31 Jan 2023
Eben van Tonder

Introduction

Nigeria presents one of the fastest growing meat markets in Africa. At the same time, processors operate under particularly demanding conditions because ambient temperatures are high, refrigeration may be interrupted, distribution chains are often extended, and microbial spoilage pressure is substantial. Consequently, preservative systems must be selected using established microbiological principles rather than cost alone. Every preservative should complement, rather than replace, good manufacturing practice, sanitation, rapid chilling, hygienic slaughter, temperature control and appropriate packaging.

No preservative can compensate for poor hygiene or temperature abuse. Preservation should therefore be regarded as one component of a hurdle technology approach in which several preservation factors act together to suppress microbial growth while maintaining eating quality and extending commercial shelf life.[1 to 6]

The objective of this review is to evaluate preservatives commonly used in meat processing together with several additional preservative systems that have become increasingly important during the past two decades. Particular emphasis is placed on products manufactured under Nigerian conditions.

Summary of Recommended Preservatives for Nigerian Meat Processing

Fresh Chilled Meat

Function	Recommended system	Primary target	Comments
Bacterial inhibition	Sodium lactate or potassium lactate	Gram positive and Gram negative spoilage bacteria	Excellent for vacuum packed fresh meat
Listeria control	Sodium diacetate combined with sodium or potassium lactate	Listeria monocytogenes	One of the best documented commercial systems
Surface mould and yeast	Potassium sorbate where permitted	Yeasts and moulds	Mainly surface applications
Oxidation control	Sodium erythorbate or sodium ascorbate	Lipid oxidation and colour stability	Does not replace good oxygen management
Natural antioxidant	Rosemary extract with mixed tocopherols	Lipid oxidation	Particularly useful in high fat products

Cooked Chilled Meat

Function	Recommended system	Primary target	Comments
Primary antimicrobial	Sodium lactate	Broad spectrum bacterial inhibition	Excellent evidence base
Enhanced antimicrobial	Sodium lactate with sodium diacetate	Listeria and spoilage organisms	Widely used commercially
Oxidation control	Sodium erythorbate	Fat oxidation and cured colour stability	Standard industry practice
Natural antioxidant	Rosemary extract	Oxidation	Particularly effective in cooked poultry and beef products

Frozen Meat

Frozen storage greatly reduces microbial growth but does not kill most spoilage organisms. Therefore preservatives contribute relatively little to microbiological safety during frozen storage. Instead, antioxidant systems become more important because lipid oxidation continues, albeit slowly, throughout frozen storage.

Recommended antioxidant systems include sodium erythorbate, sodium ascorbate, rosemary extract, mixed tocopherols and appropriate oxygen barrier packaging.

Best Antimicrobial Systems

For commercial meat processing under Nigerian conditions the strongest scientific support currently exists for the following combinations.

• Sodium lactate.
• Sodium lactate together with sodium diacetate.
• Potassium lactate together with sodium diacetate.
• Buffered vinegar systems.
• Cultured dextrose systems where clean label products are desired.

Best Antioxidant Systems

• Sodium erythorbate.
• Sodium ascorbate.
• Rosemary extract.
• Mixed tocopherols.
• Oxygen exclusion through vacuum packaging or modified atmosphere packaging.

These systems should always be selected according to product type, legislation and desired shelf life.[2 to 11]

Understanding Meat Preservation

Preservation Is Based Upon Multiple Hurdles

Modern meat preservation no longer relies upon a single preservative. Instead, shelf life is achieved through combining multiple preservation hurdles that individually exert relatively small inhibitory effects but collectively prevent microbial growth.

The principal preservation hurdles include.

• Hygienic slaughter.
• Rapid chilling.
• Low storage temperature.
• Salt concentration.
• Water activity.
• Acidity.
• Oxygen management.
• Vacuum or modified atmosphere packaging.
• Preservatives.
• Heat treatment where applicable.

This hurdle concept remains the foundation of modern meat preservation science.[3,4]

Classification of Preservatives

Preservatives used in meat processing generally perform one or more of four functions.

Antimicrobial Preservatives

These suppress or delay the growth of spoilage bacteria and pathogenic microorganisms.

Examples include.

