaves in skin.” (Kadelr, 2017)

Reticular Fibres

“Reticular fibers are usually observed as a delicate meshwork of fine fibrils stained black by the silver impregnation method. They usually underlie the epithelium.” (Ushiki, 2002) “The epithelium is a type of body tissue that forms the covering on all internal and external surfaces of your body, lines body cavities and hollow organs and is the major tissue in glands.” (Cleveland Clinic)

“Epithelial tissue has a variety of functions depending on where it’s located in your body, including protection, secretion and absorption.

The organs in your body are composed of four basic types of tissue, including:

  • Epithelial.
  • Connective.
  • Muscular.
  • Nervous.

All substances that enter or leave an organ must cross the epithelial tissue first.

You have many different kinds of epithelial tissue throughout your body. Some examples of epithelial tissue include:

  • The outer layer of your skin (epidermis).
  • The lining of your intestines.
  • The lining of your respiratory tract.
  • The lining of your abdominal cavity.
  • Your sweat glands.”

(Cleveland Clinic)

Reticular fibres “cover the surface of such cells of muscle cells, adipose cells or fat cells, connective-tissue cells specialized to synthesize and contain large globules of fat and Schwann cells which are the main glial cells of the peripheral nervous system which wrap around axons of motor and sensory neurons to form the myelin sheath. “Electron-microscopically, reticular fibres are observed as individual collagen fibrils or a small bundle of the fibrils, although the diameter of the fibrils is thin (about 30 nm [10-9; billionth]) and uniform. Reticular fibres are continuous with collagen fibres through the exchange of these collagen fibrils. In silver-impregnated specimens, individual fibrils in reticular fibres are densely coated with coarse metal particles, probably due to the high content of glycoproteins around the fibrils.” (Ushiki, 2002)

Elastic Fibres

“Elastic fibres and laminae (a thin layer or scale of organic tissue) are composed of micro-fibrils and elastin components. Observations of the extracted elastin have revealed that elastin components are comprised of elastin fibrils about 0.1-0.2 μm [10-6; millionth] thick. Elastic fibres and laminae are continuous with networks and/or bundles of microfibrils (or oxytalan fibres) and form an elastic network specific to individual tissues.” (Ushiki, 2002)

Two Systems but Three Types

> Two Systems

“The fibrous components of the extracellular matrix are thereby morphologically categorized into two systems: 

a. the collagen fibrillar system (constituents of tendons) as a supporting framework of tissues and cells, and

b. the microfibril-elastin system for uniformly distributing stress to maintain the resilience adapted to local tissue requirements.” (Ushiki, 2002) “Fibrillin microfibrils are extensible polymers that endow connective tissues with long-range elasticity and have widespread distributions in both elastic and non-elastic tissues. They act as a template for elastin deposition during elastic fibre formation and are essential for maintaining the integrity of tissues such as blood vessels, lung, skin and ocular ligaments.” (Thomson, 2019)

> Three Types of Fibres

“Fibrous components of the extracellular matrix are classically divided into three types of fibres: collagen, reticular and elastic. This classification is based on the light microscopic findings (e.g., their shapes, staining properties and arrangements) and chemical properties of these fibres (e.g., MALL, 1896; FOOT, 1928; HAS, 1942); collagen fibres appear as thick and wavy strands stained pink with eosin, while reticular fibres are fine fibres stained dark with the silver impregnation method. Elastic fibres, on the other hand, are observed as a cord or sheet stained purple with resorcin-fuchsin or aldehyde-fuchsin staining, and are highly resistant to boiling water, in contrast with collagen fibres which are easily gelatinized in hot water.” (Ushiki, 2002)

“Electron microscopy has also revealed the ultrastructures of these fibrous components, namely that the collagen and reticular fibres are composed of fibrils with a unique banding pattern (ScHmirr et al., 1942), and elastic fibres comprise both fibrous and amorphous elements (GREENLEE et al., 1966). Advances in biochemistry and immunohistochemistry have also provided detailed information on the nature of these fibrous components, and a number of reviews are available, especially in consideration of the biochemical properties of the fibrous components (e.g., Ross, 1973; SANDBERG et al., 1981; KUHN, 1987; also see books edited by HAY, 1991; YURCHENCO et al., 1994)” (Ushiki, 2002)

>> Collagen

a. Collagen Fibres – Basic Structure

“Fresh collagen fibres are colourless strands 1 to 100 μm thick that usually follow a wavy course without branching in tissues. These fibres are stained pink with eosin and green with the Masson trichrome staining method (Fig. la).” (Ushiki, 2002)

“Electron microscopy shows collagen fibres to be a bundle of closely packed thin fibrils with periodical cross striations (SCHMITT et al., 1942) (Fig. lb, c); these unit fibrils are called “collagen fibrils.” ” (Ushiki, 2002)

“In specimens stained with a cationic dye such as Alcian blue and Cupromeronic blue, very thin filaments (less than 10 nm thick) are visible within the bundle of collagen fibrils (Fig. Id) (Scum’, 1980, 1988, 1995; SCOTT and ORFORD, 1981; RUGGERI and BENAZZO, 1984, RASPANTI et al., 2002). These filamentous structures have been considered proteoglycans, including large dermatan sulfate proteoglycans and such small molecules as decorin (FLEISCHMAJER et al., 1991). The proteoglycan filaments appear to connect neighbouring collagen fibrils by transversely and periodically attaching to a specific site of the fibrils.” (Ushiki, 2002)

“These findings indicate that proteoglycans play a role in synchronizing the position of bands in neighbouring fibrils and determine the distance of two neighbouring fibrils to fasten themselves into a bundle.” (Ushiki, 2002)

“Thus, the structure of collagen fibres in which parallel fibrils are bundled with flexible proteoglycans is in accordance with their mechanical properties, since collagen fibres are flexible but offer great resistance to a pulling force.” (Ushiki, 2002)

Fig. 1. Collagen fibres observed by light microscopy (a), TEM (b) and SEM (c, d). a. Collagen fibres in the dermis in the human skin. These fibres are stained pink with hematoxylin-eosin and run in various directions. x 200.
b. Longitudinal section of a collagen fibre in the dermis of the human skin. The light-microscopically determined collagen fibre is a bundle of collagen fibrils. Note single fibrils (arrowheads) running independently from the bundle. x 21,000. c. SEM image showing the three-dimensional structure of the collagen fibre in the mouse peritendineum (any of the fibrous sheaths surrounding the primary bundles of fibres in a tendon). The collagen fibre is observed as a bundle of closely packed collagen fibrils with characteristic transverse hands. x 62,000 (Bar=100 nm). d. Closer view of a collagen bundle in the rat aortic adventitia, which has been treated with a 2% glutaraldehyde solution containing 0.05% Aldan blue and 0.3 M MgCL (0.025 acetate buffer, pH, 5.8). Thin filamentous structures (arrowheads) appear to connect neighbouring collagen fibrils by attaching transversely and periodically to a specific site of collagen fibrils. x 155,000 (Bar =100 nm)

b. Collagen Fibres – Arrangement

“The size and shape of collagen fibres (i.e., bundles of collagen fibrils) vary depending on tissues and organs, even within the same species. They are usually of a cord- or tape-shape with a width of 1-20 μm, and take a wavy course (Fig. 2a, b), even if they form dense fibrous connective tissues such as the tendon (ROwE, 1985). The wavy arrangement of these fibres probably provides resilience to the fibres themselves, which also serves as a cushion against the direct tension to collagen fibres.” (Ushiki, 2002)

“In loose connective tissues, collagen bundles sometimes run parallel to each other to be twined into a larger bundle, while they come to split and join by changing the number of collagen fibrils, thus forming a three-dimensional meshwork throughout the tissues. Much thinner fibres also often participate in the collagen fibre network (ORBERG et al., 1982; USHIKI and IDE, 1990); these fibres are composed of single or several collagen fibrils, which are produced by leaving the thicker fibers to rejoin them in another portion. This fibrillar network is similar to the network formed by reticular fibres, but does not have argyrophilic  properties (i.e. do not readily stained black by silver salts).” (Ushiki, 2002)

This fibrillar network probably plays a role in maintaining a specific arrangement of collagen fibres in each tissue and organ.

Fig. 2. The shape and arrangements of collagen fibers observed by SEM. a. Cord-shaped collagen fibers entangled in the human subcutaneous tissue (Subcutaneous tissue is the deepest layer of your skin. It’s made up mostly of fat cells and connective tissue. The majority of your body fat is stored here). x 1,700 (Bar =5 μm). b. Tape-shaped collagen fibers in the rat aortic adventitia. Much thinner bundles or single collagen fibrils (arrowheads) leaving thick bundles form a loose net around collagen bundles. x 2,200

c. Collagen Fibres – Structure of the collagen fibrils

“As described above, collagen fibrils are unit fibrils which can be observed in individual collagen fibers by electron microscopy (Fig. 3a, b). These fibrils are cylindrical in shape with a diameter ranging from 10 to over 500 nm (mean diameter about 40-80 nm) in mammals (PARRY and CRAIG, 1984). They show periodical striations (which are alphabetically named the A-E bands) in positively stained sections (ScHmiTT and GROSS, 1948; BRUNS and GROSS, 1974), while the characteristic alternation of dark and light zones is found along the negatively stained fibrils by TEM (TROMANS et al., 1963, OLSEN, 1963). The periodicity of these structures is determined by the length of the two closest D-bands in positively stained fibrils and called D-periodicity. The surface morphology of the collagen fibrils has also been studied by TEM of shadowed materials (GROSS and SCHMITT, 1948) and freeze-fractured replica (MARCHINI and RUGGERI, 1984; RASPANTI et al., 1989), SEM (RASPANTI et al., 1996) and AFM (Fig. 3c, d) (BASELY et al., 1993; USHIKI et al., 1996; YAMAMOTO et al., 1997). These studies revealed the presence of periodical grooves and ridges on the surface of collagen fibrils, which correspond to dark and light zones of negatively stained fibrils, respectively.” (Ushiki, 2002)

Numbers of studies have been devoted to the arrangement of collagen molecules in each fibril (e.g., see review of CHAPMAN and HULMES, 1984). They established that the periodic structure in collagen fibrils arises because the molecules about 300 nm long are assembled in parallel array and are mutually staggered by integral multiples of a D-period. The D periodicity has been estimated by electron microscopy and low-angle X-ray diffraction methods. Low angle X-ray diffraction of collagen fibrils showed that D is close to 67 nm in wet samples, and around 64 nm in air-dried samples (BEAR, 1944; BRODSKY and EIKENBERRY, 1982). By electron microscopy, D varies from 64-70 nm in ultrathin sections, and the variability has been interpreted as the effect of various degrees of shrinkage caused by the dehydration and embedment of samples. In contrast, some authors claim that the D-periodicity differs among collagen fibrils in different organs; for example, the D-periodicity of bovine corneal collagen fibrils was reported by X-ray diffraction to be shorter than that of rat tail tendon collagen fibrils (MARcBINI, et al., 1986).” (Ushiki, 2002)

“On the other hand, the presence of subfibrils in collagen fibrils has been reported by previous investigators using TEM of such samples as glycerinated or denatured tissues (Fig. 4a) (e.g., BOUTEILLE and PEASE, 1971; RAYNS, 1974; LILLIE et al., 1977). These studies indicate that right-turning subfibrils are tightly packed in individual collagen fibrils. RUGGERI et al. (1979) also noticed that the subfibrils have a straight or helicoidal arrangement depending on the types of tissue located.  Ushiki (2002) investigated collagen fibrils of the cornea and sclera by AFM, and found a difference in D-periodicity between corneal and scleral fibrils in relation to the inclination angle of the subfibrils  (YAMAMOTO et al., 2000a). More precisely, the corneal collagen fibrils (with a D-periodicity of 63 nm) show a helicoidal arrangement of right-turning subfibrils with a 15° spiral angle, while subfibrils in the scleral collagen fibrils (with a periodicity of 67 nm) run almost longitudinally along the fibrillar axis. The relationship between these subfibrils and collagen molecules is still an open question (CHAPN4AN and HULMES, 1984), although several authors consider the subfibrils to be aggregations of small numbers of collagen molecules (VEis, et al., 1967; SMITH, 1968; BOUTEILLE and PEASE, 1971).” (Ushiki, 2002)

Fig. 3. Collagen fibrils observed by TEM (a, b) and AFM (c, d). a. Collagen fibril (in the mouse tail tendon) stained positively with uranyl acetate and lead citrate. The fibril shows periodical striations with an identity period of about 67 nm. Arrowheads indicate d-bands.  x 105,000. b. Collagen fibril (in the mouse tail tendon) stained negatively with phosphotungstic acid. The characteristic alternation of dark and light zones is found along the fibrils. x 105,000. c. AFM image of a bovine scleral collagen fibril. The fibril has periodical transvers grooves and ridges. Shallow longitudinal grooves are also found on the surface of collagen fibrils. d. The longitudinal section profile of the scleral collagen fibril between two asterisks in c. The height as well as the width of each portion can be measured from this profile. (Fig. 3a and b are from Mr. S. HAYASHI, Iwate Medical University. Fig. 3c and d are reproduced from YAMAMOTO et al., 2000a with permission).

“The diameter of collagen fibrils varies from 10-500 nm, depending on the locations of the tissues as well as the age and species of animal (PARRY and CRAIG, 1984). For example, the cornea has collagen fibrils with a regular diameter of about 30 nm, while the diameter of scleral collagen fibrils variously ranges from 25-230 nm (KomAi and USHIKI, 1991, YAMAMOTO et al.,1997). Collagen fibrils in tendons and ligaments show differing diameters with a peak one of 100-200 nm (PARRY et al., 1978). Another example is the diameter of collagen fibrils in the peripheral nerves (UsHIKI and IDE, 1990), where fibrils are thicker in the epineurium than in the endoneurium in various mammals (Fig. 4d). What determines the shape and size of collagen fibrils is an interesting question. Some investigators believe that the copolymeration of collagen molecules with other components of the extracellular matrix may influence the diameter of the fibrils formed (see review of CHAPMAN, 1989), while others have stated the importance of the copolymerization of different kinds of collagen molecules in one fibril (LAPIERE et al., 1977, FLEISCHMAJER et al., 1985, also see review of PROCKOP and HULNIES, 1994).” (Ushiki, 2002)

d. Collagen Fibres – Collagen molecule and its assembly

Fig. 4 a. SEM view of collagen fibrils (of the mouse tail tendon) treated with 8 M urea in a 0.2 M Tris-HCI buffer for 30 min. Longitudinal clefts are found in the individual fibrils, suggesting the dissociation of subfibrils. D-banding is still preserved in the denatured fibrils.  x 49,500 (Bar =100 nm). b. Collagen type I molecules observed by AFM. This molecule is observed as flexible thread 300 nm long. Globular bulges are present at both ends of the molecule. x 192,000 (Bar = 50 nm). c. Procollagen I molecules observed by AFM. Arrowhead indicates a globular C-terminal propeptide. (This sample was kindly provided by Dr. Fumio NAKAMURA, Hokkaido University) x 150,000 (Bar =50 nm). d. TEM view of a transverse section of connective tissue sheath in the rat sciatic nerve. This section comprises the whole thickness from the epineurium (Ep), through the perineurium (P) to the endoneurium (En). The diameter of the collagen fibrils is 30-100 nm in the epineurium, 30-60 nm in the perineurium and 40-45 nm in the endoneurium. x 16,500 (Bar= 1 gm)

“Chemical studies have revealed that the type I, II, and III collagen molecules self-assemble into banded fibrils. The shape of these collagen molecules has been studied previously by TEM using shadowing techniques (e.g., SILVER and BIRK, 1984; see also a book edited by MAYNE and BURGESON, 1987), and recently by AFM (SHATTUCK et al., 1994; LIN et al., 1999; YAMAMOTO et al., 2000b). As for the type I molecules, they are thin and flexible threads about 300 nm in length in contrast with type I procollagen molecules with a globular C-terminal propeptide and fuzzy N-terminal propeptide in either end (Fig. 4h, c). The individual collagen fibrils are generally considered to be formed from collagen molecules by their self-assembly process in the extracellular environment (BIRK et al., 1995; KADLER et al., 1996). Our SEM studies showed a process of collagen fibril assembly in cultures of human osteosarcoma cells (HASHIZUME et al., 1999); the findings clearly showed that short and thin collagen fibrils (about 1 μm long and 30 nm thick) with tapered ends fused with each other in a helical direction with their periodicity synchronized with each other, forming longer and thicker collagen fibrils. During this process, the banding pattern from end to end in the fibrils is unidirectional, indicating that  the  directions of the collagen molecules are uniform  throughout  the  length  of  the  individual fibrils.” (Ushiki, 2002)


“Basic structure of reticular fibers in relation to their staining properties. Reticular fibers are fine fibers forming an extensive network in certain organs. By light microscopy, these fibers are not visible in conventional stains such as hematoxylin and eosin, but are stained dark with a silver impregnation method (Fig. 5a) (MALLORY and PARKER, 1927; FOOT, 1928; NAGEOTTE and GUYON 1930). Thus, reticular fibers are also called argyrophilic fibers. The distribution of reticular fibers is rather restricted: they are usually found mainly in the basement of epithelial tissues, the surface of adipose cells, muscle cells and Schwann cells, outside the endothelium of the hepatic sinusoid, and the fibrous reticulum of lymphoid tissues. These fibers have a diameter of less than 2 μm. Although there are several modifications of BinscHowsKY’s impregnation method (MAREscH, 1905), a method reported by IsHII and ISHII (1965) yields specimens with suitable representation showing the fine structure of reticular fibers. In these specimens, reticular fibers are meshworks of very fine, dark fibrils, and are continuous with thin and reddish collagen fibers (Fig. 5a).” (Ushiki, 2002)

