ABSTRACT
Natamycin is a compound used to delay or prevent spoilage of certain foods and beverages by yeast or mold growth. Natamycin (also called pimaricin) was first discovered in 1955 in a culture filtrate of Streptomyces natalensis isolated from a soil sample in the Natal Province of South Africa. The compound is a tetraene polyene macrolide with a molecular weight of 665.7 Daltons. Commercial natamycin preparations made by fermentation in glucose-based media by selected Streptomyces strains contain approximately 50% natamycin blended with lactose. Natamycin is active against nearly all yeasts and molds but has no effect on bacteria or viruses. Most molds are inhibited at concentrations of 0.5 to 6 µg/ml and most yeasts at concentrations of 1.0 to 5.0 µg/ml. The target of natamycin inhibition in fungi is ergosterol, the primary sterol in fungal cell membranes. Because natamycin is crystalline and hydrophobic, it does not readily penetrate foods but remains at the surface where mold spoilage generally occurs. Subjects addressed in the chapter include natamycin’s physical and chemical properties, antimicrobial activity, mode of action, food application, regulatory status, detection and analysis, and toxicology.