• Sodium lactate.
• Potassium lactate.
• Sodium diacetate.
• Potassium acetate.
• Buffered vinegar systems.
• Potassium sorbate.
• Sodium benzoate.

Antioxidants

These slow oxidative rancidity and preserve colour.

Examples include.

• Sodium erythorbate.
• Sodium ascorbate.
• Ascorbic acid.
• Rosemary extract.
• Mixed tocopherols.

Acidulants

These lower pH and thereby inhibit microbial growth.

Examples include.

• Acetic acid.
• Lactic acid.
• Sodium diacetate.
• Buffered vinegar.

Sulphite Compounds

Sulphites possess antimicrobial and antioxidant activity. However, their use in meat products is highly restricted in many jurisdictions because they may mask spoilage, bleach pigments, destroy thiamine and cause adverse reactions in sulphite sensitive individuals. Their permitted use therefore depends entirely upon national legislation and Codex provisions for specific food categories.[1,5,7]

Sodium Sulphite and Sodium Metabisulphite

Chemical Properties

Sodium sulphite consists of sodium ions combined with sulphite ions.

Sodium metabisulphite consists of sodium ions combined with the metabisulphite ion. Upon dissolution, particularly under acidic conditions, both compounds generate sulphite species and sulphur dioxide that exert antimicrobial and antioxidant effects.

The chemistry of sulphite equilibrium is influenced by pH, temperature and food composition. Greater antimicrobial activity generally occurs under acidic conditions because molecular sulphur dioxide becomes the predominant antimicrobial species.[8]

Mechanism of Action

Sulphite compounds inhibit microorganisms through several mechanisms.

• Penetration of microbial cells by molecular sulphur dioxide.
• Interference with essential metabolic enzymes.
• Reduction of cellular energy production.
• Inhibition of oxidative reactions.
• Oxygen scavenging.

Their antimicrobial activity is greatest against yeasts and moulds, while effectiveness against bacteria varies considerably between species.[8,9]

Practical Applications

Historically sulphites have been used in numerous foods including dried fruits, wines and beverages.

Their application in meat products has become increasingly restricted because sulphites may.

• Bleach myoglobin pigments.
• Destroy vitamin B1.
• Mask microbiological spoilage.
• Produce allergic reactions in susceptible individuals.

Consequently, sulphites are generally not considered first choice preservatives for modern fresh or cooked meat products despite their antimicrobial effectiveness. Current industry practice instead favours lactate based systems together with diacetates and antioxidant technologies for most processed meats.[1,5,10]

Potassium Sorbate and Sodium Benzoate

Potassium Sorbate

Potassium sorbate is the potassium salt of sorbic acid and is one of the most widely used food preservatives worldwide. Its principal activity is directed against yeasts and moulds, although it also inhibits some bacteria under favourable conditions. Antimicrobial activity increases as pH decreases because the undissociated sorbic acid molecule is primarily responsible for microbial inhibition.[8,11]

Unlike many preservatives, potassium sorbate has little influence on flavour when used within recommended concentrations. It is therefore widely applied in processed foods requiring extended refrigerated shelf life.

Mechanism of Action

Potassium sorbate inhibits microbial growth through several mechanisms.

• Disruption of cytoplasmic membrane integrity.
• Interference with nutrient transport.
• Inhibition of respiratory enzymes.
• Inhibition of amino acid metabolism.
• Suppression of yeast and mould reproduction.

Because bacterial inhibition is less pronounced at neutral pH, potassium sorbate should not be regarded as a primary preservative for fresh meat. Instead, it performs best when used together with other preservation hurdles.[8,11]

Applications in Meat Products

Potassium sorbate is primarily useful for.

• Surface treatment of dried sausages.
• Surface treatment of smoked products.
• Surface treatment of sliced cooked meats.
• Control of mould growth during refrigerated storage.

Its value for fresh meat is generally limited because fresh meat has a relatively high pH, usually between 5.4 and 6.2, where sorbate activity decreases substantially.

Advantages

• Excellent inhibition of yeasts.
• Excellent inhibition of moulds.
• Minimal sensory effects.
• Good compatibility with many packaging systems.

Limitations

• Reduced activity at higher pH.
• Limited effectiveness against many spoilage bacteria.
• Not a replacement for refrigeration.