Fig. 5. Reticular fibers obserbed by light microscopy (a) and electron microscopy (b-e). a. Reticular fibers of the human lingual muscle stained by a modification of Bielschowsky’s impregnation method of Ism and Isliff (1965). Reticular fibers are observed as a meshwork of very fine, dark fibrils, which surrounds the muscle fiber as the endomysial sheath. Note reddish collagen fibers continuous with the dark reticular fibers of the endomysial sheath. x 1,500. b. Reticular fibers surrounding a rat lingual muscle fiber. Thin collagen fibrils and their small bundles are tightly attached to the basal lamina of the muscle fiber. x 8,500. c. TEM view of a silver impregnated section of the dog lingual muscle. The reticular fibers are composed of a bundle of argyrophilic fibrils attached to the basal lamina of skeletal muscle fiber. x 14,000. d. Backscattered electron (BSE) image of the reticular fibers of the human hepatic sinusoid by SEM. Because the BSE yield strongly depends on the average atomic number of structures (UsHixi and FUJITA, 1986), metal particles are clearly visualized as highlights in this micrograph. Thus, it is clear that the individual fibrils of the reticular fibers are densely coated with coarse metal particles. x 33,000. e. BSE image of a collagen fiber of the interlobular connective tissue in the human liver. Fine metal grains are sparsely deposited on the surface of the collagen fibrils. x 33,000 (Specimens of Fig. 3a, c-e were kindly provided by Prof. emer. T. ISHII, Tohoku University)

“Electron microscopy shows reticular fibers as individual collagen fibrils or a small bundle of collagen fibrils (Fig. 5h). These collagen fibrils have striations with a characteristic D-banding pattern similar to fibrils in collagen fibers, but their diameter is rather thin and uniform, ranging from 20-40 nm. Observations of silver-impregnated sections by TEM and SEMI (using backscattered imaging) show that individual collagen fibrils in reticular fibers are densely coated with coarse metal particles, while fine granular particles are sparsely found on fibrils in collagen fibres (Fig. 5c-e) (ScHwARTz, 1953; USHIKI, 1992b). This indicates that the size and density of metal precipitation particles determine the difference in tone between reticular fibers and collagen fibrils light-microscopically.” (Ushiki, 2002)

“Reticular fibers are also PAS-positive and have an affinity to cationic stains such as Ruthenium Red (IDE et al., 1989). These findings suggest that the surface of the individual fibrils in reticular fibers is embedded in an abundance of glycoproteins, which produce the stainability of fibers described above.” (Ushiki, 2002)

“Chemical and immunohistochemical studies, on the other hand, have revealed that reticular fibers, in contrast to collagen fibers composed of collagen type I, comprise mainly collagen type III (FLEISCHIVIAJER et al., 1980; MONTES et al., 1980) in association with other types of collagen (e.g., collagen type V), glycoproteins (STENNIAN and VAHERI, 1978), and proteoglycans/ glycosaminoglycans (MONTES et al., 1980; NISHIMURA et al., 1996). The difference in collagen type between collagen fibers and reticular fibers might be related to the diameter of the fibrils in the two fibers, although further studies will be needed in this point.” (Ushiki, 2002)

Fig. 6. SEM views of reticular fibres in specimens treated with an alkali-water maceration method by 011TANI (1987). In these specimens, cellular elements, elastic fibres and basal laminae are completely removed without any severe damage to the collagen fibrils of reticular fibres. a. Endomysial reticular fibres (R) of the dog lingual muscle. The space for accommodating the skeletal muscle fibre is demarcated by a cylindrical sheath of reticular fibres. Note the thicker collagen bundle (or collagen fibres, C) following a wavy course outside the endomysial sheath. x 1,200. b. Closer view of a part of Figure 6a. The sheath of reticular fibres consists of thin collagen fibrils, which are elaborately interwoven into delicate patterns of lacework. x 4,200. c. Reticular fibers in the deep cortex of the rat mesenteric lymph node. Because the cellular elements such as reticular cells and lymphocytes were removed by the maceration method, the three-dimensional network of reticular fibers can be directly observed by SEM. B the reticular sheath for blood vessels.  x 570, d. Closer view of the sheath of reticular fibers for blood vessels in the same specimen of Figure 6c. This sheath is observed as a lacework of thin collagen fibrils. Arrow indicates that portion where collagen fibrils in this sheath are continuous with thicker bundles of collagen fibrils as a reticular framework of the lymphoid tissue. x 1,400

a. Reticular Fibers – Arrangement

“The arrangement of reticular fibers is important for understanding the functional role of the fibers in tissues and organs, and was first studies mainly by light microscopy (PLENK, 1927; NAGEOTTE and GUYON, 1930). SEM further revealed the threedimensional architecture of reticular fibers in relation to the surrounding components (e. g., MOTTA, 1975; SAWADA 1981; USHIKI and IDE, 1986). The method introduced by OHTANI (1987) is also useful for visualizing the fibrillar arrangement more directly and precisely by SEM, since it successfully removes cellular elements, elastic fibers, and basal laminae without any severe damage to the collagen fibrils.” (Ushiki, 2002)

“These findings show that reticular fibers form a delicate network of fine fibrils which underlie the basal lamina of such cells as epithelial, muscle and Schwann cells (OHTANI, 198.8, OHTANI et al, 1988, 1991, USHIKI and IDE, 1990, MURAKUMO et al., 1993). The firm attachment of the individual fibrils with the basal lamina indicates that the collagen fibril meshwork and the basal lamina, as a whole, form a distinct structural unit for the demarcation and support of cellular components (USHIKI and IDE, 1986; USHIKI et al., 1990).” (Ushiki, 2002)

“The reticular arrangement of the fibrils is also suitable for providing a space for molecular movement in the extracellular fluid. Concerning lymphoid tissues, reticular fibers act as a skeletal framework and support vessels and lymphatic sinuses within the tissues (USHIKI et al., 1995).” (Ushiki, 2002)

“Reticular fibers thus differ in structure, arrangement,  and function from collagen fibrils, but are continuous with collagen fibers. In this sense, the two fibrous components are considered to form an extensive network of collagen fibrils as the collagen fibrillar system (USHIKI, 1992b).” (Ushiki, 2002)

>> Elastic Fibres

“Elastic tissues of the body owe their mechanical properties to the protein elastin. In complete contrast to the highly orientated, inextensible collagen fibre the elastin fibre occurs naturally in a contracted state and is capable of reversible extension to about double its length. Elastin is therefore generally found in the form of fibres. It is also found as membranes in the elastic ligaments, elastic blood vessels, and other compliant tissues such as lung and skin. The elastic arteries contain concentric layers of elastic fibres, and the ligaments have parallel fibres (Partridge, 1962).” (Bailey, 1878)

“Elastin was at first defined solely by its histological appearance. Largely through the work of Partridge and his colleagues, a precise chemical definition of elastin was reported in 1958. However, it was not until the cross-links were identified by this group in 1963 (Thomas et al., 1963) that the field opened up and a significant understanding of the relationship of structure to function began to emerge.” (Bailey, 1978)

“Like collagen, elastin is an extracellular insoluble polymeric protein; hence its intracellular biosynthesis as a soluble monomer, its extracellular aggregation and subsequent stabilisation by crosslinking considerably resemble the biosynthesis of collagen fibres.” (Bailey, 1978)

Fig. 7. Elastic fibers observed by light microscopy (a) and TEM (b, c). a. Elastic fibers in the stretch preparation of the rat subcutaneous tissues stained with aldehyde-fuchsin and light-green. Elastic fibers are stained violet with aldehyde-fuchsin, while collagen fibers are observed green by light-green staining. x 125. b. TEM view of elastic fibers in the section stained with uranyl acetate and lead citrate. The elastic fiber is composed of an amorphous substance (or elastin, E) and microfibrils (arrowheads). x 77,000. c. Transverse sectoin of an elastic fiber stained with tannic acid and lead citrate. Elastin of the elastic fibers is stained dark in this micrograph. Arrows indicate collagen fibrils. x 65,000

a. Elastic Fibres – Basic Structure

“Elastic fibers are generally twisted or straight strands stained by a resorcin-fuchsin or aldehyde-fuchsin method (Fig. 7a); these fibers are about 0.2 – 1.5 μm and sometimes branch to form a coarse network in loose connective tissues. In dense elastic tissues such as the aorta, elastic fibers fuse to form flattened sheets, or elastic laminae. Biochemically, elastic fibers are highly resistant to boiling water, in contrast with collagen fibrils which are easily gelatinized in hot water (RICHARDS and GIES, 1902).” (Ushiki, 2002)

“By TEM of ultrathin sections stained with uranyl acetate and lead citerate, elastic fibers are seen to consist of amorphous and fibrous components (Fig. 7b) (GREENLEE et al., 1966; Ross and BORNSTEIN, 1969). Amorphous components are densely stained with tannic acid treatment by TEM (Fig. 7c) (MIZUHIRA and FUTAESAKU, 1972) and are composed of substances which can be purified in boiling water and are recognized biochemically as the protein named elastin (e. g., see a review of Ross, 1973). Elastin endows elastic fibers with the characteristic property of elastic recoil. Fibrous components, on the other hand, correspond to the microfibrils which were recognized by TEM in various tissues and organs by Low (1962). Microfibrils are 10 nm in diameter and composed of various glycoproteins, including fibrillin (SAKAI, et al., 1986) and the amyloid P component (INouE and LEBLOND, 1986; INOUE et al., 1986).” (Ushiki, 2002)

“By conventional SEM, elastic fibers are observed as cobwebbed cords entangled with microfibrils (Figs. 8a, b, 11b) (USHIKI, 1992b).” (Ushiki, 2002)

Fig. 8. SEM images of elastic fibers (a, b) and elastin components (c, d). a. Elastic fibers (E) in the mouse aortic adventitia. Elastic fibers are observed as coiled or straight cords entangled in the net of microfibrils. C collagen fiber. x 9,100. b. Closer view of an elastic fiber (in the mouse subcutaneous tissue). The elastic fiber is covered densely with microfibrils which run in various directions.  x 55,000. c. Elastin components of the rat aortic adventitia treated with the formic acid-digestion mothod (UsHiiti, 1992a). This method removes cellular components, collagen components and microfibrils from tissues, while leaving elastin components unchanged at their original locations. Elastin fibers in this micrograph are observed as cords running in various directions. Note a connection between two crossed fibers (arrow). x 5,500. d. Internal elastic lamina of the rat aorta treated with the formic acid-digestion method. The lamina appears as a solid sheet with two large fenestrations. The surface of the lamina is somewhat fibrous. Fibrous structures are also found in the fenestrations where the fibrils extending the lamina to form a meshwork like a wire fence. x 3,000.

b. Elastin Fibres – Arrangement

“Since elastic fibres are intermingled with collagen fibrils and cellular elements in tissues, it is usually difficult to demonstrate their arrangement both extensively and three-dimensionally. For this reason, previous SEM investigators have attempted to extract elastic fibres by autoclaving tissues (GRu’r et al., 1977), or by utilizing treatments with chemical agents and enzymes: e.g., guanizinium chloride, collagenase, sodium hydroxide, and formic acid (KUHN, 1974; KEWLEY et al., 1977; WASANO and YAMAMOTO, 1983; SONG and ROACH, 1985; CRISSMAN, 1987). These methods selectively remove non-elastin components including microfibrils, collagen fibrils and cellular elements, and are effective for observing the architecture of elastin components in tissues by SEM (Figs. 8c, d, 9c, d). On the other hand, the treatment of tissues with a KOH method is effective for observing the special relationship between elastin components and cellular elements by SEM, since this method removes collagen fibrils and basal laminae while leaving cellular and elastin elements unchanged at their original shapes and locations (Fig. 9a, b) (USHIKI and MURAKUMO, 1991).” (Ushiki, 2002)

“Through these studies, several investigators have demonstrated that elastin components form a continuous network or sheet with a smooth surface (KuHN, 1974; WASANO and YAMAMOTO, 1983), while others have considered them as a fibrous network or sheet composed of fibrils about 0.1-0.2 μm (KEWLEY et al., 1977; HART et al., 1978). Our previous studies revealed that the surface structure and organization of elastin components are changeable depending on the procedures after extraction, and yielded evidence that the elastin component including aortic laminae are fibrous when extracted tissues are adequately treated (UsHIKI and MURAKUMO, 1991; USHIKI, 1992a).” (Ushiki, 2002)

“Elastin components show morphological features specific to individual tissues and organs (UsHIKI and MURAKUMO, 1991). A typical organization of elastin fibers in the loose connective tissue is a loose network of elastin fibers about 0.2-1.5 μm thick (Fig. 8c). An elastin sheet lining the serosal covering of the mesothelium consists of fine fibers ranging from 0.1- 1.0 μm thick, which run in various directions two-dimensionally and are elaborately interwoven, forming a delicate lacework-pattern (Fig. 9a, b). Elastic laminae in the aorta appear as a solid sheet about 2 μm thick with numerous oval fenestrations of varying diameters from 1-10 μm (Figs. 8d, 9d).  These laminae appear to be composed of fibrous structures about 0.1-0.2 μm thick. It is therefore evident that extracted elastin components are basically composed of thinner fibrils about 0.1-0.2 μm thick (Fig. 9h), even though some investigators further recognized very thin (3-4 nm thick) elastin filaments by TEM of negative-stained or freeze-etched specimens (GOTTE et al., 1974; FORNIERI et al., 1982). The elastin fibrils are present individually or in bundles, and so form elastin fibrils, fibers and/or laminae in individual tissues (Fig. 10) (UsHIKI and MURAKUMO, 1991).” (Ushiki, 2002)

“The organization of elastin fibers and laminae apparently influences the resilience of tissues suitable for their mechanical properties. Concentric elastic laminae with connecting interlaminar fibers are suitable for distributing blood pressure uniformly and effectively to the vascular wall. The elastic sheet lining the mesothelium is believed to give elasticity to the serous membrane and protect the mesothelium against any distention and contraction of such organs as the lung and urinary bladder.” (Ushiki, 2002)

Fig. 9. SEM images of elastin components after KOH (a, b) or formic acid (c, d) treatmemt. a. Elastin observed in the serosa of the mouse urinary bladder. The mesothelium (M) is removed in the lower right of the micrograph, where elastin forms a delicate pattern of lacework. x 1,300. b. Closer view of the elastin network in the serosa. The network is composed of fine elastin fibers and fibrils, which run in varoius directions and are elaborately interwoven. x 2,500. c. High magnification of an elastin fiber in the adventitia. The elastic fiber is seen as a bundle of fine fibrils about 0.1-0.2 μm. x 15,000. d. Part of transverse section of the rat aortic media. The medical elastic laminae and interlaminar elastin fibers are observed. x 1,500 (Fig. 9a is reproduced from USHIKI and MURAKUMO, 1991 with permission)

> Microfibril-elastin network system

“Microfibrils are usually present in and around elastin fibers, where they appear to be arranged in random directions to the elastin fibers (Fig. 8b) 1992b). In stretched fibers, the microfibrils change in their direction along the fibers, in response to stretching of the elastin fibers.  Microfibrils often leave elastin fibers to form a bundle or cobwebby meshwork in various tissues (Figs. 8a, 11b).” (Ushiki, 2002)

Fig. 10. Schematic drawing of elastin components. Elastin components are basically composed of unit fibrils about 0.1-0.2 μm thick. These elastin fibrils are present individually or in bundles to form elastin fibers, an elastin meshwork and/or elastin sheet in tissues.
Fig. 11 a. Light micrograph of the mouse subcutaneous tissue stained with aldehyde-fuchsin after oxidation with peracetic acid. Oxytalan fibers run in various direction like a cobweb throughout the tissue. Arrowheads indicate elastin fibers. x 50. b. SEM view of a part of the rat aortic adventitia. Microfibrils leave the elastic fiber (E) to form a bundle of microfibrils (0), which corresponds light-microscopically to the oxytallan fiber. C collagen fiber. x 11,000

“Light-microscopically, characterized fibrous structures are observed when sections are treated with peracetic acid before aldehyde-fuchsin staining (Fig. 11a) (FunmER and LILLIE, 1958). These fibrous structures are continuous with clastic fibres and are called oxytalan fibres. By TEM, the oxytalan fibres are observed as a bundle of microfibrils (Fig. 11b) (COTTA-PEREIRA et al., 1976). The oxytalan fibres can be also found in the zonule fibres of the eye and in the dermis where it connects the elastic fibres to the basal lamina. As far lymphatic vessels, oxytalan fibres act as anchoring fibres which connect the elastic fibres and lymphatic endothelium, thus preventing the collapse of initial lymphatics in tissues (Gum et al., 1990). In addition, so-called elaunin fibres (GAw-LIK, 1965) have intermediate characteristics between oxytalan fibres and elastic fibres by TEM (COTTA-PEREIRA et al., 1976). These findings indicate that microfibrils and  elastin  fibrils  produce  oxytalan fibres, elaunin fibres, and elastic fibres to form, as a whole, the microfibril-elastin fibre system which plays a role in maintaining the resilience adapted to local tissue requirements.” (Ushiki, 2002)

> Fibrillar System

What is the fibrilar system? Fibrils are structural biological materials found in nearly all living organisms. It differs from fibres which are longer than it is wide and filaments which are long-chain protein monomers as found in muscles and hair. Fibrils tend to have diameters ranging from 10-100 nanometers (whereas fibres are micro to milli-scale structures and filaments have diameters approximately 10-50 nanometers in size). Fibrils are not usually found alone but rather are parts of greater hierarchical structures commonly found in biological systems.

Wikipedia elaborates on the structure and mechanics of fibrils as follows. They “are composed of linear biopolymers and are characterized by rod-like structures with high length-to-diameter ratios.

