Natamycin, also known as pimaricin, is a fungicide of the polyene macrolide group, commonly used as a biopreservative in the surface treatment of cheeses and sausages to inhibit yeasts and moulds. It also can be used in yogurt, baked goods, beverages and wines. The European food additive number for it is E235.
It is available in four types in the market, pure natamycin, 50% natamycin preparations with excipients of lactose, glucose or salt.
Natamycin is a natural antimycotic ingredient produced by controlled fermentation of Streptomyces natalensis (commonly found in soil) and other relevant species and then through the manufacturing process of extraction, crystallization and drying process.
Natamycin inhibits the growth of yeast and mold, also prevents the production of their toxins, but has no effect on bacteria as their membrane lacks sterols. Its mechanism of action is binding to sterols (principally ergosterol) in the fungal cell membrane instead of permeabilizing the membrane (1), which is the functional mechanism of chemical synthesized preservatives – sorbates and benzoates.
- Tasteless, odorless and will not affect food appearance, taste and colour
- A broad-spectrum antimycotic activity
- Effective at low doses (1 – 10 ppm)
- Active in a wide pH range (pH 3 – 9): making it suitable for acidic, neutral and alkaline foods
White to creamy-white crystalline powder.
Practically insoluble in water lipid and mineral oils; slightly soluble in methanol.
Natamycin can effectively inhibit the growth and reproduction of various molds and yeasts, but no inhibitory effect on bacteria. It is commonly used to kill yeast and mold on the surface of the natural fermentation products, such as yogurt, cheese, ham, and dry sausage and therefore extend the shelf life. It is used as an antifungal infection of eyes in pharmaceuticals.
How to use it?
Spray natamycin aqueous solution on the surface of the cheese to prevent cheese mildew and extend the shelf life. It is also workable by soaking cheese in the solution.
Soak the sausage with a concentration of 300mg/L natamycin aqueous solution to prevent casing stickiness and mildew.
It can prevent spoilage and extend the shelf life of juices of fruit & vegetable, and wine by adding 5-10mg/kg natamycin. It can also be used in un-yeast fermented baked goods.
Natamycin VS Sorbates and Benzoates
The low solubility of natamycin is an advantage for the surface treatment of food as it will stay on the surface of the food where most molds and yeasts may grow thus preventing their growth.
In contrast, the artificial preservatives, potassium sorbate and sodium benzoate are water-soluble and can be penetrated into food, thus making its concentration at the surface going down and therefore mold will grow.
A news in 2014 reported that Kraft was replacing sorbic acid by the natural mold inhibitor – natamycin in wrapped cheese slices (2). Now the label of the cheese Kraft Singles American Cheese Slices is marked as no artificial flavors or preservatives and you’ll see natamycin in the ingredients list. (3)
Yes, its safety when used as a food additive has been approved by the U.S. Food and Drug Administration (FDA), Canada Health, European Food Safety Authority (EFSA), Joint FAO/WHO Expert Committee on Food Additives (JECFA), as well as other authorities.
It is permitted for direct addition to food for human consumption and may be used as an antimycotic on cheese in amounts not more than 20 mg/kg. (4)
By the way, FDA had no question on DSM’s conclusion that natamycin is Generally Recognized as Safe (GRAS) when used as an antimycotic to prevent the growth of molds and yeasts in ready-to-drink tea beverages, fruit-flavored beverages & energy drinks, and sport and isotonic drinks at levels not more than 0.5 mg/kg (5) AND in yogurt at levels not to exceed 5 ppm. (6)
It is permitted to used in preventing mould growth on the surfaces of cheeses with the maximum levels (7):
- (naming the variety) cheese and cheddar cheese: 20ppm
- Grated or shredded (naming the variety) cheese and grated or shredded cheddar cheese:10ppm
Natamycin (E235) is listed in Commission Regulation (EU) No 231/2012 as an authorised food additive and categorized in “Additives other than colours and sweeteners” (8).
Evaluation in 2009
For the use of natamycin as a food additive, EFSA concluded that there was no safety concerns if only used in the surface treatment of the rind of semihard and semi-soft cheese and on the casings of certain sausages with the proposed use levels. Also, there was no concern for the induction of antimicrobial resistance. (9)
Authorised Uses And Use Levels
The following are the details for the uses and levels (10):
- only for the external treatment of uncut hard, semi-hard and semi-soft ripened cheese and cheese products: at a maximum level of 1 mg/dm2 surface, not present at a depth of 5 mm.
- only surface treatment of heat-treated (or not) dried cured sausages, at a maximum level of 1mg/kg.
UK Food Standards Agency
Categorized in “Preservatives” (11)
Food Standards Australia New Zealand
In Australia and New Zealand are all with the code number 235. (12)
Functional Class: food additives, preservative. (13)
Acceptable daily intake: ADI “0.3 mg/kg bw” set in 1976. (14)
It is common that sometimes consumers have health concerns whether natamycin is bad for our health and what are the possible side effects. It is generally considered safe but may cause some allergy symptoms when used in pharmaceuticals, such as rash, hives, itching, red, swollen, blistered and so on. (15)
Is it safe during pregnancy?
Yes, it is generally safe but better consult your doctor in the condition of use.
Frequently asked questions
Is it natural?
Yes, it is a natural preservative obtained from the fermentation process.
Is it Halal?
Yes, it is generally recognised as halal as it is permitted under the Islamic Law and fulfill the conditions of Halal. And we can find some manufacturers certificated with MUI halal.
Is it Kosher?
Yes, it is kosher pareve. E235 meets all the “kashruth” requirements and can be certified as kosher.
Is it Vegan?
Yes, it is vegan friendly as the manufacturing process without the use of animal matter or products derived from animal origin. So it is suitable to add it in the diet of vegetarians.
Is it gluten free?
Yes, it complies with the FDA’s definition of gluten free, that it does not contain wheat, rye, barley, or crossbreeds of these grains. And it is generally considered safe for people with celiac disease.
Now I think you may have a good knowledge of preservative – natamycin (E235), from the production process, uses, approved safety and possible side effects. Also, you may be clear with some common FAQs such as is it gluten free and vegan.
What kinds of food packaging have you found this additive in? Let me know in the comments.