Sodium Benzoate

Chemical Properties

Sodium benzoate is the sodium salt of benzoic acid. Like sorbate, antimicrobial activity depends strongly upon pH because only undissociated benzoic acid effectively penetrates microbial cell membranes.

Maximum antimicrobial activity occurs below approximately pH 4.5.[8]

Mechanism of Action

Benzoic acid enters microbial cells in its undissociated form. Once inside the cell, where the pH is higher, it dissociates and acidifies the cytoplasm. This disrupts intracellular pH regulation, inhibits enzyme systems and reduces energy production.

The result is inhibition of microbial growth rather than immediate microbial destruction.[8]

Applications

Sodium benzoate is widely used in acidic foods including.

• Fruit beverages.
• Sauces.
• Pickles.
• Dressings.

Its usefulness in fresh meat is comparatively limited because meat is only mildly acidic.

Consequently, sodium benzoate is not regarded as one of the preferred preservatives for fresh or cooked meat products.

Advantages

• Highly effective in acidic foods.
• Broad approval internationally.
• Good inhibition of yeasts and moulds.

Limitations

• Poor activity at normal meat pH.
• Limited value for fresh meat.
• Usually inferior to lactate based systems for processed meats.

Sodium Acetate and Sodium Diacetate

Chemical Properties

Sodium acetate is the sodium salt of acetic acid.

Sodium diacetate is a crystalline molecular complex consisting of sodium acetate together with acetic acid. Because it continuously releases acetic acid during dissolution, it generally provides stronger antimicrobial activity than sodium acetate alone.[8,12]

Mechanism of Action

Acetate preservatives inhibit microorganisms primarily through weak acid preservation.

Undissociated acetic acid penetrates microbial membranes before dissociating within the cell. This lowers intracellular pH, disrupts enzyme activity, reduces ATP production and ultimately suppresses growth.

Their activity extends against many spoilage bacteria, including important Gram positive organisms.[8]

Comparison Between Sodium Acetate and Sodium Diacetate

Sodium diacetate consistently demonstrates greater antimicrobial activity because it provides a greater reservoir of free acetic acid.

Numerous commercial studies have demonstrated improved inhibition of Listeria monocytogenes when sodium diacetate is combined with sodium or potassium lactate in ready to eat meat products.[13,14]

Consequently, sodium diacetate has become one of the most widely used secondary preservatives in cooked meat manufacture.

Applications

Sodium acetate is suitable for.

• Fresh sausages.
• Marinated meat.
• Some cooked products.

Sodium diacetate is particularly suitable for.

• Cooked ham.
• Frankfurters.
• Bologna.
• Vienna sausages.
• Sliced cooked meats.
• Ready to eat poultry products.

Advantages

• Excellent compatibility with lactates.
• Good inhibition of Listeria monocytogenes.
• Broad activity against spoilage bacteria.
• Minimal effect on colour.

Limitations

• Excessive concentrations may contribute acidic flavour.
• Activity remains dependent upon overall product formulation.

Sodium Lactate

Scientific Importance

Among all commercially available preservatives used in processed meat, sodium lactate possesses one of the strongest scientific evidence bases.

Over the past three decades numerous peer reviewed studies have demonstrated its effectiveness against spoilage organisms and foodborne pathogens, particularly in refrigerated cooked meat products.[13 to 16]

Consequently, sodium lactate has become one of the most important preservatives used by modern meat processors.

Mechanism of Action

Sodium lactate suppresses microbial growth through several complementary mechanisms.

• Reduction of water activity.
• Disruption of osmotic balance.
• Inhibition of microbial metabolism.
• Reduction of intracellular pH.
• Extension of bacterial lag phase.

Unlike many weak acid preservatives, sodium lactate remains effective over the normal pH range encountered in meat products.

Additional Technological Benefits

Besides microbial inhibition, sodium lactate offers several technological advantages.

• Improved water retention.
• Improved cooking yield.
• Improved juiciness.
• Reduced purge during storage.
• Enhanced flavour stability.
• Lower warmed over flavour development.

Because of these additional benefits, sodium lactate often contributes simultaneously to shelf life and eating quality.

Typical Applications

Sodium lactate is widely used in.