Visualise length to diameter ratios. The bigger the number, the longer the strand. (Image from US Neodymium Magnets)

“They often spontaneously arrange into helical structures. In biomechanics problems, fibrils can be characterized as classical beams with a roughly circular cross-sectional area on the nanometer scale. As such, simple beam bending equations can be applied to calculate flexural strength of fibrils under ultra-low loading conditions. Like most biopolymers, stress-strain relationships of fibrils tend to show a characteristic toe-heel region before a linear, elastic region. Unlike biopolymers, fibrils do not behave like homogeneous materials, as yield strength has been shown to vary with volume, indicating structural dependencies. Hydration has been shown to produce a noticeable effect in the mechanical properties of fibrillar materials. The presence of water has been shown to decrease the stiffness of collagen fibrils, as well as increase their rate of stress relaxation and strength. From a biological standpoint, water content acts as a toughening mechanism for fibril structures, allowing for higher energy absorption and greater straining capabilities.

Fibrils mechanical strengthening properties originate at the molecular level. The forces distributed in the fiber are tensile load carried by the fibril and shear forces felt due to interaction with other fibril molecules. The fracture strength of individual collagen molecules is as a result controlled by covalent chemistry between molecules. The shear strength between two collagen molecules is controlled by weak dispersive and hydrogen bond interactions and by some molecular covalent crosslinks. Slip in the system occur when these intermolecular bonds face an applied stress greater than their interaction strength.”

“Intermolecular bonds breaking do not immediately lead to failure, in contrast they play an essential role in energy dissipation that lower the stress felt overall by the material and enable it to withstand fracture.  These bonds, often hydrogen bonding and dispersive Van der Waals interactions, act as “sacrificial” bonds, existing for the purpose of lowering stress in the network. Molecular covalent crosslinks also play a key role in the formation of fibril networks. While crosslinking molecules can lead to strong structures, too much crosslinking in biopolymer networks are more likely to fracture as the network is not able to dissipate the energy, leading to a material that is strong but not tough. This is observed in dehydrated or aged collagen, explaining why with age human tissues become more brittle.

> Fibrilogenesis

I quote two interesting comments from Gross (1958).

“Factors which may regulate the rate of fibril formation in systems in vitro are of interest from a physiological viewpoint for the clues they may give concerning mechanisms in viva, and from a physical chemical point of view for the light, they may shed on intermolecular reactions. Collagen soluble in cold neutral salt solutions has the interesting property of precipitating, on warming to body temperature,
as a rigid gel composed of fibrils with the characteristic axial periodicity of native collagen. It has been postulated that fibrils are formed under similar conditions in the extracellular tissues by spontaneous polymerization of collagen molecules secreted by the fibroblast into the ground substance.” (Gross, 1958)

In their paper Gross and Kirks (1958) describe some of the environmental factors which can influence the rate of fibril formation in neutral solutions of collagen. I made the paper available for download in the reference section below.

In their summary, they list the accelerators of fibril formation being SCN-, HCOB-, I-, Br-, F-, Cl-, in that order of effectiveness as measured by their relative ability to reverse the inhibitory effect of urea. Lysine
and Li+ were also strong accelerators of gelation.

Karl Kadler did a mini review of collagen fibrillogenesis in response to him receiving the Fell Muir Prize for 2016 by the British Societyof Matrix Biology. I have his article available for download in the referense section.

Fibrillogenesis “is the process by which triple helical collagen molecules assemble intocentimetre-long fibrils in the extracellular matrix of animals. The fibrils appeared abillion years ago at the dawn of multicellular animal life as the primary scaffold fortissue morphogenesis. The fibrils occur in exquisite three-dimensional architecturesthat match the physical demands of tissues, for example orthogonal lattices in cornea, basket weaves in skin and blood vessels, and parallel bundles in tendon, ligament and nerves.” (Kadler, 2016)

“Creating collagen vibrils in vitro is of the greatest interest for our study. Kadler refers to the work of Gross and mentions other researchers when he writes, “Gross (Gross & Kirk 1958), Wood & Keech (Wood & Keech 1960), Hodge & Petruska (Hodge 1989), Silver (Silver & Trelstad 1980) and Chapman (Bard & Chapman 1968), to name a few, showed that exposure of animal tissues (typically skin and tendon) to weak acidic solutions (typically acetic acid) or neutral salt buffers yielded a solution of collagen molecules that when neutralized and warmed to approximately 30°C, produced elongated fibrils that had the same alternating light and dark transmission electron microscope banding appearance as fibrils occurring in vivo (Holmes & Chapman 1979).” (Kadler, 2016)

“The characteristic banding pattern of the fibrils arises from D-stagger-ing of triple-helical collagen molecules that are 4.49Dinlength (where D is 67 nm, to a close approximation). The electron-dense stain used at neutral pH penetrates more readily into regions of least protein packing (the ‘gaps’) between the N- and C-termini of collagen molecules that are aligned head-to-tail along the long axis of the fibril. The fact that fibrils with D-periodic banding could be formed in vitro from purified collagen showed that all the information required to form a collagen fibril was contained within the amino acid sequence and triple helical structure of the collagen molecule (Hulmeset al.1973).” (Kadler, 2016)

> Elastogenesis

Fig. 12. SEM of a medial elastin laminae in the developing mouse aorta (at embryonic day 18.5) after KOH treatment. a. The elastic lamina is observed as a thin and fibrous sheet with numerous fenestrations. x 1,800. b. Closer view of the elastic lamina. The elastic lamina is composed of fine elastin fibrils, which run twodimensionally in various directions to form a thin fibrous sheet. x 11,000

“Previous TEM studies have demonstrated that bundles of microfibrils first appear during elastogenesis (ALBERT, 1972; SPICER et al., 1975). Elastin components are produced as the deposition of a small amount about 0.1 μm wide within the bundle. As the elastin components increase in number, they fuse together to become mature elastic fibers. According to our SEM studies on the extracted elastin components in the developing aorta, elastic laminae are first observed as a meshwork of fine elastin fibrils which increases in its density of elastin fibrils in the meshwork to become an elastic lamina with numerous fenestrations (Fig. 12a, b). These findings support the idea that microfibrils produce a fundamental framework of the microfibril-elastin system, which is added by the deposition of elastin fibrils about 0.1 μm thick, thus forming elastic fibers and laminae continuous with oxytalan fibers. Elaunin fibers are considered a transition form between oxytalan fibers and elastic fibers.” (Ushiki, 2002)

Conclusion by Ushiki (2002)

Fig. 13. Schematic representation of collagen fibrillar system and microfibril-clastin system. The collagen fibrillar system (green) composed of collagen fibrils which form thick bundles (i. e., collagen fibers, C) in the connective tissue and are arranged in a lace-like sheets or sheath (i. e., reticular fibers, R) attached to the basal laminae (yellow) of such cells as epithelial, endothelial or muscular ones. Thus, the collagen fibrillar system acts as a supporting framework of tissues and organs. The microfibril-elastin system is composed of microfibrils (fine solid lines) and elastin fibrils (violet), which usher in different proportions of the two components, to produce elastic (F), elaunin and oxytalan fibers (0). These three fibers of the microfibril-elastin system are continuous with one another, and form a three-dimensional network in tissues for maintaining the resilience adapted to local tissue requirements. Ep epithelium, V blood capillary, L initial lymphatic, F fibroblast.

“The present review describes the features of three major fibrous components: collagen, reticular and elastic fibers. For a comprehensive understanding of the fibrous components in connective tissues, we propose categorizing them into two systems (Fig. 13): the collagen fibrillar system and microfibril-elastin system. The collagen fibrillar system acts as a supporting framework of tissues and cells, where reticular fibers connect collagen fibers with the basal laminae of such cells as epithelial, muscle, adipose and Schwann cells. The microfibril-elastin system is composed of microfibrils and elastin fibrils, which use different proportions of the two components to produce elastic fibers, elastin fibers and oxytalan fibers. The microfibril-elastin system thus plays a role in distributing stress forces uniformly in tissues.” (Ushiki, 2002)

Eben’s Conclusion

The above discussion has several applications in the sausage-making industry. When one has raw material available such as hides/ skin, one must consider the options what the material can be used for:

  1. Skin or tendon emulsion can be made where the object is water binding;
  2. Collagen or skin chunks can be made, not to retain water but to provide firmness to the sausage matrix. In this instance it will be advisable not to hydrate the collagen or skins.
  3. If a fine emulsion is made with no show pieces, one can pre-prepare the fine skins/ tendons in the bowl chopper or micro-cutter seperately before the susage blend is made. Add the dry skin/ tendons towards the end of the blending process after all the water has been added.
  4. One must cook/ smoke with optimal crosslinking in mind.
  5. If unhydrated skin/ tendons are used, it should be possible to use a higher inclusion ratio than if its used in hydrated form.
  6. Hydration has an impact on the “solidness” of the sausage and its pastiness (resistance to bite). Amount used and hydrated or unhydrated are two of the most basic parameters which must be tested for when formulating a sausage with a high percentage of skin/ hide/ tendons included.
  7. I will incorporate the ingreadients tested by Gross (1958) and dealt with under Fibrilogenesis above, in my trails.
  8. Where resistance to boiling water is required (no gelatinization), I will be interested in, for example, the aorta which is rich in elastin fibers.

B. How are Collagen Casings made?

In this last section, I want to expose myself to more techniques used in the industry to manipulate skin or tendons. How do they do it? I first quote a traditional meat-man, explaining the basic process of producing collagen casings from beef hides.

Two Process overviews

The corium layer (splits) of USDA Approved cattle hides is extruded from between the grain (hair) layer and the fat and muscle layer. The hide consists essentially of collagen.  Protein and water are chopped and mixed with lactic acid and cellulose fibers causing them to swell and form a slurry.

The acid-swollen slurry is de-aerated under vacuum and is then homogenized and filtered to tease the collagen fibers apart.

The resultant slurry is again de-aerated and stored in chilled tanks.

It is then extruded through a die with counter-rotating sleeves, which “weave” the collagen fibers together as they pass through the die. The slurry, which is now in the form of a casing, passes directly into a concentrated coagulating solution of an inorganic salt.

The casing is then dried, partially re-humidified and wound on reels. The reels are taken to the shirring area where the collagen casing is shirred on machines similar to the type commonly used in the shirring of regenerated cellulose casings. (askthemeatman)

One of the many reasons why I think it’s counterproductive to take out a patent on certain inventions, especially chemical in nature, is because of what I am just about to do now. I refer you to US3413129A for Johnson and Johnson, invented by Emanuel R Lieberman. It is an invention of an alternative way to produce edible collagen casings. The invention was done in 1968 which makes this one of the first of its kind patents. I give the description next.


A collagen casing for sausages of the weiner or frankfurter type is manufactured by extruding a mass of acid-swollen collagen fibrils obtained from animal hide and cellulose fibers into an ammonium sulfate coagulating bath, hardening the extruded casing in an aqueous solution containing from about 0.15 percent to 10 percent by weight of ammonium hydroxide and a non-toxic ammonium salt, plasticizing the hardened casing, drying the casing. While inflated, heating the dried casing from C. to C. over a period of 8 to 12 hours, and then heating said casing for an additional 12 to 24 hours at about 80 C. This invention relates to an improved collagen casing and more particularly to extruded collagen casings that have been treated with an aqueous solution of ammonium hydroxide. While not limited thereto, the present invention is adapted to being utilized as a casing for sausages of the weiner or frankfurter type. Prior to the present invention, this type of sausage was either prepared by using expensive natural casings or inedible cellulose casing to contain the meat emulsion during the smoking and cooking process. The inedible cellulose casing must be removed by the manufacturer before the wieners are packaged for sale. The resulting product is known in the meat industry as a skinless Wiener.

There has long been a need for an extruded collagen casing that would be edible, non-toxic and sufficiently strong to stand up under stuffing, linking, smoking, washing and cooking. It is now known that edible casings for pork sausage may be prepared by extruding a tubular body from a fluid mass of swollen collagen fibrils, hardening this tubular body in the wet state and drying the collagen casing so produced. A method of producing such collagen casings is described in US. Patent No. 3,123,482.

Extruded collagen casings that are suitable for the manufacture of fresh pork sausages may not be entirely satisfactory for the production of sausages of the Wiener or frankfurter type. This is due to the differences in processing pork sausages and wieners. Thus, a meat emulsion of the pork sausage type may be stuffed, linked by twisting on a Famco linking machine, and packaged for sale without cooking. Sausages of the Wiener or frankfurter type, however, are linked on a Ty-linker, racked on a stick, smoked at temperatures from about F. to about F. or F. for several hours, rinsed with hot water at about 180 F. to F. for several minutes, and then rinsed with cold water for several minutes. The consumer may cook this product by deep fat frying, i.e., the frankfurter is plunged into a cooking oil that has been heated to 350 F. Sometimes such frankfurters have been chilled or even frozen prior to such cooking, so that the casings are subjected to great thermal stresses and pressures from steam or vapor generation. It will be appreciated, therefore, that a collagen casing used in the production of frankfurters must of necessity have a high wet strength to survive the more vigorous treatment in the linker.

An additional requirement for the frankfurter casing is that the casing should not become wrinkled and lose “ice bonding to the meat during smoking or the hot and cold rinses that follow smoking. In other words, the casing must be sufficiently elastic (not permanently deformed) so that the stress does not relax during the smoking rising cycle. On chilling after smoking, the meat contracts slightly (becomes more dense) and the casing must also shrink or the finished product will have a poor appearance.It is an object of the present invention, therefore, to produce a new and improved extruded collagen casing adapted to be utilized as a casing for sausages of the weiner or frankfurter type.

It is another object of the present invention to produce an edible casing that is exceptionally tender when eaten, yet sufficiently strong to survive linking in the Ty linker.

It is a further object of this invention to produce an edible collagen casing that will retain a smooth symmetrical appearance after smoking.

Still another object of this invention is to provide an edible collagen casing suitable for use with pork sausages or frankfurters that will not burst or peel off during cooking.

In accordance with the present invention, it has been discovered that a much improved Wiener casing may be produced by the procedure described in US. Patent No. 3,123,482 if a dilute solution of ammonia is substituted for the alum hardening agent. The use of ammonia in place of alum produces a casing that is more fragile and difficult to process during the manufacturing process. Yet the difficulty in processing is more than compensated for by the improvement in appearance and in-use performance of the finished casing.

Numerous laboratory and field tests have demonstrated that when an ammonia solution is substituted for the alum hardening solution in the process identified above, the product obtained more closely resembles natural casing. This difference is particularly apparent after stuffing, linking, smoking and cooking.

The fluid mass of swollen collagen that is extruded to form the casings of the present invention may contain from about 3.2 percent to about 4 percent by weight of collagen (calculated on the basis of dry collagen Weight) a non-collagenous filler such as cellulose or starch. If a fibrous filler such as cellulose is employed the amount may vary from about 5% to about 42% of the total solids present in the extrusion mixture. Smaller amounts of starch may be substituted for a part of or all of the cellulose.

The ammonia hardening bath may contain from about 0.15% to 10% ammonium hydroxide and from about 1% to 10% of a salt such as ammonium sulfate or ammonium lactate. To improve the wet tensile strength and elasticity of the ammonia hardened casing it is desirable to add a small amount of reducing sugar to the casing as described in US. Patent No. 3,151,990. The amount of reducing sugar employed, however, is only about one tenth of the amount required to treat an alum hardened casing. Indeed, the sugar treatment may be eliminated entirely if the ammonia hardened casing is heat-cured for a prolonged period of time, i.e., about 24 hours at 80 F.

Suitable sugars for the treatment of ammonia hardened collagen casings are reducing sugars which have a free aldehyde or keto group that is not in glucoside combination with other molecules. Examples of such reducing sugars are erythrose, threose, arabinose, ribose, xylose, cyclose, fucose, mannose, glucose (dextrose), galactose, fructose (levulose), etc. These sugars may be most conveniently applied to the collagen casing in the form of dilute solutions. The amount of sugar present in solution is related to the dwell time of the casing in the solution and the reactivity of the sugar used, and may vary from about 0.005 percent to about 0.08%. It is preferred to add the reducing sugar to the plasticizing bath, which bath follows the washing step and is the last bath contacted before the casing is dried.

Alternatively, a smoke solution derived from wood smoke vapor may replace the reducing sugar in the plasticizing bath. Smoke flavoring solutions contain a large number of acetic, phenolic and carbonyl (aldehyde) compounds that will react with collagen and improve the physical properties of the ultimate casing. The chemical constituents of smoke flavoring are discussed in’an article by Hollenbeck and Marinelli, Proceedings of the Fifteenth Research Conference, sponsored by the Research Council of the American Meat Institute Foundation of the University of Chicago, page 67 (1936). The smoke products identified in that article have been found useful in processing the ammonia hardened casings of the present invention.

The casing after it leaves the plasticizing bath is inflated and dried in a rapid stream of air and then heat cured in a forced draft oven, raising the temperature slowly from 40 C. to 80 C. during an 8 to 12 hour period. The heat treatment at 80 C. is continued for an additional 12 to 16 hours.

It will be understood that the foregoing general description and the following detailed description, as well, are exemplary and explanatory but do not restrict the invention.

The process for the manufacture of ammonia-cured collagen casings of the present invention may be more fully understood from the following detailed description and examples taken in connection with the accompanying drawings, wherein:

I include the full patent below for download.

Conclusion to Collagen Casings

The two processing overviews is enough to arm the NPD specialist with an ample starting point for investigating the production of skins/ hides and tendons to fulfil various function in fine emulsions. I refer you to the basic understanding of these emulsion type sausages in Review of comminuted and cooked meat product properties from a sol, gel and polymer viewpoint

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Ask the Meat Man

Bailey, A. J. (1978) Collagen and elastin fibres. J. clin. Path., 31, Suppl. (Roy. Coll. Path.), 12, 49-58

Gross, J., Kirks, D. (1958) The Heat Precipitation of Collagen from Neutral Salt Solutions:
Some Rate-Regulating Factors”

Kadler, K. E. (2017) Fell Muir Lecture: Collagen fibril formation in vitro and in vivo.

