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What is Natamycin?

“The customer is always right,” is a time-honoured adage in marketing. It holds true even if the customer is wrong. If the customer does not want “artificial” preservatives” in food, industry will comply, whether that move is supported by science or not.

“The customer is always right,” is a time-honoured adage in marketing. It holds true even if the customer is wrong. If the customer does not want “artificial” preservatives” in food, industry will comply, whether that move is supported by science or not. Of course no company wants to poison its customers, so eliminating preservatives is a risky business. What’s the answer? Look for a “natural” preservative. That will satisfy the consumer who has a disdain for anything artificial, and at the same time will reduce the worry for the producer about marketing an unsafe product.

Kraft, for example, has announced that, at least in the U.S., it will be replacing artificial preservatives with natural ones in its cheese products. This boils down to not much more than a question of semantics. Sorbic acid and its salts, the “artificial” preservatives that have been used, are to be replaced by natamycin, an antifungal compound produced by soil bacteria. Although many cheeses are actually mould ripened, with blue cheese being the classic example, cheese is also prone to infection by a variety of rogue moulds that can cause spoilage. Sorbic acid and its salts can prevent the growth of moulds, yeast and fungi, even when used at concentrations of less than 0.1%. It was back in 1859 that Professor August Wilhelm Hofmann first isolated sorbic acid by distilling the oil obtained from the berries of the rowan tree. This is the same Professor Hofmann who was enticed to England by Prince Albert to head up the newly created Royal College of Chemistry and who essentially founded the synthetic dye industry.

So, doesn’t the fact that sorbic acid can be isolated from berries make it a “natural” substance? Yes. And I suppose there would be no clamoring to remove it from food if this is how it were produced. But distilling sorbic acid from rowan berries is not an economical process and would not do for the estimated 30,000 tons needed every year by the food industry. But sorbic acid can also be readily produced by a number of synthetic methods, including the reaction of crotonaldehyde with ketene, both of which can be made from compounds isolated from petroleum. This synthesis is economically viable and is the way that sorbic acid is produced. Any chemical is defined by its molecular structure which does not depend on the route by which it was produced. The sorbic acid produced by the rowan berry is identical to the sorbic acid produced by chemical synthesis, but because the latter was not extracted from a natural source, it is termed “artificial,” and therefore in the eyes of some people, suspect. The fact is that sorbic acid, irrelevant of the source, is a food additive that has passed all the regulatory hurdles just like its replacement, natamycin.

Natamycin is an antifungal agent produced by a soil bacterium that was first found in South Africa’s Natal province, hence the name. Since bacteria occur in nature, any of the chemicals they crank out can be classified as “natural.” But curiously a substance that occurs in nature, like sorbic acid, is termed an artificial preservative when it is synthesized in the lab. Natamycin may be natural, but it would not be so appealing to people if they knew they were eating the waste product of dirt bacteria. Not that there is anything wrong with that.