• Cooked ham.
• Frankfurters.
• Bologna.
• Mortadella.
• Roast beef.
• Cooked poultry.
• Ready to eat sliced meats.
• Vacuum packaged cooked products.

For chilled processed meat manufactured under Nigerian conditions, sodium lactate should generally be regarded as the benchmark preservative against which alternative antimicrobial systems are compared.[13 to 16]

Potassium Lactate

Scientific Background

Potassium lactate is the potassium salt of lactic acid and functions similarly to sodium lactate. It has become increasingly important because it provides equivalent antimicrobial activity while reducing the sodium content of processed meat products. This is particularly valuable where sodium reduction is a nutritional objective.

Like sodium lactate, potassium lactate has extensive scientific support for extending the shelf life of refrigerated meat products and inhibiting important foodborne pathogens.[13 to 16]

Mechanism of Action

Potassium lactate inhibits microorganisms through the same fundamental mechanisms as sodium lactate.

• Reduction of water activity.
• Interference with osmotic balance.
• Intracellular acidification.
• Disruption of microbial metabolism.
• Extension of bacterial lag phase.

Its antimicrobial spectrum includes many Gram positive and Gram negative spoilage bacteria, although activity depends upon the complete product formulation and storage temperature.

Applications

Potassium lactate is particularly suitable for.

• Reduced sodium meat products.
• Cooked sausages.
• Cooked poultry.
• Ready to eat sliced meats.
• Vacuum packaged products.
• Modified atmosphere packaged products.

Commercially, potassium lactate is frequently combined with sodium diacetate because the two preservatives provide complementary antimicrobial effects.

Buffered Vinegar Systems

Scientific Background

Buffered vinegar systems have become increasingly important within the meat industry because they satisfy consumer demand for recognisable ingredients while providing effective antimicrobial activity.

Commercial buffered vinegar ingredients typically contain acetate compounds produced through controlled fermentation followed by buffering to reduce acidity and improve flavour.

These ingredients are widely used in clean label meat products in Europe and North America.

Mechanism of Action

Buffered vinegar systems function primarily through undissociated acetic acid.

Following diffusion into microbial cells they reduce intracellular pH, inhibit enzyme activity and interfere with cellular metabolism.

Unlike unbuffered vinegar, buffered systems produce substantially less flavour impact while maintaining antimicrobial effectiveness.

Applications

Buffered vinegar systems are particularly suitable for.

• Cooked ham.
• Roast beef.
• Ready to eat poultry.
• Fresh sausages.
• Marinated meats.
• Vacuum packed sliced meats.

Several commercial studies have demonstrated inhibition of Listeria monocytogenes comparable with conventional acetate based preservative systems.[17]

Cultured Dextrose and Cultured Sugar Systems

Scientific Background

Cultured dextrose and cultured sugar ingredients are produced by fermenting carbohydrates with selected microorganisms that generate naturally occurring antimicrobial metabolites.

These fermentation products may contain mixtures of organic acids, peptides and other antimicrobial compounds.

Although their composition varies between manufacturers, they are increasingly used where processors wish to avoid chemically sounding ingredient declarations.

Mechanism of Action

Their preservation effects arise from several antimicrobial compounds produced during fermentation.

These include.

• Organic acids.
• Antimicrobial peptides.
• Fermentation metabolites.

Together they suppress spoilage organisms and extend refrigerated shelf life.

Applications

Cultured dextrose systems are suitable for.

• Cooked sliced meats.
• Ham.
• Poultry products.
• Fresh sausages.
• Ready to eat products.

Their effectiveness depends upon the formulation and should always be validated through commercial shelf life studies.

Potassium Acetate

Scientific Background

Potassium acetate provides antimicrobial activity comparable with sodium acetate while reducing sodium intake.

It has become increasingly common in cooked meat formulations, particularly where sodium reduction programmes are implemented.

Mechanism of Action

The antimicrobial mechanism is identical to acetate preservation generally.

• Intracellular acidification.
• Enzyme inhibition.
• Reduced microbial metabolism.
• Inhibition of bacterial multiplication.

Applications

Potassium acetate is frequently combined with potassium lactate to provide broad spectrum antimicrobial activity in cooked meat products.

