Everything you always wanted to know about the biopreservative natamycin

The discovery of natamycin 65 years ago

Natamycin occurs naturally in soil, as a result of natural biological bacterial fermentation. 65 years ago, in 1954, natamycin was discovered by DSM scientists in a soil sample from the state of Natal, South Africa, hence its name. The scientists observed that this antifungal agent blocks the growth of yeasts and molds by a unique mechanism that prevents nutrient uptake.

Natamycin was first isolated from a culture of Streptomyces natalensis in the DSM research laboratories. After thorough research and application work by DSM, it was launched in 1967 as a biopreservative for several food applications and is marketed under the well-known brand Delvo®Cid.

The natural working mechanism of natamycin against yeast and molds

Natamycin binds to ergosterol, a building block in the cell walls of yeasts and molds. Ergosterol enables the transport of food across the membrane. When natamycin binds to ergosterol, the transport of nutrients gets blocked and the cell starves to death. Bacteria do not contain ergosterol and are therefore not affected. Natamycin is effective in extremely small quantities (parts per million).

Natamycin safely prevents harmful molds without interfering with bacterial fermentation

Molds can be divided into harmful or useful and friendly molds. Useful, friendly molds are needed to produce the great tasting blue cheeses such as brie and camembert. The same applies to yeasts. Useful yeasts are used in the production processes of beer, wine and bread.

However, on most foods the growth of yeasts and molds is not appreciated. Contamination of food products with harmful yeasts and molds may lead to food spoilage.

Some mold strains - that can also grow on cheese - can produce toxins when under stress. These are called mycotoxins and are dangerous for human health. Natamycin inhibits molds, including these toxin producing strains.

Because natamycin is not active against bacteria it will not interfere with bacterial fermentation processes such as those for cheese, fermented milk products, or sausages.

Natamycin is widely used to prevent food spoilage

Natamycin is commonly used in food products such as cheese and sausages to prevent the growth of molds and yeasts, and to naturally extend shelf life and reduce food waste. In some countries, depending on regulatory approvals, natamycin is also used in other products such as bread, cakes, beverages and yoghurt.

Natamycin is a natural preservative without safety risk

Natamycin is a natural preservative that has been tested extensively; the test levels in toxicity studies are well determined. In the quantities applied to food products, there is no safety risk. This has been evaluated and approved by main Expert Committees on Food Additives by JECFA and confirmed by EFSA and FDA.

Natamycin can be labeled as a natural mold inhibitor

How natamycin has to be labeled depends on legislation per area. In the EU it can be labelled as E235, or natamycin. In the US it will be labeled as natamycin. Often, natamycin is indicated on the packaging of food products as a natural mold inhibitor, and is suitable for the claim ‘free from artificial ingredients’.