Jennifer Thomson, Mukti Singh, Alexander Eckersley, Stuart A. Cain, Michael J. Sherratt, Clair Baldock,
Fibrillin microfibrils and elastic fibre proteins: Functional interactions and extracellular regulation of growth factors, Seminars in Cell & Developmental Biology, Volume 89, 2019, Pages 109-117, ISSN 1084-9521, (

Ushiki, T.. (2002) Collagen Fibers, Reticular Fibers and Elastic Fibers. A Comprehensive Understanding from a Morphological Viewpoint. Division of Microscopic Anatomy and Bio-imaging, Department of Cellular Function, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan

Endless Possibilities: Re-thinking the 5th Quarter


I have been working on processing the 5th quarter with a range of new and traditional technology. Here I feature our newest developments. This page is put together for the NPD specialist to feature end products and raw materials resulting from the process.

I consider two distinct product classes namely products for the end-user and for the food processors to be used as ingredients in the production of other products.

For more information on DCD Technology, visit: The End of the Rendering Plant

A. Consumer products


I combined 40% beef body fat and 60% beef tendons (which by itself contains 20% fat) into a fat replacer. Here is a video I did when I evaluated the product.

In evaluating the fat replacer that Tristan and I made, and realised the taste was exquisite!

I posted it on my Facebook page. Someone remarked that it does not look appetising. The purpose was to create something that IS delicious which we achieved. The next step is to make it also look delectable. We achieve this with combinations. There are endless possibilities for collagen combination products. I list a few.

1. Maple Pumpkin Collagen Shake

This delicious shake is made with antioxidant-rich pumpkin puree and collagen, containing 20% fat

2. Sweet Potato Kwass & Collagen Shake, or Sweet Potato Puree & Collagen Shake.

Sweet potatoes are naturally sweet (hence the name), and even though it’s not a common flavour for a soda, it actually works really well. Sweet potatoes ferment very easily, and I had a super bubbly probiotic soda in no time with this sweet potato kvass recipe! (

We will re-work this recipe with DCD Technology.

3. Banting Beef Bone Broth, Collagen & Fat Mix

Mix dry bone broth into our collagen mix which contains 20% fat for a high protein, high-fat protein shake or to be sold in tubs as a stock replacer.

4. Vegetable Puree infused with Collagen

All dressings should contain a scoop of our collagen. It is great for use with vegetables!Vegetable puree has been shown to be a brilliant application of DCD Technology since it requires no e-numbers.

B. Industrial Product for Food Ingredients

1. Protein and Fat Enriched Collagen

Enrich the Collagen with pork stomach. Pork stomach on a dry basis contains 11% fat and 21% protein. The stomach proteins “coagulate” well which means that they are suited for inclusion in fine emulsion sausages. In combination with beef tendons, it blends into a beautiful fat replacer which is ideal for inclusion in canned products, bangers and other course sausages. The product settles into a firm solid homogenous mass after it has been reated. The new product has an added benefit for the formulation specialist in that it is packed with meat proteins and will contribute not just to the fat, but also collagen and meat protein requirements.

2. Beef Tendons with Beef Body Fat

The beef tendons contain about 20% fat along with collagen proteins. Infusing this with either pork lard or beef body fat change the properties of the fat in that it “contains” it during heating and it alters that mouthfeel considerably giving it a smooth, pleasant taste and mouthfeel.


The 5th quarter is one of the biggest opportunities for world-class new product developments. On this page, I share the various combinations we are working on. I will continue to feature end products and raw materials for further processing and will re-post this page from time to time.

Please mail me if you would want to be added to our mailing list of people we notify every month of our latest developments. Alternatively, sign up to our Facebook page where all updated pages will be posted or friend me on Linkedin where regular updates will appear.

Further Reading:

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Chapter 13.01.1: The Castlemaine Bacon Company

Introduction to Bacon & the Art of Living

The story of bacon is set in the late 1800s and early 1900s when most of the important developments in bacon took place. The plotline takes place in the 2000s with each character referring to a real person and actual events. The theme is a kind of “steampunk” where modern mannerisms, speech, clothes and practices are superimposed on a historical setting.  Modern people interact with old historical figures with all the historical and cultural bias that goes with this.

The Castlemaine Bacon Company

October 1960

Over the years I wrote letters to my kids telling them what I learn. It was also a handy way to chronicle my experiences. Through these, they followed my quest to produce the best bacon and how the universe thought me about life through the discipline and science of bacon. The last time they visited they had a surprise for me. They compiled all my letters into a book and asked me to write an introduction to every section. They also asked me to complete the work which I left in limbo when I returned as the pressure of setting up a bacon factory took precedence. They even contacted Dawie and Oscar, who both sent them my letters. The letters I write from Cape Town under the section, the Union Letters and the Best Bacon on Earth is the product of their request.

What follows is the account of companies who achieved perfection in the large-scale production of bacon. I also hone in on the “art of living” by introducing you further to Jan Kok and his remarkable family and I use the Anglo Boer War as a backdrop to paint the final picture of what bacon taught me about how to live life skillfully. Finally, I pay a photo album homage to Woodys and those who joined me on this remarkable journey and my children and Minette who remain my partner in life. To this group, I must add Julie and Johann. Julie and I remained friends.

I give three good examples of companies who achieved what I sought namely to produce the best bacon on earth! I think that for a time at Woody’s we produced exceptional bacon and when Duncan and Koos took over, things took a dip, but they are recovering beautifully. They found their own rhythm. The spirit of Woodys created by Oscar, the rest of the management team of Will and James and I will live on forever.

What makes the first such company to profile an exciting story is that the main character who created the Castlemaine Bacon Company fought in the Second Anglo-Boer War on the side of Britain. My great grandfather, his brother and his dad fought in the same war, but for the Boers. It was a fascinating project for me to compare diaries and see what our, now two, main characters did at certain times. The two men are Wright Harris and my great-grandfather is JW Kok and I refer to him simply as Jan Kok.

Their stories begin much in the same way. Their faith played an equally important role in surviving the war and it established a legacy where hard work, faith, and opportunity, determining the actions of their children and grandchildren and great-grandchildren. Both stories end with the creation of a bacon curing company!

The Anglo-Boer War

The exact cause why the war between England and the two Boer republics of the Orange Free State and Transvaal took place is not easy to answer. There is no one single reason. The easy itches that had to be scratched are obvious to see. The independent-minded, stanch, hard-line Calvinist Boers were looking for a fight with the most powerful empire on earth. They did not like the incessant mingling in their affairs. If they wanted to have black slaves and treat all non-white races as inferior, this was, according to them, their own business. On the other hand, individuals of the English nation had imperialistic aspirations for Africa and saw the Boers as inconveniently in control of the vast resources of the goldfields in Johannesburg and standing in their way to establishing English rule from the Cape to Cairo.

So it happened that a short but extremely costly and intense war was fought from 11 October 1899 to 31 May 1902. Some refer to this as the Boer War or the AngloBoer War, or the South African War. This was the first war of that scale which was fought, as it were, in front of the cameras lens. I dedicate an entire chapter to photos from the war in Chapter 19: The Boers (Our Lives and Wars) where not just the war but the Boer nation is featured beautifully. It is the backdrop of this work.

War is a dreadful phenomenon as it often sets in opposition, people who have a lot in common and who have respect for each other. Lord Lansdowne from Wiltshire, for example, a man whom I came to respect and admire on many levels became Secretary of State for War at the outbreak of hostilities. Faultlines in our human culture are accentuated during the time of war. Looking back at my own nation at war helped me to investigate our mental world and our reality as living life in our own mental worlds in a new light. The fact that I foresaw this war and the conflicts to come was the impetus for setting up Woody’s bacon which ultimately led me to a more complete appraisal of reality.

The inclusion of accounts from this war and the questions arising from it in a work on bacon appears counterintuitive, but it is exactly the hard look at ourselves and our people brought about by the heightened experience of the ether of life during the war, that took me back to the simple pursuit of bacon curing which the universe used to school me in the art of living.

Getting back to the subject at hand, for the life of me, I can’t remember who said this, but a bacon production manager in the UK quoted an English author who described the Boers as “stinking smelly bastards but they can shoot straight!” Such is the Boer soldier! England approached its other colonies to recruit soldiers to fight in South Africa. They recruited hardened and skilful men who could also ride and shoot straight, like the Boers. In this way, the South African War acted as a sieve. It highlighted good men on all sides. One such man, from Australia, was Wright Harris.

Wright Harris


Wright Harris before departure for the Boer War, 1900

The story of Wright Harris, the Australian protagonist, begins in England where his parents were married in January 1864 and migrated to Victoria, Australia. Wright was the 7th of 11 children. His father was a farm labourer and woodcutter. Wright remarked in later life that he left school at age 12 when hard work was the lot of most boys and added that “it didn’t hurt us.” Wright was a devout Christian. This heritage he got from his mother. By 1900 he was a regular lay preacher at many churches in the area. In this respect, he reminds me of our second main character, Jan Kok.

Jan Kok


Jan Kok at the house on Kranskop where he was born.

Jan Kok was born in the Winburg district in the independent Boer republic of the Orange Free State on 4 April 1880 to Johannes Willem Kok and Jacoba Elizabeth Theron. He was named after his dad. Altogether he had 10 siblings. The Orange Free State got its independence from Britain on 23 February 1854. Winburg itself was a self-proclaimed independent Boer territory since 1837 and was incorporated into the Free State in 1854. His grandfather, Johan Hendrik Christoffel Kock moved his family from Robertson in the Cape Colony to the Free State where he farmed on Besterschrik, 5km north of Korannaberg. Jan was christened on Windburg on 02 May 1880 and grew up right in the heart of Boer-self determination. His dad was himself a remarkable man. A veteran of the Basotho wars, he was commandant of one of the Windburg commandos. As a born leader, he had an indelible impact on the life of his son.

The Second Anglo-Boer War

War broke out in October 1899. The night after war was declared was ominous. A newspaper article in the 1900s described the scene that played itself out across the land. “All night the beacon fires had been burning on the higher kops. All night native runners had been scouring the country with messages from the commandants to the burgers. All night in many farmhouses the woman had been at work preparing the rations of biltong, and cleaning the arms of the patriots. All night throughout the length and breadth of the land prayers had gone up and the veld had echoed deep-voiced songs of David.” (The Philadelphia Inquirer, 1900) The aggression of the Boers who invaded Natal took the British by surprise and this gave them initially the upper hand. The British government responded by massing its forces from across the empire which included soldiers from Australia. Wright enlisted in February 1900 in the Victorian Bushmen Contingent.

Jack Harris in the Otto Würth smokehouse, 1993

P. L. Murray writes about the Third Bushmen Contingent in his work, Official Records of the Australian military contingents to the war in South Africa, “This corps was largely subscribed for by the public. It was resolved that, in lieu of drawing the men exclusively from the local forces, a class of Australian yeomen and bushmen should be obtained; hardy riders straight shots, accustomed to find their way about in difficult country, and likely to make an expert figure in the vicissitudes of such a campaign as was being conducted.”

An enormous number of candidates volunteered for enlistment. The men selected were largely untrained in military matters; 230 were farmers or with some connection to farming. The selection criteria were based on their ability to ride and shoot. The men were allowed to bring their own horses. Many brought two.

Wright Harris’s Victorian Bushmen Contingent, also known as the third Contingent Parades in Readiness to leave Cheltenham.

They left Melbourne for South Africa on 10 March 1900 aboard the Euryalis and arrived in Cape Town on 3 April 1900. Wright suffered from severe seasickness on the voyage to South Africa and wrote only two words in his diary, “sea sick.” Of the 261 men and NCO’s with 15 officers, 17 would lose their lives in the South African campaign.

Loading the horses on Euryalus for their journey to South Africa. Amongst the soldiers on board was Wright Harris.

Jan and his dad were involved in the bun fight right from the start. Jan’s dad makes no mention of being involved in the siege of Ladysmith in his war diary, but an obituary that appeared in a local newspaper after his passing claims that he was involved in the Natal campaign. Jan definitely was part of this campaign. He writes from Ceylon as a POW in his diary, on 16 December 1900, “Today it is 62 years after the victory over Dingaan. A year ago Reverant Kestel from Harrismith held a service for us in Natal under a thorn tree. Today I am a POW in Ceylon.”

Jan was on leave at home when his dad was fighting with Genl. Cronje in the efforts to prevent the British to capture Bloemfontein, the capital of the Free State. On 27 February Jan and his compatriots were forced to surrender. He vividly describes the scenes leading up to the surrender in his war diary. He writes, “The biggest battle at Paardenberg took place on Sunday. Something was set on fire in a large part of the camp. While the enemy continually tried to surround us they repeatedly used this tactic. The cannons fired without ceasing on us. The camp was almost completely destroyed when on the evening of 26 February we decided to surrender the morning of 29 February 1899.”

 He adds that “before I depart from the subject of this war, I want to address those who did not see this fiasco. No pen can describe the sadness that we endured and our eyes beheld. Almost all our horses were killed and were strewn throughout the camp. Our wounded lay in ditches under bucksails without a doctor to treat them. Yes, this I witnessed with my own eyes and I gave some water to quench their thirst. I got to someone whose leg was shot off. I asked him “How are you?” He answered me, “My Uncle, very badly!” I encouraged him. He politely asked me to come in and do a prayer for him. I complied with his request and then departed from him.”

“I could write more about this fiasco at Paardenberg but my pen refuses to write more about this suffering, or rather, it is I who don’t want to write about it any further. This is enough for successive generations to have an idea of what we went through.” (Johannes Willem Kok War Diary)

On 5 May 1900, the English invaded Windburg, Jan’s home town. His dad as a POW at this point gets the news on 8 May 1900 and writes in his diary, “We received word today that the English are in Windburg. It is not good news for us.” Jan himself makes the first entry in his war diary on 5 May and writes, “On 5 May the English occupied Windburg. On our farm, it was very busy on this day on account of the many commandos that passed through.” In the midst of these events, thirty-seven days earlier, Wright Harris and his comrades landed in Cape Town.

For Jan there was no time to lose and on the same day as Windburg fell on an autumn evening, the 20-year-old Jan Kok greeted his mum, took his rifle and mounted his horse. At 20:00 he rode off on commando (1) from their farm Kransdrif.

Departure of the Euryalus from Melbourne

As these scenes played themselves out, not only on Kranskop but on farms across the two Boer Republics, time and time again, from across the Empire, Britain was massing its forces and vessels sailed for South Africa and the men who came with the Euryalus were already on their way to the front.

From Kransdrift Jan and his compatriots rode to the farm of A. Nel, Kafferskop. In all, there were 11 people riding together; 6 from Winburg, 1 from Kroonstad, 2 from Thabanchu and two black people. They travel to Ficksburg, where they join the Kommando, and on 18 May they set off from Ficksburg to join larger Boer forces.

The Euryalus arrives in Cape Town.

From Jan’s diary, there was considerable disagreement about where they should go and which Boer forces they should join. The Australians, on the other hand, had none of the indecisiveness associated with a more informal military organisation of the Boers. As soon as they landed at Cape Town, they travelled to Beira and to Marondera (known as Marandellas until 1982), a town in Mashonaland East, Zimbabwe, located about 72 km east of Harare. Here, all the colonial Bushmen were formed into regiments known as the Rhodesian Field Force; “the Victorians and West Australians forming the 3rd, under Major Vialls. They marched in squadrons across Rhodesia (Zimbabwe) to Bulawayo. From there to Mafikeng where they were again mobilised and equipped and took part in one of the major battles of the war, the siege of Mafikeng.

Boer war 1

Photo supplied by Dirk Marais. Australian soldiers in the Anglo-Boer war, c. 1901

Wright noted the following entries in his journal at Mafikeng. 23 July, Monday. “Left Bulawayo for Mafikeng at 3 o’clock. Twenty-five in a truck, packed in like pigs.

24 July, Tuesday. “Ostrich running alongside the train. A halt for two hours at Palepwe to feed and water horses.” (I am not sure where Palepwe is. The name is probably misspelt)

25 July, Wednesday: “Met by an armoured train. Reached Mafikeng at about 6 o’clock, and slept out in the rain.”

Officers of the Third Victorian Contingent: Lieut W Strong, Lieut G Moore, Mr Cameron, Lieut H Trew, Lieut J Holdsworth, Lieut W McCulloch, Vet-Lieut Stanley Fletcher,
Lieut R Gartside, Captain D Ham, Colonel A Otter, Captain W Dobbin, Captain J Griffiths.

26 July, Thursday. “A look around the trenches and around Mafikeng. Saw the Boer prisoners, two sentenced to death.”

27 July, Friday. “Got our saddles. The ponies captured from the Boers allotted to us. Saw the guns that saved Mafikeng.”

28 July, Saturday. “Sent out to hold the river against the enemy with four guns. Got orders to go away and take three months provisions. Order countermanded (rescinded/cancelled).”

29 July, Sunday. “Church parade. Went to the Wesleyan church in town, had a grand service. Text Timoty 21 and 22. (This must be a mistake because there is no such reference. My guess is that it is 2 Tim 2: 21 and 22 which reads: “If a man, therefore, purges himself from these, he shall be a vessel unto honour, sanctified, and meet for the master’s use, and prepared unto every good work. Flee also youthful lusts: but follow righteousness, faith, charity, peace, with them that call on the Lord out of a pure heart.” On picket, got a piece of shell that had come through the roof.