Commercial combinations of potassium lactate and potassium acetate have demonstrated significant inhibition of Listeria monocytogenes and refrigerated spoilage bacteria.[13,14]

Sodium Erythorbate

Scientific Background

Sodium erythorbate is not primarily an antimicrobial preservative. Instead, it functions as one of the meat industry’s most effective antioxidants.

It is the stereoisomer of sodium ascorbate and performs essentially the same technological functions within cured meat products.

Mechanism of Action

Sodium erythorbate.

• Scavenges oxygen radicals.
• Delays lipid oxidation.
• Protects cured pigment.
• Accelerates nitric oxide formation from nitrite.
• Improves cured colour development.

By reducing oxidation it also delays the development of rancid flavours during refrigerated and frozen storage.

Applications

Sodium erythorbate is widely used in.

• Bacon.
• Ham.
• Frankfurters.
• Vienna sausages.
• Bologna.
• Corned beef.
• Cured poultry.

It should not be regarded as a replacement for antimicrobial preservatives because its primary function is oxidative stability rather than microbial inhibition.

Sodium Ascorbate and Ascorbic Acid

Scientific Background

Sodium ascorbate and ascorbic acid are among the oldest antioxidants used in meat processing.

Both compounds reduce oxidation while accelerating cured colour development.

Technological Functions

They.

• Reduce lipid oxidation.
• Stabilise colour.
• Improve flavour stability.
• Accelerate curing reactions.
• Reduce residual nitrite during curing.

Because they improve oxidative stability without materially affecting flavour, they remain standard ingredients in cured meat manufacture throughout the world.[18]

Rosemary Extract

Scientific Background

Rosemary extract has become one of the most extensively studied natural antioxidants used in meat processing.

Its activity arises principally from phenolic diterpenes including carnosic acid and carnosol.

Numerous peer reviewed studies have demonstrated significant reductions in lipid oxidation in fresh, cooked and frozen meat products.[19]

Mechanism of Action

Rosemary extract.

• Scavenges free radicals.
• Chelates pro oxidant metals.
• Interrupts oxidation chain reactions.
• Protects unsaturated lipids.
• Preserves flavour during storage.

Unlike antimicrobial preservatives, rosemary extract contributes primarily to oxidative stability rather than microbial inhibition.

Applications

Rosemary extract is particularly effective in.

• Beef burgers.
• Lamb products.
• Poultry.
• Pork sausages.
• Frozen meat.
• High fat emulsified products.

It performs especially well when combined with oxygen barrier packaging and appropriate refrigerated storage.

Mixed Tocopherols

Scientific Background

Mixed tocopherols comprise naturally occurring forms of vitamin E that function as lipid soluble antioxidants.

They are widely used to delay oxidative rancidity in high fat meat products.

Applications

Mixed tocopherols are particularly useful for.

• Frozen meat.
• Frozen poultry.
• High fat sausages.
• Dry sausages.
• Rendered fats.
• Beef tallow.
• Poultry fat.

Although antimicrobial activity is negligible, their antioxidant activity substantially extends flavour stability during frozen storage.[19,20]

Comparison of Preservative Systems

Antimicrobial Effectiveness

The antimicrobial spectrum of commonly used meat preservatives differs considerably. Consequently, preservative selection should always be based upon the principal spoilage organisms expected in a particular product rather than assuming that one preservative is universally superior.

Preservative	Gram Positive Bacteria	Gram Negative Bacteria	Yeasts	Moulds	Antioxidant Activity
Sodium lactate	Excellent	Good	Limited	Limited	None
Potassium lactate	Excellent	Good	Limited	Limited	None
Sodium diacetate	Excellent	Moderate	Moderate	Moderate	None
Sodium acetate	Moderate	Moderate	Limited	Limited	None
Potassium acetate	Moderate	Moderate	Limited	Limited	None
Potassium sorbate	Limited	Limited	Excellent	Excellent	None
Sodium benzoate	Limited	Limited	Good at low pH	Good at low pH	None
Sodium erythorbate	None	None	None	None	Excellent
Sodium ascorbate	None	None	None	None	Excellent
Rosemary extract	None	None	None	None	Excellent
Mixed tocopherols	None	None	None	None	Excellent

Adapted from Leistner, ICMSF, Lawrie, Toldrá and Feiner.[2 to 6,18 to 20]

Selection According to Product Type

Fresh Beef

Fresh beef presents unique preservation challenges because the product remains microbiologically active, possesses relatively high water activity, and normally exhibits a pH between approximately 5.4 and 5.8.

