Uses
Medical
Natamycin is used to treat fungal infections, including ''Candida (genus), Candida'', ''Aspergillus'', ''Cephalosporium'', ''Fusarium'', and ''Penicillium''. It is applied topically as a cream, in eye drops, or (for oral infections) in a throat lozenge, lozenge. Natamycin shows negligible absorption into the body when administered in these ways. When taken orally, little or none is absorbed from the gastrointestinal tract, making it inappropriate for systemic infections. Natamycin lozenges are also prescribed to treat yeast infections and oral thrush.Food
Natamycin has been used for decades in the food industry as a hurdle to fungal outgrowth in dairy products and other foods. Potential advantages for the usage of natamycin might include the replacement of traditional chemical preservatives, a neutral flavor impact, and less dependence on pH for efficacy, as is common with chemical preservatives. It can be applied in a variety of ways: as an aqueous suspension (such as mixed into a brine) sprayed on the product or into which the product is dipped, or in powdered form (along with an anticaking agent such as cellulose) sprinkled on or mixed into the product. While not currently approved for use on meats in the United States, some countries allow natamycin to be applied to the surface of dry and fermented sausages to prevent mold growth on the casing. Also, natamycin is approved for various dairy applications in the United States. More specifically, natamycin is commonly used in products such as cream cheeses, cottage cheese, sour cream, yogurt, shredded cheeses, cheese slices, and packaged salad mixes. One of the reasons for food producers to use natamycin is to replace the artificial preservative sorbic acid. As a food additive, it has E number E235. Throughout the European Union, it is approved only as a surface preservative for certain cheese and dried sausage products. It must not be detectable 5 mm below the rind. While natamycin is approved in different applications at different levels in the world, it is approved in over 150 countries worldwide. The European Food Safety Authority (EFSA) panel took over the responsibilities of providing scientific food safety advice to the EU from the Scientific Committee on Food in 2002. In 2009, the EFSA considered the proposed use levels of natamycin are safe if it is used for the surface treatment for these cheese and sausage types.Scientific Opinion on the use of natamycin (E 235) as a food additiveSafety
Natamycin does not have acute toxicity. In animal studies, the lowest found was 2.5-4.5 g/kg. In rats, the LD50 is ≥2300 mg/kg, and doses of 500 mg/kg/day over 2 years caused no detectable differences in survival rate, growth, or incidence of tumors. The metabolites of natamycin also lack toxicity. The breakdown products of natamycin under various storage conditions may have a lower LD50 than natamycin, but in all cases, the numbers are quite high. In humans, a dose of 500 mg/kg/day repeated over multiple days caused nausea, vomiting, and diarrhea.Mattia, A. et al. Safety evaluation of certain food additives and contaminants: natamicin (pimaricin). WHO Food Additives Series #48.Mechanism of action
Natamycin inhibits the growth of fungi by specifically binding to ergosterol present in fungal cell membranes. Natamycin inhibits amino acid and glucose transport proteins leading to a loss of nutrient transport across the plasma membrane. While this binding is reversible, ergosterol binding acts as a universal mechanism of fungal inhibition, allowing natamycin to act on diverse fungal pathogens from ''Saccharomyces'' yeast to ''Aspergillus'' moulds. Natamycin is unique amongst related antifungals specifically because it does not directly cause membrane permeabilization. Structurally-related antibiotics with similar binding properties are thought to produce hydrophilic channels that allow leakage of potassium and sodium ions from the cell. Natamycin has very low solubility in water; however, natamycin is effective at very low levels. Its minimum inhibitory concentration is less than 10 Parts per million, ppm for most molds.Biochemistry
Natamycin is produced as a secondary metabolite by some ''Streptomyces'' species: ''Streptomyces natalensis, S. natalensis'', ''Streptomyces lydicus, S. lydicus'', ''Streptomyces chattanoogensis, S. chattanoogensis'' and ''Streptomyces gilvosporeus, S. gilvosporeus''. Structurally, its core is a macrolide containing a polyene segment, with carboxylic acid and mycosamine groups attached. As with other polyene antimycotics, the biosynthesis begins with a series of polyketide synthase modules, followed by additional enzymatic processes for oxidation and attachment of the substituents. Natamycin is produced on an industrial scale by fermentation of various ''Streptomyces'' strains, including ''S. chattanoogensis'' L10.History
Natamycin was first isolated in 1955 from fermentation broth of a ''Streptomyces natalensis'' cell culture."Pimaricin, a new antifungal antibiotic" in Antibiotics Annual in 1957. Natamycin VGP (http://www.natamycinvgp.com/the-origins-of-natamycin/#prettyPhoto) It was originally named ''pimaricin'' to honor Pietermaritzburg, where ''Streptomyces natalensis'' was acquired. Pimaricin was later renamed after the World Health Organization (WHO) mandated that antibiotics produced by ''Streptomyces'' end in –mycin. The name ''natamycin'' was chosen in reference to the ''natalensis'' species name.Society and culture
Natamycin appears on Whole Foods' "Unacceptable Ingredients for Food" list.Unacceptable Ingredients for Food (http://www.wholefoodsmarket.com/about-our-products/quality-standards/food-ingredient)References
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