British army (Western Front) under Field-Marshall Roberts marching on Brandfort in the Orange Free State, 1900 (Photo by Underwood & Underwood/Archive Photos/Getty Images). Foto by Leo Taylor

While Wright Harris was fighting at Mafikeng, Jan Kok found himself as part of a heavily demoralized Boer force in the Branwater basin. The capital of the Free State, Bloemfontein fell to the British. The Boer force where Jan was a part of included the Free State government and it was commanded by Gen Christiaan de Wet himself, the supreme commander of the Boer forces in the Free State. All in all the Boer force consisted of around 4000 men.

The situation for the Boers was dire. The British were at the point of annihilating all resistance in the Free State and dearly wanted to capture the entire Free State government. Gen De Wet made his escape plans and on 15t July he set out through Slabbertsnek with the Government and a contingent of Boer fighters. As the first phase of a carefully calculated plan was unfolding, the unthinkable occurred. A combination of quick and decisive moves from the English, poor leadership from the Boers in the face of enemy operations and the fact that the remaining Boer forces held a snap election when De Wet left and replaced Gen Roux, a DRC Minister and the man De Wet left in charge with Marthinus Prinsloo, a man, known to desire not to continue fighting and a huge morale loss amongst the Boer fighters all culminated in the Boer forces surrendering to Gen Hunter.

The events leading up to Prinsloo’s surrender is beautifully described by Jan who was an eyewitness of this monumental event. With compatriots, Jan hastens himself to Fouriesburg which temporarily served as the capital of the Freestate. He is assigned to guard General Prinsloo. He writes, “The night was bitterly cold. We slept in small groups behind the houses. Our group slept behind the house where Gen. Prinsloo stayed with his family.

The General must have received word of a night offensive by the Engish to capture Fouriesburg and he immediately moved out. Jan writes “We boiled out kettle in the house and at 2:00 the general woke us and we saddled our horses and we departed to a hill situated in the direction of the sunrise. We dismounted at the mill of Le Harp. We gave our horses fodder and we prepared some food for ourselves. The way I understood it was that the English were in Fouriesburg at first light.”

Jan and his compatriots were eager to engage the English. He writes that “when we saddled our horses our acting commander and his brother stopped us from returning to the English. We continued on and stayed on the farm of Mnr M. Heyns for a few days.” The English were in hot pursuit and he writes that on 28 July “we had to abandon our position.”

“The English engaged us with canons and we took new positions after about half an hours riding. The morning began violently. Our gunner could not return fire as he was pinned down under English fire. A short while after this, the attack with rifles started and continued to nightfall. Two of our men were wounded and one was killed. At this time we were very hungry. We were instructed to abandon our positions and move further. We were at this point not far from the kraal and we pressed on to Naupoort where we spent the night. The commandant and field marshal summoned us to a meeting and informed us that further resistance was futile. The field marshal was very stern and told us that the men were tired and negotiations would follow to surrender. When we left the meeting we sang Song (Gesang) 65:1. He instructed us to take our positions. A report was sent to the English General to inform him of our plans. The English officers and our officers met to negotiate. The English General insisted that the surrender had to be unconditional. Many Boers made sure that they could get to Naupoort on this day. We were completely surrounded by the English. The officers agreed to the total surrender and thought that we would be allowed to return to our homes and personal property. We, however, got away from all this with absolutely nothing (completely naked).” (JW Kok War Diary) Jan was 20 years old when this happened.

On 28 July Jan notes in his diary that the commando, under the leadership of General Marthinus Prinsloo, decides that it is not worth fighting any further since the Boers are heavily demoralised. They ask the British to negotiate a surrender.

The formal surrender happened on 30 July 1900, but Jan and his fellow Boers laid down arms on 31 July. On Monday 31 July 1900. Jan writes: “We have our weapons deposited on the surrender of General Prinsloo to General Hunter.” On this day he notes, “a time of new experiences and disappointment, for sure.


Photo courtesy of Dirk Marais. Boers surrendering at the Brandwaterkom (4)

The British took their horses and oxen and issued them with new horses. These were gaunt and sickly, and they set out for Winburg, where they believed that they would be free to go home. This mistaken belief came from the misinterpretation of a proclamation by the British that if Boers were not actively fighting and they pledge not to participate in the war, that they would be allowed to return to their farm and continue with life. It did not apply to men who surrendered during active combat as was the case with the surrender in the Brandwater Basin.

Jan, unaware of the fact that he would not be allowed to return to their farm Kransdrif in the Windburg district looked forward to being reunited with his family, having a proper meal prepared by his mom and sleeping in his own bed again. On 01 August 1900, he writes, “We continue towards Winburg and overnight at Fouriesburg. The treatment is everything but pleasant.” Despite the bad experience of the campaign, the subsequent surrender and the homeward journey, the certain expectation of imminent release must have been a great source of comfort and encouragement.

The photo of Cronje’s men at Modderrivier would have been the same image of Jan and his comrades. Photo supplied by Dirk Marais.

On 03 August 1900, they arrived at Slachtersnek. Many of the horses issued by the British at their surrender, by this time were either dead or in such a poor condition that they could not go any further. They finally arrived in Winburg on 09 August 1900. They were greeted by women welcoming them from the side of the road and Jan was reunited with his family and friends.

They wrongly expected to be released the following day, on the 10th. The reality dawned on them on 10 August 1900. Early in the cold winter morning when nighttime temperatures in Winburg can drop to – 3 deg C with icy winds, instead of being released, their expectation was betrayed as they were herded onto train trucks. At exactly 6:00, the train departed for Cape Town to an uncertain future. He later wrote in his diary about that day: “It was clear to all how the Boers (Afrikaners) experienced events of that day with the greatest disdain and sadness (afsku en smart).”

He describes 11 August 1900 as an awful day. Icy winds blew in from the north and they choked in the dust. The train stopped for a short while and children and the elderly were escorted off the train and sent home. At 2:00 in the afternoon, they continue to journey to Cape Town. The trip turns into an ordeal as they receive no food and at the many small towns along the route, the English soldiers enforce an instruction that there was to be no communication with other Boers. When the train stops at Worcester, Boers greet them with food parcels. At Paarl, young ladies force their way past the guards and hand the soldiers food parcels and addresses. The Boers who congregated at the station gave them an unexpected send-off.

As the train started to depart, a few voices started to sing very tentatively.

"Raise, burghers, the song of freedom
and our own existence as a people.
Free from foreign bonds,
Holds our small community
founded on order, law and justice
Rank among the states
Rank among the states."

As the train wheels gained traction, more joined in. The prisoners recognised it instantly! It is their national anthem. Sung in Dutch! The few initial voices joined by every proud Boer on the platform.

"Even though our land has a small beginning,
we step into the future with courage,
our eye fixed on God,
Who does not shame who builds on Him
and trusts in Him as a fortress
that does not yield to any storms
that does not yield to any storms"

Through the Paarl mountains, a crescendo of voices rose, the National song of the Orange Free State! Pride filled the souls of prisoners! Suddenly they felt pride again as it dawns on them that they were part of something bigger! Even in the former Colony of the Cape, they have brothers and sisters! A bond binds them that cannot be broken by the Imperial forces!

"Look down in mercy
on our President, o Lord!
Be Thou his recourse
The task that rests on his shoulders
may he fulfill with loyalty and eagerness
to the benefit of people and state
to the benefit of people and state

Protect, o God, the Council of the land
Guide it by your Fatherly Hand
Illuminate it from above
So that its work may be sanctified
and may serve to bless
fatherland and citizenry.
fatherland and citizenry."

Train truck after train truck left the station. The hearts of the burgers warmed! Their spirits, upright! Proud! Strong!

"Hail, thrice hail, the beloved State,
the People, the President, the Council!
Yes, may flourish at our song
the Free State and its citizens.
great in virtue, free of stains
for many ages to come!
for many ages to come!"

It’s a short ride to the Cape Town station where they arrive at 6:00 p.m.

From the station, they were transported to Green Point. He later remembers that “the Malaaihers (Malays?) and bastards (colourds?) were standing both sides of the street and mocked us all the way.” He described the experience in Cape Town in his diary as “intolerable!” The scene from their departure at Paarl repeated itself at Green Point. The inmates welcomed them with the singing of the national anthem of the Republic of the Orange Free State. It reverberated through the camp! They were sad, disappointed, disheartened, but Jan is reunited for a moment with his dad and his brothers who surrendered with Cronje at Paardenberg. Unlike his dad who would serve the rest of the war as a POW in Cape Town, Jan, along with most of the men who surrendered at Brandwater, including Gen Roux, the man whom De Wet placed in charge of the forces when he and the Government broke out boarded the ship Dilwara on 15 August. On 18 August they left Cape Town and stopover in Simonsbaai (Simons Town).

On 21 August they arrived in Durban. Aboard they were tortured by an infestation of fleas. They left Durban on 22 August. On 30 August, they anchored at the “Chysellen.” Here they were allowed for the first time to buy some fruit, “12 bananas for 6 “pence.” Jan later drew a map depicting the voyage to Ceylon.


A map, drawn by Jan Kok, of their journey to Ceylon.

On 8 September they arrived in Colombo Bay. From here they travelled 160 miles by train and arrive eventually in Diyatalawa.


At the POW Camp, he was assigned to Hut 54. On 24 March 1902, he wrote a letter to his mom. Below is the salutation and date of the letter. I attach the complete letter below in the notes.

JW Kok1.1 (ABW POW)

The letterhead of a letter Jan wrote to his mom from his Hut 54.

In later years I received communication from Radie Ferreira, whose grandfather was also taken captive under Gen. Prinsloo. He was the dominie (pastor) at Koppies. In his letter to me, he said that he had in his possession a bundle containing all the publications of the Christian newspaper, “Strevers” (probably the only copy in existence), which was circulated in the POW camp at Diyatalawa. In an addendum to the bundle are the names of 600 members of the “Strevers.” He writes: “When I opened it to see if the name of your great grandfather was there, the bundle fell open at Branch Vb and the first name, right at the top, was that of JW Kok, Hut 54, from the farm Kransdrift, Post office Winburg and a member of the Winburg congregation.” (private correspondance) (In die gebinde bundle met uitgawes van die Christelike tydskrif “Strevers”, (ek glo die enigste eksemplaar wat bestaan), wat in die Diyatalawa krygsgevangene kamp uitgegee is, is `n aanhangsel met die name van 600 lede van die “Strevers”. Toe ek dit oopmaak om te kyk of jou oupa se naam daarin is toe val die boek oop by Tak Vb en die eerste naam heelbo is Kok J.W., Hut 54, Woonplaats Kransdrift, Poskantoor Winburg en Gemeente, Winburg.)


Jan (JW) Kok in front of his hut 54 in Ceylon.

On 16 September a fellow inmate and an ordained minister, Ds. C Ferreira preached to Matt. 8:12, “But the children of the kingdom shall be cast out into outer darkness: there shall be weeping and gnashing of teeth.” That afternoon Ds. Postma preached from Luke 18:10 (probably up to verse 14). On that day they were very upset that the “koelies” (a derogatory but common term for people of Indian descent) worked on that day, a Sunday as if it was any other day. Ds. Postma’s reading deals with that judgemental attitude towards others who do not observe and worship in the same way as they do.

He writes on 22 September that he and Gert van de Venter from hut 48 started a “Zingkoor” (a choir). He attended bible study at hut 63 where Ds. Roux spoke. It is safe to assume that this is the same Ds Roux who was in charge of the forces at Brandwater before he was voted out in a very suspicious way in favour of Gen Prinsloo who immediately surrendered to Gen Hunter.


Photo courtesy of Nico Moolman. A Boer POW in Ceylon (Shri Lanka).

For the young men in the camp, this was a time of great reflection and soul searching. On 1 October, he writes that “as I reflect on the past year and what happened to me, I cannot say anything else but that the Lord helped me through it all and that he can not but thank Him for all that He has done for me.” It is interesting that he named his son, years later, Ebenhaezer, meaning “God helped me all the way and brought me to this place.” He never told my grandfather why he named him Eben. It was not a family name and must have been done deliberately in a time when conservative farmers gave their children the names of their parents or grandparents. From this entry in his diary, I can see how important this thought was to him and, especially in Afrikaans, the wording is similar to the words used in the bible from where we get the meaning of the name, Ebenhaezer. I suspect that in naming his son Eben, Jan was celebrating God’s faithfulness by allowing him to return and have his own family.

There were also ministers in the camp who used Sunday school for a time to criticize the fact that they laid down arms. Ds. Roux accused them of being selfish when they surrendered and said that they were only feeling sorry for their horses and were homesick.

He spends lots of time attending bible study and Sunday school. On 3 January, when a school was started, he attended. On 7 January he mentions that there was a mission prayer meeting and he starts to attend a missions class.


Boer prisoners of war at the Sunday service in Diyatalawa camp on Ceylon. Post and photo by Dirk Marais

All the photos from Diyatalawa are grouped in one album: Diyatalawa.

His grandson, Ds. Jan Kok (my uncle), wrote a dissertation when he completes his studies as a Dutch Reformed minister, about the development of missionary zeal in the POW camps and indeed, many of the POW’s returned home to become missionaries. This was later published under the title “Sonderlinge Vrug” (special or unusual fruit).

Jan became one of the founders of the “Zuid-Afrikaansche Pennie Vereniging” on 1 June 1902. The goal of the organisation was to promote the missionary course and through this, to expand the Kingdom of God. On 31 July, as Jan surrenders and is taken POW, Wright Harris is still very much part of the siege of Mafikeng and writes in his own diary, “Called out to wait for the Boers at daylight. Ordered not to start.” 1 August, Wright notes, “Starting out for Mafikeng. Passed Boer trenches.

He survives the campaign, but his health deteriorates. He suffers horrible bouts of severe illness. His Christian faith sustains him through everything, like Jan Kok in the Diyatalawa camp. Wright also continues to attend church parades, tent meetings, bible readings, and prayer meetings. I wonder if he could have imagined that on the Boer side there were men with much the same commitment and a common experience of faith with him.

In early October, as Jan was getting used to life as a prisoner of war, Wright Harris contracted deadly typhoid fever. He was taken to hospital where he lay for weeks, delirious and close to death. He was so severely sick that he later becomes convinced that his eventual recovery was a miracle. As soon as he has sufficiently recovered, he was sent back to Australia and arrived in Melbourne in early February 1901.

Jan (JW Kok and friends

Jan (JW) Kok and his bungalow mates. He is back row, 1st from the right.

Wright, deeply committed to his faith, undertook a year of church work in New Zealand, following the war. Jan was eventually released on 5 December 1902 and returned to South Africa on 27 December.

Followng the War

There is a deep belief among the young men at these camps that a reason for the war was that they did not do everything in their power to spread Christianity among the native African tribes. It was in a way, God’s judgment upon them for their inaction. It is therefore not surprising that after their homecoming, Jan enrols in the Missionary Seminary of the Dutch Reformed Church in Wellington. The collective Boer nations had matters to resolve that, in their interpretation of events, brought about such devastation on their land, and it is completely understandable and commendable that this became the passion of Jan’s life. Jan was confirmed in March 1906 in a mission church in Heilbron.

Wright did not have a nation to save and without the spiritual issues that plagued the young Boer-men, focusing on building his own life. He was ready to do whatever his hands found to do. Events in his life would steer him, not to full-time church ministry, as was the case with Jan, but to a life of business and bacon curing.


Probably through the Methodist church at Scoresby, he met John and his daughter, Janet Weetman. William Haine ran a butter factory in Kennedy Street, Castlemaine. He also ran a bacon company part-time as the Castlemaine Mild Cured Bacon Company, to earn additional income. Haine and Weetman agreed with John and Janet to take over the running of the bacon side of things and Weetman roped Wright Harris in to assist them. The three arrived in Castlemaine in 1905 and started the Castlemaine Bacon Company in a room in the butter factory. Together with John Kernihan they processed five pigs per week. John Kernihan and John Weetman were experienced craftsmen. Kernihan employed Weetman years earlier in his own bacon company in Northcote but lost his business during the depression of the 1850s.

Wright and Janet eventually married on 18 April 1906. John Weetman passed away on 28 March 1922 at which time Wright and Janet acquired the company and the land the factory was built on. So started a long and prolific history of the Castlemaine Bacon Company under Wright Harris’s name.


Back in South Africa, Jan remained faithful at the congregation in Heilbron for 39 years until his retirement in 1945. My uncle, Oom Jan Kok, who was named after his grandfather, followed in his footsteps and became a pastor in the Dutch Reformed Church. He faithfully serves in the Moedergemeente, Warmbad for most of his life. He tells an interesting story that when he was christened, this was done in the “black church” where his grandfather, and the man whose name he received, was the pastor in Heilbron. In those years this was of course not permitted under the Apartheid Laws. My uncle, Jan, needed a “doopseël” (baptismal seal) for some reason and it was eventually found at the “white church” (Heilbron-South) where his grandfather must have registered it.

I, in turn, am named after my grandfather, Oupa Eben Kok, and was destined to follow in the footsteps of my great granddad and uncle to become a pastor. My full name is Ebenhaezer Kok van Tonder so that I could carry the Kok name with the name given by Jan Kok to his son. During a year I spent in the USA after my own time in the South African Army (1988 to 1990), I returned to South Africa with a commitment to pursue a career in business. Bacon curing became my life! (2)

It was in researching an article on famous bacon curing companies from around the world that I came across the story of the Castlemaine Bacon Company and the link they have with South Africa. Since the founding of the company, our growth has been meteoric, much like Wright Harris’ Castlemaine Bacon Company. The Harris family now stands and looks back at a company that they eventually sold and they have in a sense completed the full circle, a road that we are still excited to be travelling and in a sense, continue to follow in their footsteps.



The great story of bacon curing is, from the beginning to the end, a human story. It took the best of humankind over thousands of years to create a dish that mimics natural processes that are part of human metabolism. The story of bacon curing is our own story in a very personal way. It is a science and an art – human culture at its best. Telling the story is telling our own personal stories. They are inseparable.

