Biltong often develops mildew. A chemical way of treating this is with natamycin (primaricin).
“It is a polyene macrolide antibiotic produced by submerged aerobic fermentation of Streptomyces natalensis and related species.
Its antifungal mechanism is very interesting. “The polyenes bind to ergosterol in the fungal cell membrane and thus weakens it, causing leakage of K+ and Na+ ions, which may contribute to fungal cell death. Amphotericin B, nystatin, and natamycin are examples of polyene antimycotics. They are a subgroup of macrolides.” (Hamilton-Miller,1973)
“Fermentation is conducted for several days, and the antibiotic is isolated either by broth extraction or by extraction of the mycelium. It is used as a food additive to control the growth of yeasts and moulds on the surface of cheese and other non-sterile products, such as meat and sausages.”
Application to Biltong that Develops Mildew
Dilute 1g per 100L liquid. Liquid can be vinegar or Worcestershire Sauce. Tumble into meat as normal.
If there are already mold on the meat, dilute the vinegar with water and add a bit of natamycin. Use UV lights in drying room. (Carlo Robertson)
Antonia Mattia, A., Cerniglia, C., and Baines, J.. WHO Food Additive Series: 49. Safety Evaluation of Certain Food Additives and Contaminants. Natamycin (Primaricin). Available in PDF: safariviewservice-31jan2019at193a57.
Carlo Robertson – private communication
Hamilton-Miller (1973). “Chemistry and Biology of the Polyene Macrolide Antibiotics” (PDF). Bacteriological Reviews. American Society for Microbiology. 37 (2): 166–196. PMC 413810. PMID 4578757.
The University of Texas Medical Branch at Galveston. “Polyene Antifungal Drugs”. Retrieved 29 January 2010, NCBI Bookshelf (1996).