The most appropriate preservation strategy combines.

• Hygienic slaughter.
• Rapid chilling.
• Continuous refrigeration.
• Vacuum packaging or suitable modified atmosphere packaging.
• Sodium lactate where formulation permits.
• Appropriate antioxidant systems if fat oxidation is a concern.

Potassium sorbate and sodium benzoate generally provide limited benefit because fresh meat pH reduces their antimicrobial effectiveness.

Fresh Poultry

Fresh poultry generally carries higher initial microbial loads than red meat because contamination during slaughter is more difficult to control.

Consequently, preservation should focus upon.

• Excellent sanitation.
• Rapid chilling.
• Strict temperature management.
• Lactate based preservation.
• Buffered vinegar systems where appropriate.

Surface mould inhibitors provide relatively little benefit because bacterial spoilage normally limits shelf life before fungal growth becomes significant.

Fresh Sausages

Fresh sausages contain minced meat, increased surface area and frequently non meat ingredients that support microbial growth.

Recommended preservative systems include.

• Sodium lactate.
• Potassium lactate.
• Buffered vinegar.
• Appropriate oxygen management.
• Strict refrigeration.

Shelf life should always be validated microbiologically under local storage conditions.

Cooked Meat Products

Cooked products require a different preservation strategy because vegetative pathogens have been substantially reduced by heat treatment, while post cooking contamination becomes the principal hazard.

One of the greatest microbiological concerns is Listeria monocytogenes, which may contaminate products during slicing and packaging.

The strongest scientific evidence supports combinations of.

• Sodium lactate.
• Sodium diacetate.
• Potassium lactate.
• Potassium acetate.
• Vacuum packaging.
• Continuous refrigeration below 4 degrees Celsius.

Numerous published studies have demonstrated substantial inhibition of Listeria monocytogenes using lactate and diacetate combinations in ready to eat meat products.[13 to 16]

Vacuum Packaged Products

Vacuum packaging removes oxygen and therefore suppresses aerobic spoilage organisms.

However, facultative anaerobic bacteria and psychrotrophic organisms remain capable of growth.

Consequently, vacuum packaging should be combined with antimicrobial preservatives rather than being regarded as sufficient on its own.

Recommended systems include.

• Sodium lactate.
• Potassium lactate.
• Sodium diacetate.
• Buffered vinegar.
• Refrigerated storage.

Antioxidants remain important because oxidative reactions continue, although more slowly than under aerobic conditions.

Modified Atmosphere Packaging

Modified atmosphere packaging represents one of the most effective preservation technologies available for chilled meat.

Carbon dioxide possesses bacteriostatic activity against many spoilage organisms, while oxygen influences colour stability and nitrogen functions primarily as an inert filler gas.

Preservatives should therefore be selected to complement rather than replace modified atmosphere packaging.

Examples include.

• Sodium lactate with high carbon dioxide atmospheres for cooked products.
• Rosemary extract for fresh burgers.
• Sodium erythorbate for cured cooked products.
• Buffered vinegar systems for sliced meats.

The combined effect of refrigeration, carbon dioxide and preservatives represents a classic hurdle technology approach.[3,4]

Frozen Meat Products

Freezing prevents microbial multiplication but does not eliminate microorganisms.

Most spoilage bacteria remain viable after thawing.

Consequently, microbiological preservatives contribute relatively little additional benefit during frozen storage.

Instead, preservation should focus upon reducing oxidative deterioration.

Recommended antioxidant systems include.

• Sodium erythorbate.
• Sodium ascorbate.
• Rosemary extract.
• Mixed tocopherols.
• Oxygen barrier packaging.
• Vacuum packaging.

For fatty beef, poultry and pork products, antioxidant selection has a much greater influence on storage stability than antimicrobial preservatives.

Preservatives That Should Not Normally Be Selected as First Choice

Certain preservatives are technically effective but are generally not preferred for modern meat processing because superior alternatives now exist.

Sodium Sulphite and Sodium Metabisulphite

These compounds possess antimicrobial activity but have significant disadvantages.