On Saturday morning I was standing in our own dispatch area, telling Oscar about this article and my attempts to make contact with the Harris family. The commitments, disciplines and great lessons from the words of John Harris and the inspiration we can draw from them.

As humans, we identify patterns, we learn, evolve and we connect. Looking at our own experience in Woody’s Consumer Brands fills Oscar and me with a deep gratitude and we take courage from the men and women of the Harris family with their remarkable heritage which is so close to our own. Bacon curing brings together some of the greatest stories on earth!


Graham Tonkin with sausages.

For a full discussion of events at the Brandwater Basin, see the next chapter, The Life and Times of Jan W Kok.

(c) Eben van Tonder

Further Reading

Lord Lansdowne at the War Office (1895-1900)


(c) eben van tonder

Bacon & the art of living” in book form
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(1) The Age, Melbourn, Victoria, Australia, 29 November 1899 reported in an article entitled “How the Boers Go to War”, The Boer process of going to war is simple enough. They have no clothes to change, no uniforms to don. They fill their bandolier, or cartridge belt, put a piece of biltong in their pocket, mount their horse and ride off. Nothing could be more simple. Biltong, it should be explained, is a sun-dried version, shredded into strips and wonderfully nourishing and sustaining. The Boers when out in the field, live on it for weeks at a time, and apparently thrive thereon. . . Everything is left to chance, and it is truly wonderful how they manage to escape all manner of horrible dangers. If they get wounded they hie them to the nearest farmhouse, where they are tended until they are well. If they get shot, – well, it is the will of God – their friends bury them and it is all over.

Practically every Boer is mounted, and although they have no regular constituted regiments, or, indeed any formal battle formation, they join together in what are called “commandos.” These are the aggregate collection of farmers and their sons from one particular district of the Transvaal, gathered together in a more or less heterogeneous mass, and under the nominal leadership of the veld cornet or the commandant of that particular district.” (The Age, 1899)

(2) I fell in love with Chemistry and in my mid 30’s decided to enter the world of food manufacturing. In 2008, Oscar Klynveld and I created Woody’s Consumer Brands (Pty) Ltd. with the ambitious goal of selling the best bacon on earth. Oscar himself is the son of a Dutch Reformed minister with deep religious convictions. I always loved writing and storytelling and when I discovered that the field of meat science is replete with amazing untold stories, I start a blog where I feature some of these amazing stories.

(3) Afrikaans: Boere-krygsgevangenes by die sondagdiens in Diyatalawa-kamp op Ceylon.

Hierdie gevangenes was hoofsaaklik van die Brandwaterkom, Oranje-Vrijstaat, onder Genl. Prinsloo afkomstig. Marthinus Prinsloo se oorgawe in die Brandwaterkom was ‘n vername terugslag vir die Boeresaak in die Tweede Vryheidsoorlog. Op 12 Januarie 1901 het sowat 630 krygsgevangenes met die Catalonia uit Kaapstad gearriveer, benewens die sowat 5 000 wat reeds in Ceylon was.

Genl. Jan Hendrik Olivier staan byna regs, middel, en di. Petrus Postma (met bybel, en aldaar bekend as “the fighting parson”) van Pretoria en Paul Hendrik Roux van Senekal staan sy aan sy in die middel van die foto. Eerw. Roux van Bethlehem en di. George Murray van Oudtshoorn, Dirk Jacobus Minnaar van Heilbron en George Thom van Frankfort sou ook in hierdie kamp onder dieselde omstandighede as ander gevangenes bly.

English: Boer prisoners of war at the Sunday service in Diyatalawa camp in Ceylon, who were mostly taken captive at the Brandwater basin, Orange Free State, under general Prinsloo. Prinsloo’s surrender was a major setback for the Boer cause during the war. Reverend Petrus Postma from Pretoria and Paul Hendrik Roux from Senekal stand side by side just right of centre, and general J.H. Olivier is visible at the middle, right. One caption to the photo was as follows:

The Boer Prisoners at Service in Ceylon. The prisoners are guarded by the King’s Royal Rifles, under Colonel Gore-Brown, Colonel Vincent being Commandant and Colonel Jesse Coope in immediate charge of them. Temporary hospital huts have been erected and brightened with pictures and illustrated papers, and officials of the local branch of the Bible Society have distributed Bibles and portions of the Scriptures in Dutch. These were welcomed and specially acknowledged by a letter of thanks by a prisoner known as “the fighting parson [Petrus Postma].” Colonel Jesse Coope, who is very popular, fosters productive manufactures and artistic activity among the men, disposing of their work through an agent. Tanks for the storage of water being required, the prisoners were invited to volunteer for the work at a reasonable rate of pay, and many availed themselves of the offer. The population of Ceylon does not exceed 6,000 [Europeans?], and the settlement of the Boer prisoners has had a wholesome effect, not only on themselves but on the Cingalese. The minister who is officiating (in the above photograph), is the “fighting parson” alluded to – the Rev. Mr Postma – and General Roux stands beside him. Olivier can be identified nearer to the right margin of the picture and several rows further back.

Source: Post and photo by Dirk Marais


OP 30 Julie 1900 het 4 314 Boere op Oorgaweheuwel (Surrender Hill) op die plaas Verliesfontein naby die huidige Clarens hul wapens neergelê. Die Britte het ook 3 veldkanonne, 2 800 beeste, 4 000 skape, 5 500 perde en 2 miljoen patrone in die Brandwaterkom gebuit. Dit was ‘n geweldige terugslag vir die stryd teen die Britte.

LORD ROBERTS, opperbevelhebber van die Britse mag in Suid-Afrika, was met sy vertrek in Mei 1900 uit die Vrystaat nie baie bekommerd oor die Vrystaatse mag onder aanvoering van genl. C.R. de Wet nie. Hy het geglo sy mag sou die Vrystaters in bedwang hou.

Einde Mei en begin Junie gebeur egter ‘n paar dinge in die veld wat sy houding drasties laat verander. Op 31 Mei verslaan die Vrystaatse mag die Yeomanry naby Lindley. Twee dae later by Swawelkrans, buit De Wet 56 waens wat vir die Engelse in Heilbron bestem was. Op 7 Junie behaal De Wet ‘n verdere oorwinning oor die Engelse by Roodewal. Dié nederlae het Roberts laat besef dat hy ‘n fout gemaak het om die Vrystaters te onderskat. Op 14 Junie gee hy uit Pretoria aan sy bevelvoerders opdrag om De Wet teen die berge in die Oos-Vrystaat vas te druk en te vang. Hy het gehoop, maar nooit gedink dat hy binne twee maande amper die helfte van die Vrystaatse mag sou kon vang nie.

Genl. R. Buller moes in Standerton keer dat die Boere noord vlug. Lt.genl. sir L. Rundle, wat ‘n sterk verdedigingslyn tussen Winburg, Senekal en Ficksburg beman het, het die suide geblokkeer. Genls. R.A.P. Clements en A.H. Pagel het die Boere van Lindley af oos in die rigting van Bethlehem aangeja.

Lt. Genl. sir A. Hunter, wat in bevel was van die dryfjag op die Boere, het van Transvaal via Frankfort en Reitz in die rigting van Bethlehem opgeruk.

Ná die Slag van Bethlehem op 6 en 7 Julie 1900 het De Wet en die Vrystaters dus eintlik geen keuse gehad as om suid in die rigting van Fouriesburg en die Brandwaterkom te trek nie.

Op 8 Julie 1900 bevind die hele Vrystaatse mag, behalwe hoofkmdt. F.J.W. Hattingh met die Vrede- en Harrismith-kommando wat die bergpasse oppas, hulle in die Brandwaterkom. Ook pres. M.T. Steyn en lede van die Vrystaatse regering was hier.

(c) Dirk Marais

My Oom Jan Kok het tydens ‘n biduur die volgende van sy oupa en my oupagrootje vertel.

Letter from Jan (JW) Kok to his mother from the POW camp in Ceylon.


(5) A few photos from my visit to Castlemain

War Photos Connected to Wright Harris

In the NSW Imperial Bushmen camp, South Africa, 1900. AWM A04298.
Marching down Collins Street, Melbourne before departure for South Africa.
At the Langwarrin Camp.
The Victorian Contingent Taking Horses Aboard
Members of the Third ‘Bushmen’s’ Contingent at the Langwarrin Training Camp outside Melbourne, prior to departure for South Africa.
Departure of SS Euryalus
People jostled on Queen’s Wharf when the Lucinda arrived with members of the Queensland Imperial Bushmen home from the Boer War

– Further Reading

Anglo Boer War: Australian Units

The Australian Boer War Memorial

Australian Bushmen ambushed on the road to Elands River, By Robin W Smith

War and Australia – Boer War


I liberally quote and use information from Bringing home the bacon: a history of the Harris family’s Castlemaine Bacon Company 1905-2005 / Leigh Edmonds. Monash University. The photo of Wright Harris, this source.

Murray, P. L.. 1911. Official Records of the Australian military contingents to the war in South Africa. Albert J. Mullett, Government Printers.

The Philadelphia Inquirer, Philadelphia, Pennsylvania, 6 May 1900, page 3

The Age, Melbourne, Victoria, Australia, 29 November 1899, page 5.

All information and photos of JW Kok supplied by Jan Kok in private correspondence.

Photos of the Harris family and Castelmain Bacon Factory from Leigh Edmonds, 2005, Bringing Home the Bacon, Monash University.

Salt in Bacon & the Art of Living

Salt in Bacon & the Art of Living
By Eben van Tonder
21 June 2021


In Bacon & the Art of Living, I dedicate three chapters to salt. It remains one of my favourite study subjects. The truth is that I only scratched the surface. It is a subject that I will return to often and I am planning to expand on Chapter 10.12, The Salt of the Land and the Sea. Here I present the three chapters for those who are interested in a more thematic study.

Chapters on Salt

Further Reading

I have written far more about the subject than is presented in my book on bacon. Those who are interested in exploring this fascinating subject further are directed to the following articles, all of which I used in compiling the three chapters listed above.

Please make contact!

Any contributions or comments can be directed to me at:


Phone Number and Whatsapp: +27 71 545 3029

Cape Town

South Africa

The Complete History of Bacon.

Image Credit

The Charc’Tank

Hey there!

Join Gil and Eben every week in the Charc’ Tank where we talk meat!

Don’t expect an academic discussion. Having said that, we are not scared of scientific inquiry!

We talk informally about that which we love: meat!

We dont always stick strictly to a point by point script or even to any particular subject even though we broadly thread every discussion around a central theme.

What you get is:

  • Informative
  • Interesting
  • Fun
  • Relevant

From the tank:

(list of all podcasts)

#1 – What is Water Activity, and how does it relate to meat curing?

Further Reading: Water Activity

-> Water Activity and Moisture Sorption Isotherms

#2 – Microbes: Part 1 – Bad bacteria and hygiene in the curing kitchen


Further Reading: Microbes

-> Microbiology

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About us.

Gil started his meat journey in 1978 when he was just five years old. The first piece of “furniture” he bought with his own money when he moved out of his mother’s home in 1994 was a WEBER Kettle BBQ.

For the past 17 years, Gil has been curing meats as a hobbyist and commercial curesmith.  In 2019 Gil, with his family, moved to Poland, where he is now focused on building a digital media business promoting the curing of meat.

Eben created Woodys Consumer Brands in 2008 with Oscar Klynveld which grew to SA’s largest 3rd party bacon producer. He left Woodys in 2018 to focus on fine emulsion sausages and other interesting meat research projects. He writes extensively on the meat industry and continues to works in the trade as an independent consultant. He lives in Cape Town.

! Read more

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Meat Emulsions – A Roadmap to Investigations

This is the Index Page for all work related to MDM and Blended Ham Products.

Meat Emulsions – A Roadmap to Investigations

2 October 2020

In April this year, I decided to put everything I thought I knew about fine meat emulsions aside and to start from scratch. This was a very hard week where nothing worked the way I wanted it to work. For a large part, I was flying on autopilot, disregarding my personal extreme disappointment with the world NOT working the way I thought it must work. For several days I was in the test kitchen from first thing in the morning and was the last person to leave. What emerged at the end of the week was not an answer, but a roadmap to the answer.

I went for a run when I got home and the enormity of the breakthrough dawned on me. Let me recap what I decided in April when I embarked on this journey. I questioned everything!

What is the role of equipment? What are starch-, soya-, rinds- and fat emulsions and why create it or use it in the final meat emulsion? What exactly are TVP and the various isolates? What is a modified starch and what are the differences with native starches? What is a food gel and what characteristics are required under which conditions? What is the role of meat proteins in gelation? What is an emulsifier and what is a filler? How did these enter the meat processing world and what has been the most important advances? What is the legislative framework? What is the role of time, temperature, pH, pressure, particle size on these products in isolation and synergistically, in a complex system? What is the role of enzymes in manipulating these? What are all the possible sources of protein, starches, fillers and emulsifiers? How do we enhance taste? Firmness? etc.

The subject is clearly stated by Gravelle, et al. “Finely comminuted meat products such as frankfurter-type sausages and bologna can be described as a discrete fat phase embedded in a thermally-set protein gel network. The chopping, or comminution process is performed under saline conditions to facilitate extraction of the salt-soluble (predominantly myofibrillar) proteins. Some of these proteins associate at the surface of the fat globules, forming an interfacial protein film (IPF), thus embedding the fat droplets within the gel matrix, as well as acting to physically restrain or stabilize the droplets during the thermal gelation process. As a result, these types of products are commonly referred to as meat emulsions or meat batters.” (Gravelle, 2017) I love this concise description and in it is embedded a world of discovery and adventure.

A road-map emerged. It is different from NPD in that in this stage of the game, I assume that I know nothing. I seek to learn as much as possible through experimentation and carefully selected collaborations, done in such a way that confidentiality is not an issue. I assume that I don’t know enough and that the information I have been given over the years may not have been the most correct or complete information. I assume that if I understand the various chemicals and equipment pieces better than most people, I should be able to arrive at answers that others are not able to.

My first task was to set out the framework for investigations. The new investigative techniques that became clear to me this week will only be effective within the right philosophical framework.

Test, test and, when you had enough, test some more!

Develop a way to do rapid testing of various combinations or products in isolation. Test per certain pH, temperature, particle size, etc. Test and test and test some more. Remember to keep careful notes with photos.

Find Solace in the wisdom of the old people.

Often, the greatest food innovations emerge out of an understanding how things were done hundreds of years ago. This is the basis premise of The Earthworm Express.

List Protein Sources

Make a list of all protein sources, their protein content, fat, fiber and other characteristics. What is the state of the proteins? Denatured? Damaged? Get samples and test.

Develop Rapid Test’s

Develop rapid test techniques which are quick, inexpensive and accurately mimics processing conditions. Fed up and frustrated with the restrictive and expensive nature of the test kitchen set-up, it was the realization how to do this that was my biggest breakthrough this week.

Don’t Trust Ingredient Comp’s.

Seek advice, but remember that staff from spice companies will tell you whatever they have to tell you to sell their particular product which may or may not be what you are looking for.

Understand your Equipment

Take the time to understand the different pieces of equipment who purports to fulfill a certain function and compare the results by talking to different production managers who use these equipment pieces. Is smaller better? Heat generated? Damage to proteins?

List binders/ emulsifiers

List all possible binders/ emulsifiers / fillers and test. Get samples and test.

Record and photograph everything!

Record everything. Inclusion (dosage), pH, temperature, reaction time, processing steps. Keep meticulous photo records.

Build an international network of trusted friends

Seek out the advice of people you trust when you run into a dead end. I find it best to have such a network of collaborators across the world. Pick the right peoples brains!

There is ONE least cost formulation for every situation.

I have come to the conclusion that it is merely a matter of data manipulation to arrive at the one ultimate “least cost” solution for every product, in any particular set of circumstances.

Separate the steps and logically group chemical reactions.

Group chemical reactions together and separate steps to achieve optimal results, thus creating different emulsions to be blended together in the final step.

Index to Articles and Notes

-> Chicken Meat – Thawing, Breading, Cooking, Browning

-> Collagen Marker: Hydroxyproline

-> Counting Nitrogen Atoms – The History of Determining Total Meat Content Before we get down to business, I examine the history of the development of the concept of Total Meat Equivalent and the equations which are laid down in legislation.

-> Emulsifiers in Sausages – Introduction. Understanding the role and chemistry of non-meat emulsifiers, extenders and fillers is currently widely used in South Africa.

-> Experiential Substitutes for Chicken MDM

-> Hot Boning in America First step towards a better understanding of the binding of proteins to each other and water.

-> MDM – Not all are created equal! Starting to understand the base meat material used in fine emulsion sausages in South Africa.

-> Notes on Alginate

-> Notes on Proteins used in Fine Emulsion Sausages

-> Notes on Starch. Characteristics and composition of this often used gelling agent are discussed.

-> The Origins of Polony The origins of polony informs us a great deal in its composition.

-> Poultry MDM: Notes on Composition and Functionality Here we start our detailed consideration of chicken MDM.

-> Protein Functionality: The Bind Index and the Early History of Meat Extenders in America The first consideration is the fact that different meat sources, and different parts of the carcass, have different binding functionalities. Here I also develop the history of binders, fillers and meat extenders in America and the birth of the analog product.

-> Special Projects 3

-> Soy or Pea Protein and what in the world is TVP? Here we start to learn about the functional properties brought to the fine emulsion by soy, pea protein and TVP by first understanding exactly what they are and how they are produced.

Over the next years, I want to make this approach part of my daily routine. I am interested to work with collaborators on various aspects of the project.

Let’s build our understanding together.

Cape Town, South Africa

Denny’s Beef Style Mince vs. Frey’s Veggie Mince

Product Comparison
By Eben van Tonder
24 August 2020


Meat products fall in the following three categories.

Pure Meat Products is where every ingredient except the spices come from an animal carcass.

