Natamycin

Additive · E235

Natamycin, also called pimaricin or E 235, is a preservative made by bacteria that limits mold and yeast growth. It is used in some cheeses and other permitted foods. Allowed amounts and whether treatment must stay on the surface vary by country.

Also known as

natamycin · pimaricin · Tennecetin · E235 · E 235 · INS 235

Why PRūF tracks it

Regulatory studies support permitted exposure, while limited human dietary evidence and laboratory fungal-tolerance findings leave uncertainty; a small adverse reproductive report has major methodological inconsistencies that prevent reliable hazard interpretation.

Read the research

Natamycin controls molds and yeasts by binding a component of fungal membranes. It is poorly absorbed after swallowing, but that does not rule out effects within the gut. In 2024, international experts reaffirmed an acceptable daily intake of 0–0.3 milligrams per kilogram of body weight. New rat studies supported that value, and the exposure estimates reviewed were below it.

Older reproductive and long-term studies were broadly reassuring, though their limitations and the scarcity of human dietary studies remain relevant. A small 2025 rat report described reproductive tissue changes at a low stated dose, but conflicting methods and a mismatch in the reported laboratory reagent make its conclusions unreliable. Separate experiments showed that prolonged laboratory exposure can increase tolerance in some fungi; they did not demonstrate that eating natamycin causes resistant infections. Food rules differ.

U.S. regulations specify a cheese limit, while separate GRAS notices cover particular yogurt and beverage uses. European permissions emphasize surface treatment of specified cheeses and dried cured sausages. These conditions limit exposure; they do not establish safety at every possible amount or in every formulation.

Research reviewed on September 5, 2026 · 11 sources