• Potential destruction of thiamine.
• Possible allergic reactions in sulphite sensitive individuals.
• Possible bleaching of meat pigments.
• Highly restricted use in many meat categories.
• Risk of masking spoilage if misused.

Consequently, sulphites should only be used where specifically permitted by applicable legislation.

Sodium Benzoate

Although sodium benzoate is an excellent preservative in acidic foods, fresh meat products normally possess insufficient acidity for optimum antimicrobial performance.

It therefore has relatively limited usefulness in most meat products.

Preservative Systems Recommended for Nigeria

Considering climate, distribution, refrigeration challenges and current scientific evidence, the following systems represent the strongest choices for commercial meat processors.

Product	Recommended antimicrobial system	Recommended antioxidant system
Fresh beef	Sodium lactate	Rosemary extract if required
Fresh poultry	Sodium lactate with buffered vinegar where appropriate	Rosemary extract
Fresh sausage	Sodium lactate	Rosemary extract
Cooked ham	Sodium lactate with sodium diacetate	Sodium erythorbate
Frankfurters	Sodium lactate with sodium diacetate	Sodium erythorbate
Bologna	Sodium lactate with sodium diacetate	Sodium erythorbate
Cooked poultry	Potassium lactate with sodium diacetate	Rosemary extract
Frozen burgers	Not normally required	Rosemary extract with mixed tocopherols
Frozen sausages	Not normally required	Sodium erythorbate or rosemary extract

These recommendations are consistent with current meat science literature and recognised hurdle technology principles rather than reliance upon any single preservative.[2 to 6,13 to 20]

Regulatory Considerations

Codex Alimentarius

The Codex Alimentarius Commission establishes internationally recognised food standards developed jointly by the Food and Agriculture Organization of the United Nations and the World Health Organization. These standards provide the basis for many national food regulations, including those governing food additives.[1]

Not every preservative is permitted in every meat product. Approval depends upon.

• The specific food category.
• Maximum permitted concentrations.
• Technological justification.
• Consumer safety.
• National legislation.

Processors should therefore always verify that the intended preservative is authorised for the specific product category being manufactured.

Nigerian Regulatory Considerations

In Nigeria, food additives are regulated by the National Agency for Food and Drug Administration and Control. Products manufactured for export must also comply with the legislation of the importing country.

Consequently, preservative selection should satisfy.

• Nigerian legislation.
• Codex requirements where applicable.
• Import country legislation.
• Customer specifications.
• Retailer requirements.

Preservatives Do Not Replace Good Manufacturing Practice

No preservative should ever be regarded as an alternative to proper process control.

The principal determinants of meat shelf life remain.

• Healthy livestock.
• Hygienic slaughter.
• Good manufacturing practice.
• Effective sanitation.
• Rapid carcass chilling.
• Low processing temperatures.
• Prevention of cross contamination.
• Effective packaging.
• Continuous refrigeration.

When these factors are poorly controlled, preservatives cannot reliably prevent spoilage or ensure microbiological safety.

Modern preservation therefore relies upon integrating preservatives into a complete food safety system rather than treating them as the primary control measure.[2 to 6]

Practical Recommendations for Nigerian Meat Processors

Fresh Beef

Priority should be given to.

• Hygienic slaughter.
• Rapid chilling.
• Vacuum packaging where practical.
• Sodium lactate when formulation permits.
• Rosemary extract only where oxidative stability is required.

Fresh Poultry

Priority should be given to.

• Excellent sanitation.
• Immediate chilling.
• Strict cold chain management.
• Sodium lactate.
• Buffered vinegar systems where appropriate.

Cooked Ham

Recommended systems include.

• Sodium lactate.
• Sodium diacetate.
• Sodium erythorbate.
• Vacuum packaging.
• Storage below 4 degrees Celsius.

Frankfurters and Vienna Sausages

Recommended systems include.

• Sodium lactate.
• Sodium diacetate.
• Sodium erythorbate.
• Vacuum packaging or modified atmosphere packaging.
• Continuous refrigeration.

Fresh Sausages

Recommended systems include.

• Sodium lactate.
• Buffered vinegar where appropriate.
• Good temperature control.
• Oxygen management.