Meat Analogues are starches and soy, grains and cereals which are made so that it tastes like meat but contains no part of an animal carcass. The question comes up as to why would a vegan, for example, who does not want to eat meat, buy a product disguised as meat, but which, in reality, contains no meat? Pure meat and meat analogues are therefore two opposing and extreme ends of the spectrum.

Meat Hybrids is the middle of the two and combines meat and plant-based protein, essential for the purpose of achieving a cheaper product. There is something deceptive about this class of products since it is often designed to mislead as to the real nature of the products (I say this, despite the label declaration, which is often still enigmatic to consumers). They think it’s meat, but it contains a percentage of non-meat fillers. This is almost always done to reduce the price of the product, which, in a country like South Africa, is not necessarily a bad thing. Affordable food, where “affordable” is relative to the income level of the consumer, is a very important consideration. It must also be stated that for the most part, large producers of this kind of products do not add as fillers and extenders, anything except high quality, acceptable and healthy products such as soy in the meat to extend it.

My personal preference is clear. I prefer pure meat products mainly based on taste and, to a lesser extent, on matters such as allergy which relate to health in that some of the fillers may be allergens. Taste of pure meat products can, in my personal opinion, not be matched in taste, firmness, mouthfeel, or any other organoleptic characteristics (the aspects of the end-product that create an individual experience via the senses—including taste, sight and smell).

Meat Hybrids I can understand, living in Africa where there is a long tradition of honouring every scrap of meat. My main issue is with meat analogues.

It was with this background that I was intrigued by Denny Mushroom’s range of meat substitute products they recently launched. When I saw it being advertised at our local Spar I immediately went looking for it, but due to its popularity, only the mince was left. My wife and I decided to compare it to soy mince.

In order to do any evaluation worth its salt, we find it best to pare it against a competitor. Here is our evaluation:

The Face-off


We chose the same basic method of preparation and ingredients.

Denny Beef Style Mince


Mushrooms (75%), Oats, Onion, Seasoning (Yeast Extract [Garlic, Sugar], Salt, Dextrose, Caramel colour, Silicon dioxide, Herbs & spices), Maize, Vegetable fat (Sunflower seed, Palm kernel, THBQ, Sodium alginate, Calcium sulphate, Dextrose, Phosphate, Modified Starch), Psyllium husk, Beetroot, Ascorbic acid, Flavouring, Guar gum, Potassium sorbate. 

Phrases like “meat alternative” and “100% Vegan Superfood” removes all doubt – it contains no meat.

The product looks like mince and it is obvious where the name comes from. I have a bit of an issue with the “Beef Style” part of the name since it creates an expectation that it will taste like beef. The ingredients list makes it clear that there is no beef in the product.

Final Evaluation

At first, I am disappointed by the “Beef Style Mince” when I realise that it does not taste like meat at all. My problem with it was, however short-lived when I took my second bite! The taste is “refreshing!” It is unlike anything I had before and is delicious! It stands on its own as a well-formulated product! Sure, it tastes nothing like mince, but it still is exceptional!

Minette and I both noticed that it binds well, meaning that it mushes into a meatball (well, not a meatball 🙈🙈🙈 but you get my point) 🤣 This characteristic opens up a world of possibilities for the chef and is also distinctly different from minced meat.

The manager at Spar told me that the mince is not selling as well as the rest of the range. In my personal opinion it will be a pity if, for commercial reasons, the line is killed.

I understand why they would never go there, but is ripe for inclusion in a food hybrid formulation. A thought for the future as a different brand name with a unique positioning will do well with it. It scores a well deserved 8 out of 10 for a refreshing taste, its originality and the overall product formulation! Hats off to the development team!

Veggie Mince of Frey’s


The product comes in an inner pack with gravy, but right from the start, one can see that it looks far less appealing than Denny’s product. The ingredients are:

Vegetable Protein (Soya, Wheat (Gluten)), Flavourings (Onion, Pepper, Maize Starch, Anti-caking Agent (E551), Savory Flavour), Vegetable Oil (Sunflower Seed), Wheat (Gluten) Flour, Potato Starch, Plant Fibre, Maize Starch, Thickener (Methyl Cellulose), Ground Coriander (Sulphites), Salt, Onion, Mustard, Colourant: Caramel IV

Final Evaluation

Similarly to Denny’s, it positions itself squarely for the vegetarian market with no meat. The taste was unfortunately such that I could not take a second bite. We threw it all into a bag and in the dustbin. It scores a disappointing 2 out of 10.

In contrast to this, I got up at 2:00 a.m. this morning and sneaked into the kitchen to finish the leftovers of the Denny product!


I understand why marketers link non-meat products to meat. They believe a meat point of reference will aid them in selling the product. Life may very well prove them right. Still, it is a pity, particularly in the case of Denny who produced a unique and exceptional product which should be able to stand on its own two feet, apart from the simile to meat. Why not call it Mushroom Style Mince? or Denny Style Mince?  Whatever you call it, it is a brilliant product!


– Frey’s is a well-respected producer and there are many of its products which I love and regularly buy. The Mince is only one of them which I will rather give a miss.

– The views expressed are purely my own. The products were prepared in an unscientific way and no blind test or other evaluation was performed besides merely my first impressions upon tasting it. I advise consumers to be their own judge if they agree with me or not.

– I refer to myself as doing the evaluations for the sake of not making my amazing wife complicit in my comparisons! 🙂 Reality is that I am a very poor cook and she is in a league of her own. Her sister and she practice cooking as an art and not a way to get food in one’s stomach! Minette, therefore, prepares all the meals – exceptionally well. I only enjoy and judge them with her!

Please email me on for comments or suggestions. Feel free to comment at the bottom of this blog post!

Poultry MDM: Notes on Composition and Functionality

Poultry MDM: Notes on Composition and Functionality
by Eben van Tonder
5 July 2020


The mechanical deboning of meat has its origins from the late 1940s in Japan when it was applied to the bones of filleted fish. In the late 1950s, the mechanical recovery of poultry meat from necks, backs and other bones with attached flesh started. (EFSA, 2013) A newspaper report from the Ithaca Journal, Wed, 30 Dec 1964 is the earliest reference I can find on Mechanically Deboned Meat (MDM) in America. It reports on research done at Cornell State College of Agriculture in an article entitled, “New Egg Package, Chicken Products Are Among 1964 Research Results.” It reports that “mechanically deboned chicken meat was put to use for the first time, and improvements were in new types of harvesting machines.”

It claims that MDM based products would be available from 1964. “Late in 1964 Cornwell researchers began preparing experimental chicken products from this meat, which resembles finely ground hamburger.” It said that the new chunky type chicken bologna, was introduced in three forms: Chicken Chunk Roll, which is half chunk meat, and Chicken Chunkalona, which is 25 per cent chunks and 75 per cent emulsion.”By 1969, several American universities were working on these products, including the University of Wisconsin.

The Oshkosh Northwestern, Thu, 21 Aug 1969

By the early 1970s, the removal of beef and pork from irregularly shaped bones was introduced. Originally, the aim of MDM was to reduce the rate of repetitive strain injury (RSI) of workers caused by short cyclic boning work in cutting rooms of meat operations. A press was developed to accommodate this. The success of the approach resulted in a rapid acceptance of the principles and an incorporation of the technology across Europe and the USA.

As is the case with meat processing technology in general, despite recent developments of the process, the basic approach is still the same as the first machines that was built. Initially primitive presses derived from other types of industries were used to separate the meat from the bones, using pressures of up to 200 bar. A fine textured meat paste was the end-product, suitable for use in cooked sausages. Gradual technological improvements and pre-selection of the different types of flesh bearing bones pressed at much lower pressure (up to 20 bar) produced a coarse texture of higher quality meat that could no longer be distinguished from traditional minced meat (so called 3 mm or Baader meat).

Today, a wide variety of different products are available on the market from many different suppliers of every imaginable animal protein source. Legislation differs widely between different countries on the definition of MDM. They name and classify it differently and the astute entrepreneur will find opportunities in studying every aspect of this fascinating industry closely, especially in the maize of ever evolving legislation related to it around the world. As one country restricts its use on one front, other countries will be able to buy a particular grade or type at better rates and this will in turn open up opportunities in the buying-country’s market for new ways to use raw material which becomes available for it due to a drop in the price.

My own foray into this world took place during a year when Woody’s gave me the opportunity to spend almost a year working with companies in England. The project I worked on was high injection pork. During this time there were changes to legislation related to ground pork. I witnessed UK prices plummet on a commodity which, in retrospect, we should have pounced on, but I knew far too little about the sausage market to exploit the opportunity. My business partner in the company we founded and where neither of us are involved in any longer will certainly have a good chuckle remembering those days!

Between 10 May and 8 June 2012, at the Tulip plant in Bristol, England, we extended ground pork with 100% brine which was designed by a friend from Denmark. Brine was tumbled into the meat, heat set, chilled, frozen and sliced. Re-looking at the texture of the final product from photos I took, almost 8 years later to the day, I realise that we should have used it to create a fine emulsion for a sausage or loaves. Looking at the result of the 100% extension below, we could easily have targeted 150% or even higher. We could have landed the raw material at a very competitive price in SA if we created a fine emulsion base, extended 150% with rind emulsion added (instead of rusk) and used it as the basis for a number of fine emulsion based products at our factory in Cape Town. Evaluating what we did in Bristol, the heat setting, even in our course loaf-like product, was inadequate for proper gelation, which is clearly seen in the photos below.

All the photos related to these trails can be seen at:

The lesson for me is that in order to exploit these realities, one must grasp the functional value of the raw material, which in our consideration here is MDM, but must most certainly include other similar products not necessarily classified as MDM, MRM or MSM such as ground meat or something similar. This will lead to an appreciation of the differences between various grades of MDM and related products, which will allow processors to develop new products and increase its bottom line / reduce selling prices of others as new MDM products become available and countries adjust its legislation to regulate its use. It all begins by understanding the basic principles at work in this immense and fascinating world. We begin by looking at the basics of poultry MDM.

I use the work of JM Jones as the basis for these considerations as was published in the work edited by Hudson, B. J. F.. Related to the functional characteristics, I rely on the work of Abdullah and Al‐Najdawi (2005). They set up to investigate the effects of either manual or mechanical deboning on the functional properties of the resultant meat and any changes that might occur in quality attributes, as measured by sensory testing. They also considered the effects of frozen storage. In their study, they compared 4 treatments: treatment 1: manual deboning of whole carcasses; treatment 2: manual deboning of skinned carcasses; treatment 3: mechanical deboning of whole carcasses; treatment 4: mechanical deboning of skinned carcasses. We will refer to these 4 treatments during our discussion below.

Production Methods, Meat Quality and Nomenclature

The process of mechanical deboning involves crushing the bones and mixing with meat and skin before the bone is separated out. Inevitably, crushing of the material leads to changes in the chemical, physical, sensory and functional properties of the meat, and meat colour is a case in point. This is one of the most important meat-quality characteristics, with a strong influence on consumer acceptance of the retail product.

Groves and Knight refer to EU Regulation (EC) No 853/2004 which defines “mechanically separated meat (MSM) as the product from mechanical separation of residual flesh from bones where there has been loss or modification of the muscle fibre structure. MSM cannot count towards the meat content of products for the purposes of Quantitative Ingredient Declaration (QUID) requirements in EU Food Labelling legislation.”

Today, MDM production take place in two forms. With high pressure and with low pressure. Low pressure MSM was previously called desinewed meat (DSM or 3mm meat) in the UK and it was shown that it has a considerable amount of intact muscle fibre structure similar to some meat preparations (made from hand deboned meat or HDM) and was very different to high pressure MSM. Based on this research and analytical evidence in the literature, DSM was considered in the UK to fall within the definition of ‘meat preparations’ in EU food law rather than that of MSM. By itself, this shows the major difference between High Pressure and Low Pressure MDM.

Groves and Knight reported that “an audit by the Food and Veterinary Office of the European Commission (FVO) was conducted in March 2012 and led to a change in UK policy to align with the Commission’s interpretation that DSM was treated in all respects as MSM, including for the purposes of QUID. This has significant economic implications as the value of the low pressure MSM is considerably reduced. It is accepted that there is no evidence of any increased food safety risks associated with low pressure MSM (DSM).” It is this classification change that I refer to my own England experience in 2012 and is my case in point of focus for the international MDM trade and opportunities created by a change in legislation.

Regulation (EC) No. 853/2004 further defines different rules for MSM produced by techniques that do not alter the structure of the bones and those that do. This is based on whether the product has a calcium content that is not significantly higher than that of minced meat, for which a limit is set down in Regulation (EC) No. 2074/2005. Calcium content is therefore a method of determining if high or low pressure meat recovery is used as opposed to the health issue, which was the case, early on in its introduction on the world stage.

Their report is very educational in terms of various production methods and serves as an excellent introduction into our study. An evidence-based review MSM vs DMS For now, it is enough to identify two main classes of equipment for producing MDM, High Pressure MDM and Low Pressure MDM machines. Even though Abdullah and Al‐Najdawi (2005) do not say if the MDM used in their study was produced with HP or LP, my guess is that it is Low Pressure MDM produced in Jordan. I mailed the author to get clarity on the point since it will have a direct impact on the points of application. For now, I will assume that Low Pressure was used.

Viuda-Martos (2012), generalises more in their definition of these products. Like many authors, they see mechanically deboned meat (MDM), mechanically recovered meat (MRM) or mechanically separated meat (MSM) as synonyms to mark material, obtained by application of mechanical force (pressure and/or shear) to animal bones (sheep, goat, pork, beef) or poultry carcasses (chicken, duck, turkey) from which the bulk of meat has been manually removed (Püssa and others 2009). They state that the deboning process can be applied to whole carcasses, necks, backs and, in particular, to residual meat left on the bones after the completion of manual deboning operations.

Importantly, they highlight some of the key challenges with this class of products in that the mechanical process of removing meat from the bone causes cell breakage, protein denaturation and an increase in lipids and haem groups and poorer mechanical properties. MDM is therefore characterised by a pasty texture of various consistencies, depending on a wide range of factors. The past texture is generally due to the high proportion of pulverised muscle fibre residue, and the presence of a significant quantity of partly destructured muscle fibres. The term used by these and other authors for this loss or modification of muscle fibre structure is ‘‘destructuration”. Recovered meat is generally considered to be of poor nutritional and microbiological quality and is strictly regulated in its use as a binding agent or as a source of meat proteins in minced meat products. (Viuda-Martos, 2012)

MDM is, therefore, used in the formulation of comminuted meat products and in the creation of fine emulsion sausages due to its fine consistency and relatively low cost. It is an important raw material in underdeveloped countries, due to its price. (Viuda-Martos, 2012) Groves and Knight remind us how important the naming of a substance is and how difficult it is in the case of this class of products. It would be a mistake to see MDM, MRM, MSM or any of the other synonyms as homogeneous product names and that without delving into the details of its production, we cannot fully know its functional qualities. Each individual product, from each different supplier, at different times (depending on input raw material, which is never consistent), must be looked at carefully and evaluated on its own.

There are, however, general observations that can be made related to the overall product class. If nothing else, what follows will give us a list of questions to ask and reasons why it is important. It will further give us an appreciation of the complexity of its evaluation and manipulation and the impact it can have on the final product produced from it.

Poultry MDM Stability

In general, poultry MDM has been shown to have more constant composition compared with pork, veal and beef MDM. Considerable variations in fat and protein content occur in poultry MDM. The amount of back, wing, neck, rack, skin (or no skin) or the ratio of starting material used and type of deboning machine and settings play a major part in final product composition. Deboner head pressure was increased x 3 to increase the yield from 45 to 82%; fat content significantly reduced and moisture content increased. (Hudson, 1994) This is an interesting observation. What could have caused the decrease in fat and increase in moisture? The decrease in fat was probably due to an increase in other components such as connective tissue and the increase in moisture probably refers to unbound water, which resulted as a result of the higher pressure and bone marrow. The addition of bone marrow under higher pressure was therefore less than the increase of connective tissues.

Rancidity problems stem from the method of production. Air with increased iron because of bone marrow are the major reasons. Additional fat stems from bone marrow and skin. Phospholipid fraction, as a percentage of total lipid content, is only at about 1 – 2% in poultry MRM. Over 60% of this may be unsaturated, oleic, linoleic, arachidonic acid. These acids decrease in concentration during freezing or frozen storage of turkey meats or nuggets made from chicken MDM. This (the decrease in polyunsaturated fatty acids) may be explained by reports that chicken muscle homogenates to contain enzymes capable of oxidizing both linoleic and arachidonic acids and one was found to be stable during frozen storage, being 15-lipoxygenase. (Hudson, 1994)

Iron in MDM acts as a catalyst in lipid oxidation is well known, but -> is it haem or non heam iron that plays the dominant role in poultry? Lee et al. say that haem protein, (50% of total iron) is the dominant catalyst for lipid oxidation in poultry MDM. Igene et al. claim that “warmed over flavour” of cooked chicken meat (whole muscle) is due to non-haem iron release during heating, which is the catalyst for oxidation. Kanner et al. say that one reason why haem protein effects lipid oxidation only after heating was that catalase activity was inhibited and this allowed H2O2-activated mayoglobin to initiate peroxidation. Related to uncooked meat, these authors report an iron-redox cycle initiated peroxidation and the soluble fraction of turkey muscle contained reducing substances which stimulated the reaction. Free iron in white and red meats of chicken and turkey increases in concentration with storage time and is capable of catalyzing lipid oxidation. (Hudson, 1994)

Decker and Schanus used gel formation to separate an extract of chicken leg muscle into three protein fractions. One catalysed over 92% of the observed total linoleate oxidation. Iron-exchange chromatography of this active fraction revealed three proteins capable of oxidising linoleate. Haemoglobin was responsible for 30% of total oxidation while two components (according to Soret absorbance) were non-heam proteins and responsible for 60%. (Hudson, 1994)

“Metal ions from the deboning machinery itself and calcium and phosphorus ions from bone may act as catalysts for haem oxidation (Field, 1988).” Also, mechanical deboning of material containing skin leads to a release of subcutaneous fat that tends to dilute the haem pigments present, producing meat of a lighter colour. The same is true for fat released from bone marrow during crushing.” (Abdullah and Al‐Najdawi, 2005)

Related to the effect of the production process on myoglobin, it has been proved that manufacturing MDM “has no effect on the myoglobin contents, although it may influence the form of that pigment, thereby causing colour changes (Froning, 1981).” (Abdullah and Al‐Najdawi, 2005) Much work in this area remains.

