Natamycin
Last reviewed October 18, 2026 · Evidence strength: Very limited · How we grade evidence
In plain words: Natamycin is a natural mold-fighter used on cheese surfaces and some sausages. It doesn't kill bacteria, so it doesn't drive the kind of antibiotic resistance people worry about, and very little is absorbed. No need for concern.
Also listed on labels as: Natamycin, Pimaricin, E235
What is it, and why is it in food?
Natamycin is made by soil bacteria and stops molds and yeasts. It's used on the surface of cheese, shredded cheese, some deli items and dry sausages. US rules limit it to 20 mg per kg on cheese.
What does the science say?
| The popular claim | "Natamycin is an antibiotic sprayed on cheese that promotes antibiotic resistance." (A common online claim; none of the five experts we reviewed made it.) |
| Our verdict on that claim | Not supported |
| Evidence strength | Very limited: an opinion piece raised a theory; regulators see no concern from surface uses. |
| Kinds of studies | Expert opinion, regulatory reviews |
- Resistance: Natamycin is an antifungal, not an antibacterial. A 2015 opinion piece suggested that mixing it throughout yogurt or drinks could, in theory, help Candida yeast become resistant to related medicines. That's untested.1
- Absorption: Very little is absorbed from the gut.
What do regulators say?
- EFSA (2009) saw no concern for resistance from use on cheese and sausage surfaces.2
- FDA: permitted on cheese up to 20 mg per kg.3
Who should be careful?
- No group needs to avoid it.
How common is it in US foods?
In our check of USDA's Branded Foods database, 6,612 of 438,129 US packaged foods with an ingredient list name natamycin (about 1.5%, or roughly 1 in 66).4 It shows up most often in: cheese (3,011); other deli (460); pickles, olives, peppers & relishes (357); savoury bakery products (226); lunch snacks & combinations (204). Almost half are cheeses, mostly shredded. These are label records companies sent to USDA, mostly in 2021 to 2023, so some products have changed since. Counts come from a text match of ingredient lists and are approximate.
Swaps and tips for families
- No swap needed. Block cheese you shred yourself often skips it, if you prefer.
Beyond the plate: related non-food exposures
Natamycin is used medically as eye drops for fungal eye infections.
Frequently asked questions
Is natamycin an antibiotic?
It's an antifungal. It doesn't kill bacteria, so it doesn't contribute to bacterial antibiotic resistance.
Is natamycin safe?
Yes, at the amounts used. Very little is absorbed, and regulators see no concern.
Why is natamycin in shredded cheese?
Shredded cheese has more surface area, so it molds faster. Natamycin keeps mold off.
Related guides
Sources
Every source below was checked against PubMed, the publisher or the official page by our research team in October 2026.
- Does use of the polyene natamycin as a food preservative jeopardise the clinical efficacy of amphotericin B? A word of concern. International journal of antimicrobial agents, 2015. PubMed 25862309 · doi:10.1016/j.ijantimicag.2015.02.011
- Scientific Opinion on the use of natamycin (E 235) as a food additive. EFSA Journal, 2009. doi:10.2903/j.efsa.2009.1412
- 21 CFR 172.155 Natamycin (pimaricin). Link
- FoodData Central, Branded Foods dataset (release 2026-04-30). U.S. Department of Agriculture, Agricultural Research Service, 2026. Link
This guide is for general education. It is not medical advice and does not replace advice from your doctor, pediatrician, allergist or registered dietitian. If you think you or your child reacted to a food, talk to a health professional. Research changes; we review these pages when new evidence or rules come out. Last reviewed October 18, 2026. Spotted an error? Email [email protected].