Frozen Meat Products

The emphasis should shift from microbial inhibition towards prevention of oxidative deterioration.

Recommended systems include.

• Sodium erythorbate.
• Sodium ascorbate.
• Rosemary extract.
• Mixed tocopherols.
• High quality oxygen barrier packaging.
• Vacuum packaging where appropriate.

Overall Assessment of Preservatives

Based upon current meat science literature, commercial practice and regulatory acceptance, the principal preservative systems may be summarised as follows.

Preservative	Principal Function	Best Application
Sodium lactate	Broad spectrum antimicrobial	Fresh and cooked chilled meat
Potassium lactate	Broad spectrum antimicrobial with reduced sodium	Fresh and cooked chilled meat
Sodium diacetate	Secondary antimicrobial. Particularly effective with lactates	Cooked ready to eat products
Potassium acetate	Secondary antimicrobial	Reduced sodium cooked products
Buffered vinegar	Antimicrobial. Clean label	Fresh and cooked products
Cultured dextrose	Antimicrobial. Clean label	Cooked products
Potassium sorbate	Yeast and mould inhibition	Surface applications
Sodium benzoate	Antimicrobial in acidic foods	Limited use in meat
Sodium erythorbate	Antioxidant	Cured meat products
Sodium ascorbate	Antioxidant	Cured meat products
Rosemary extract	Natural antioxidant	Fresh, cooked and frozen meat
Mixed tocopherols	Natural antioxidant	Frozen and high fat products

Conclusion

Successful meat preservation depends upon the interaction of hygienic production, temperature control, packaging technology and scientifically selected preservative systems. No individual preservative is capable of ensuring product safety in isolation.

Among antimicrobial preservatives currently available for meat processing, sodium lactate and potassium lactate possess the strongest scientific support because they consistently inhibit spoilage bacteria while improving water retention and eating quality. Their effectiveness is further enhanced when combined with sodium diacetate or potassium acetate, particularly in cooked ready to eat products where inhibition of Listeria monocytogenes is a major objective.

For products requiring oxidative stability, sodium erythorbate and sodium ascorbate remain the industry standards for cured meats. Rosemary extract and mixed tocopherols provide highly effective natural antioxidant systems for fresh, cooked and frozen products.

Buffered vinegar and cultured dextrose technologies have expanded the range of available preservative systems for processors seeking clean label formulations while maintaining microbiological safety.

Sulphite based preservatives possess recognised antimicrobial activity but should not normally be considered first choice for modern meat processing because of legislative restrictions, potential adverse reactions in sensitive individuals, destruction of thiamine and the availability of superior preservative technologies.

For Nigerian meat processors operating under high ambient temperatures and challenging distribution conditions, the most effective strategy is the application of hurdle technology. Hygienic slaughter, rapid chilling, continuous refrigeration, suitable packaging and scientifically selected preservative systems work together to extend shelf life, improve product quality and enhance food safety. This integrated approach remains the foundation of modern meat preservation.

References

1. Codex Alimentarius Commission. General Standard for Food Additives. CXS 192. Food and Agriculture Organization of the United Nations and World Health Organization.
2. Leistner, L. 2000. Basic aspects of food preservation by hurdle technology. International Journal of Food Microbiology. 55. 181 to 186.
3. Leistner, L., and Gould, G. W. 2002. Hurdle Technologies. Combination Treatments for Food Stability, Safety and Quality. Kluwer Academic Publishers.
4. International Commission on Microbiological Specifications for Foods. 2005. Microorganisms in Foods 6. Microbial Ecology of Food Commodities. Springer.
5. Lawrie, R. A., and Ledward, D. A. 2006. Lawrie’s Meat Science. Seventh Edition. Woodhead Publishing.
6. Feiner, G. 2006. Meat Products Handbook. Practical Science and Technology. Woodhead Publishing.
7. World Health Organization. 2017. Evaluation of Certain Food Additives. WHO Technical Report Series 1007.
8. Adams, M. R., and Moss, M. O. 2008. Food Microbiology. Third Edition. Royal Society of Chemistry.
9. Davidson, P. M., Sofos, J. N., and Branen, A. L. 2005. Antimicrobials in Food. Third Edition. CRC Press.
10. Food and Drug Administration. Food Additive Status List.
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