Modification of Poultry MDM and Functional Characteristics

-> Texturing

The paste-like nature of poultry MDM limits its use. Early investigations focused on ways to “texturise” it. This can be done by adding plant protein or by various heat treatments. Sensory properties are not always what is desired. (Hudson, 1994)

One method of producing MDM products is to use a twin-screw extrusion cooker. (Extrusion Cooking) Treatment of poultry MDM alone gives unsatisfactory results. The fat content of the material is too high. Satisfactory products similar to meat loaf or luncheon meat were achieved if, as binding or gelling agents, cereal flours, corn starch, egg white concentrate or soy protein isolate were combined with the MDM. (Hudson, 1994) This begs the question as to the gelling temperature of these products.

Alvarez et al. found that chicken extruded with 10 or 15% corn starch, lipid oxidation decreased as extrusion temperature rose from 71 to 115.5 deg C. They suggest that antioxidants were produced with increasing temperature. Hsieh et al. reported that a mixture of turkey MDM (40 parts) and corn flour (60 parts) increased in susceptibility to lipid oxidation above 110°C. The antioxidant BHA (butylated hydroxyanisole) was added to the raw materials before extrusion. (Hudson, 1994)

-> Haem Removal

Haem pigments in the product impacts on product stability and in poultry MDM it has a tendency to create a dark colour in the final products. Much effort is expended to remove these pigments and so extend the range of products in which the MDM may be used. (Hudson, 1994)

Froning and Johnson showed that centrifuging poultry MDM would remove haem pigments. Washing procedures was first developed in Japan to remove haem proteins, enzymes and fats from fish during the production of the myofibrillar protein concentrate, surimi. A lot of work has been done to extend the same procedure to washing MDM. However, there are several reasons why surimi technology might not be applied directly to poultry MRM, viz:

1. Surimi is prepared from whole muscle while poultry MDM is isolated from bones after most muscle tissue is removed.
2. Poultry MDM can have considerable quantities of connective tissue in the final product, e.g. histochemical investigations have shown the connective tissue: muscle ratio of chicken MRM to be 1 : 1.2.
3. Fish mince is frequently washed during preparation, but water washing is not an efficient means of removing haem pigments from MRM.
4. Lee suggested the size of perforations in the deboner drum of fish deboners ranges from 1 to 5 mm, with orifices of 3 to 4 mm giving the best quality and yield of surimi. Poultry deboners seem to have a pore size below 1 mm and thus the particle size of the products will differ. Since the term ‘surimi’ has long been associated with the product isolated from fish muscle, it is perhaps debatable as to whether the term should be applied to the material prepared from poultry MRM.

(Hudson, 1994)

Other terms used are:

‘Washed mechanically deboned chicken meat’, ‘myofibrillar protein isolate’, (MPI), ‘isolate of myofibrillar protein, (IMP). The acronym IMP is problematic since it is widely accepted as an abbreviation for inosine monophosphate. Clearly some rationalization of nomenclature is required and perhaps a term such as ‘poultry myofibrillar protein extract’ would be more appropriate. (Hudson, 1994)

One of the earliest studies of poultry, turkey neck MDM, considered to be the darkest poultry MDM, was washed either three times in water or once in 0.04 M phosphate at various pH values, followed by two water washes. Then, the mixtures were pressed through cheesecloth to remove as much moisture as possible. The yield of paste from water-washed MRM was higher than that which had been treated with phosphate, but it had a darker colour. The researchers concluded that washing with 0.04 M phosphate at pH 8.0 provided the most efficient means of removing red pigment from turkey MDM. Froning and Niemann reported that extraction of chicken MDM with 0.1 M NaCI significantly reduced fat concentration and colour, and increased protein concentration. Others, using different washing techniques, particularly the use of bicarbonate as the washing medium, have found that either the protein content of the washed material was similar to that of the starting material, or was up to 7% lower. However, all agreed that washing drastically reduced the fat level of the recovered material. (Hudson, 1994)

Washing with bicarbonate appears to be the most efficient way of removing pigment from poultry MDM, probably due to the fact that the pH value of the slurry makes the blood proteins more soluble, there may be other factors at work to influence the final colour of the washed product. For example, Trziszka et al. found that if, following bicarbonate extraction, water washing was carried out at pH 5.5, the product was lighter than at pH 6.0, while the variable amounts of connective tissue present in the washed residue can influence the appearance of the material, as shown by Kijowski et al., who found that removal of connective tissue by sieving increased both the darkness and redness of water-washed chicken MRM. (Hudson, 1994)

The yield after washing range was 13.5 to over 62% of the starting material. Reasons for this variety may be the result of a number of factors such as source material for MRM, grinding of MRM before washing, nature of washing medium, washing time, adjustment of pH, number of washes, ratio of MDM to extractant and centrifugal force applied during separation of ‘meat’ and extractant. (Hudson, 1994)

Cryoprotectants, such as mixtures of sugars and/or phosphates, must be added for the washed material to retain its gelling and water-holding abilities during frozen storage. Washing improved the functional properties of the material – after cooking the washed MDM was more chewy, less cohesive and had increased stress values but the cooking losses from washed material were higher, probably due to the fact that ‘free’ water was absorbed during washing. The best indication of the success of the washing procedure is probably in practical terms measured by the performance of the myofibrillar complex in products. There have been a few studies who looked at this. Frozen-thawed, bicarbonate washed turkey MDM at a level of 10% reduced the fat level of frankfurters, while increasing the expressible moisture content and resistance to shear compared with control frankfurters. Scanning electron microscopy did not reveal any obvious structural differences between controls and frankfurters containing 10% washed MDM. Hernandez et al. reported – the protein paste from washed turkey MDM could be incorporated into patties at levels up to 20% without adversely affecting sensory quality. Trziszka et al. reported that up to 50% of the ground chicken meat in hamburgers could be replaced by carbonate-washed turkey MRM without reducing the acceptability of the product. A sensory panel gave slightly lower flavour scores to hamburgers containing the protein extract, although whether this was due to the ‘soapy’ taste reported by Dawson et al. is not clear. (Hudson, 1994)

-> Improving Emulsification and Gelation

“Since MDM is used in the manufacture of emulsion products, emulsifying capacity (EC) is an important property of the raw material (Froning, 1981; Field, 1988). EC has been defined as the amount of oil that can be emulsified by the material prior to the reversion or collapse of the emulsion (Swift et al., 1961; Ivey et al., 1970; Kato et al. , 1985). Factors affecting the emulsifying properties of a protein are: protein concentration, medium pH, oil temperature, mechanical force and rate of oil-addition during emulsification “(Galluzzo & Regenstein, 1978; Wang & Zayas, 1992; Zorba et al., 1993 as quoted by Abdullah and Al‐Najdawi, 2005.

Although the protein complex isolated from washed MDM could be of use in altering textural properties of poultry products, further possibilities of effecting such changes exist. For instance, Smith and Brekke found that limited acid proteolysis improved the emulsifying capacity of actomyosin isolated from fowl MDM, as well as improving the quality of heat-set gels. Kurth used a model system to demonstrate the crosslinking of myosin and casein by a Ca-dependent acyltransfer reaction catalysed by transglutaminase (EC; R-glutaminyl peptide amine gamma-glutamyl transferase). Application of the technique to actomyosin prepared from turkey MDM showed that actin did not polymerize, but that the disappearance of myosin monomer was accompanied by a concomitant increase in polymer content and that the gel strength of enzyme-treated protein was greater. The polymerization could occur at temperatures as low as 4°C, thus opening up possibilities for the manufacture of new products. (Hudson, 1994)

Emulsifying capacity

MDM Mean Values
(Abdullah and Al‐Najdawi, 2005)

“Mean EC values are presented in Table 1 and show significantly higher values for both kinds of deboned meat without skin (treatment 2: manual deboning of skinned carcasses; treatment 4: mechanical deboning of skinned carcasses.). The presence of skin in MDM is considered detrimental to EC, because of its collagen content, and this view is supported by the significantly lower EC value obtained for MDM prepared from whole carcases (treatment 3: mechanical deboning of whole carcasses), in comparison with that from skinned carcasses (treatment 4: mechanical deboning of skinned carcasses). Deboning of skinned carcasses by hand (Treatment 2: manual deboning of skinned carcasses) significantly increased the proportion of insoluble protein in the meat (Table 1), which can have an adverse effect on EC. However, this would be counterbalanced, to some extent, by the relatively low pH of the material that would increase protein solubility. Increased levels of insoluble protein could lead to protein enveloping the added oil droplets, thereby reducing the total amount of oil that is available to be emulsified (Swift, et al., 1961). The concentration of protein is also critical in relation to its own stability. When the concentration is sufficiently low, the protein structure unfolds to a degree that favours stability (Ivey et al., 1970).” (Abdullah and Al‐Najdawi, 2005)

MDM EC during Freezing
(Abdullah and Al‐Najdawi, 2005)

“It is clear from Table 2, that EC values increased significantly during frozen storage of manually deboned meat, but declined in the case of MDM obtained from skinned carcasses (Treatment 4: mechanical deboning of skinned carcasses). These changes occurred exclusively during months 1 and 2, with no significant effect subsequently for any treatment group. The initial decline in EC values for Treatment 4 may be attributable to the partial denaturation of protein. Accordingly, the corresponding increase in EC for manually-deboned meat is likely to reflect the absence of any mechanical damage to the structure of the meat. In this state, the protein would remain largely intact.” (Abdullah and Al‐Najdawi, 2005)

Poultry MDM: Water Holding Capacity

“Another important property of meat used for product manufacture is water-holding capacity (WHC). Like other meats, poultry contains approximately 70% water in the raw state, much of which is not tightly bound and is known as ‘free water’ (Baker & Bruce, 1989). The WHC of muscle foods has been used as an index of palatability, microbial quality and manufacturing potential (Dagbjartsson & Solberg, 1972). It is highly important in the formulation, processing, cooking and freezing of meat products, because it relates to weight loss and ultimate quality of the finished product (Field, 1988). Factors affecting WHC are pH value, presence of iron, copper, calcium and magnesium from bone, content of skin and collagen, and the processes of cooking and freezing.” (Abdullah and Al‐Najdawi, 2005)

The pH values “obtained from mechanically deboned material (mechanical deboning of whole carcasses and mechanical deboning of skinned carcasses) were significantly higher than the values for manually-deboned meat (manual deboning of whole carcasses and manual deboning of skinned carcasses). This may be explained by the unavoidable incorporation of bone marrow in the MDM, which therefore had a higher pH. Crushing of the bones also would have released mineral substances capable of contributing to the increase in pH (Zorba et al., 1993), as well as raising the protein content and concentration of free amino acids. At higher pH values, protein solubility would be increased, limiting any possible improvement in the functional properties of the meat.” (Abdullah and Al‐Najdawi, 2005)

(Abdullah and Al‐Najdawi, 2005)

“There were no significant differences between treatment groups in relation to WHC (Table 3). Thus, neither the presence of skin nor the method of deboning influenced WHC values. The absence of a skin effect is in agreement with Field (1988), and the collagen content of MDM may have been too low. However, while mechanical deboning could have affected WHC, because of the higher pH values obtained (Table 1), this was not the case (cf. Demos & Mandigo, 1995).” (Abdullah and Al‐Najdawi, 2005)

MDM Changes in WHC During Freeze storage
(Abdullah and Al‐Najdawi, 2005)

“Table 4 shows that frozen storage only affected the meat from skinned carcasses, whether manually- or mechanically-deboned. WHC values declined significantly over the 3-month period, possibly because of the lower fat content and therefore greater rate of protein denaturation.” (Abdullah and Al‐Najdawi, 2005)

Poultry MDM and Pigment Concentration

MDM and Pigment Concentration
(Abdullah and Al‐Najdawi, 2005)

“Table 5 shows the differences between the experimental treatments for pigment concentration, which would have included both haemoglobin and myoglobin. It is evident that the mean value was significantly higher for MDM without skin (Treatment 4: mechanical deboning of skinned carcasses) and lowest in meat from manually deboned, whole carcasses (Treatment 1: manual deboning of whole carcasses). Pigment concentrations in meat obtained by either method of deboning were clearly influenced by the presence of skin, and were lower when skin was present, possibly because of a dilution effect. However, differences in this respect between whole and skinned carcasses were less for those that had been deboned mechanically. The higher values obtained are consistent with a release of haemoglobin from bone marrow during mechanical deboning.” (Abdullah and Al‐Najdawi, 2005)

“Meat colour was not measured instrumentally in this study, but some variation in colour was apparent. It may have involved the conversion of myoglobin to oxymyoglobin in MDM and binding of ions from the metal surface of the deboner to the haem pigment (Froning, 1981; Demos & Mandigo, 1995). Possible pH effects in MDM, resulting from the release of bone marrow, could have led to changes in the structure of myofibrillar protein and may have increased the amount of myoglobin extracted. Also, pH is known to be capable of influencing the porphyrin ring-structure of meat pigments through its effect on iron.” (Abdullah and Al‐Najdawi, 2005)

“Changes in pigment concentration during frozen storage are shown in Table 6. Results indicate that pigment levels either remained static or diminished over time. For manually-deboned carcasses, there was a significant decline when skin and its associated fat were absent, but not when skin was present, suggesting a possible protective effect in limiting pigment oxidation (Field, 1988). No such effect was observed for mechanical deboning, where oxidation of pigment would be more likely, because of the release of potentially oxidising substances.” (Abdullah and Al‐Najdawi, 2005)

Poultry MDM: Sensory Evaluation

MDM's Sensory Evaluation
(Abdullah and Al‐Najdawi, 2005)

“Initially, there were no significant differences between treatments with respect to aroma, colour, texture or overall acceptability of the meat, as judged by the sensory panel. After storage for up to 12 weeks (Table 7), aroma values showed little or no change for hand-deboned meat, but MDM from whole carcasses (Treatment 3: mechanical deboning of whole carcasses) showed a significant reduction in score that was indicative of deterioration. This change could be attributed to the higher fat content of the meat and therefore greater susceptibility to oxidation.” (Abdullah and Al‐Najdawi, 2005)

MDM Sensory Panel Score
(Abdullah and Al‐Najdawi, 2005)

“In relation to meat colour, manually-deboned meat stored for 6 weeks was more acceptable than either kind of MDM, presumably because of the lower haemoglobin content of the former. After 12 weeks, only hand-deboned meat from skinned carcasses (Treatment 2: manual deboning of skinned carcasses) was significantly different and more acceptable to the panel, although the reason for this is unclear.” (Abdullah and Al‐Najdawi, 2005)

“Meat texture was less affected by carcass treatment during storage in the frozen state for 6 weeks, and no significant differences were observed. After 12 weeks, however, significantly lower scores were obtained for both kinds of MDM. Thus, freezing may have further damaged meat structure and the presence of trace amounts of bone (Al-Najdawi & Abdullah, 2002) could have contributed to the lower panel rating. Overall acceptance scores were clearly better for the manually-deboned meat, both at 6 and 12 weeks of frozen storage.” (Abdullah and Al‐Najdawi, 2005)

Conclusion by Abdullah and Al‐Najdawi

“This study has confirmed the role of skin content in deboned meat as a factor affecting EC, but has found no effect of deboning method or incorporating skin on WHC, despite differences between manually- and mechanically-deboned meat with respect to pH. On the other hand, the influence of skin on pigment concentration appears to be mainly a dilution effect. Although higher pigment levels in MDM could be attributed to the release of bone marrow during the deboning process, assessment by a sensory panel showed no differences initially between the experimental treatments in relation to aroma, colour, texture or overall acceptability of the meat. Only after frozen storage for up to 12 weeks, were differences apparent in both functional and sensory properties, and the study has highlighted the superior keeping-quality of manually-deboned poultry meat, according to a sensory assessment.” (Abdullah and Al‐Najdawi, 2005)


This is a work-in progress. As I expand the functional value of different MDM or related products, I will add it to this document. It is an adventure in discovery!


Abdullah, B. and Al‐Najdawi, R. (2005), Functional and sensory properties of chicken meat from spent‐hen carcasses deboned manually or mechanically in Jordan. International Journal of Food Science & Technology, 40: 537-543. doi:10.1111/j.1365-2621.2005.00969.

EFSA Panel on Biological Hazards (BIOHAZ). 2013. Scientific Opinion on the public health risks related to mechanically separated meat (MSM) derived from poultry and swine; European Food Safety Authority (EFSA), Parma, Italy; EFSA Journal 2013;11(3) : 3137.

Groves, K and Knight, A. An evidence-based review of the state of knowledge on methods for distinguishing mechanically separated meat (MSM) from desinewed meat (DSM). Food Standards Agency & DEFRA

Hudson, B. J. F. (Editor). 1994. New and Developing Sources of Food Proteins. Springer – Science + Business Media. (Poultry – the versatile food by JM Jones)

Viuda-Martos, M; Fernández-López, J.; Pérez-Álvarez, J. A., Hui, YH (Editor) Mechanical Deboning, January 2012, DOI: 10.1201/b11479-30, In book: Handbook of Meat and Meat Processing, Chapter: Mechanical Deboning, Publisher: CRC Press; Taylor & Francis Inc.