Natamycin has a strong inhibitory effect on molds, yeasts and fungi, but has no inhibitory effect on bacteria, viruses and other microorganisms. Natamycin has a certain heat treatment resistance, relatively stable in dry state, and can withstand short-term high temperature (100 ℃); However, it is not suitable to contact with sunlight because of its ring chemical structure and sensitivity to ultraviolet rays. The anchor stability of natamycin activity is affected by pH value, temperature, light intensity, oxidants and heavy metals, so the product should avoid contact with oxides and hydrogen sulfide compounds. In June 1982, the FDA officially approved natamycin as a food preservative and classified it as gras products. Natamycin is a highly effective inhibitor of mold, yeast and fungi. It is used to inhibit mold, yeast and fungi in food. It is very safe and reliable to human body, and does not affect the flavor of products. It is widely used in cheese, meat products, cakes, fruit juice and other foods all over the world. The product is refined from streptomycin by deep fermentation and multi-step extraction process. The preparation is made by mixing 50% natamycin and 50% lactose.