Natamycin | whatsinit

About

What it is and where it shows up.

Natamycin is a natural polyene macrolide antifungal produced by the soil bacterium Streptomyces natalensis; it targets ergosterol in fungal cell membranes to inhibit mould and yeast growth. It is used as a surface preservative on cheeses, cured sausages, yoghurt, juices, and wines to extend shelf life and prevent mycotoxin contamination.

Safety summary

The regulatory and scientific consensus.

Natamycin has very low oral toxicity because gastrointestinal absorption is negligible; WHO/JECFA established an ADI of 0.3 mg/kg body weight per day. No evidence of mutagenicity, allergenicity, or carcinogenicity has been found in authoritative reviews by EFSA (2009), JECFA, and FDA. A minority scientific concern exists around the use of soluble cyclodextrin-natamycin complexes in beverages, which may foster polyene resistance in intestinal Candida spp., though EFSA concluded there is no safety concern for antimicrobial resistance induction at permitted food-additive use levels.

Regulatory landscape

What food-safety regulators have decided.

Jurisdiction	Status	Note
EFSA (European Food Safety Authority) (European Union)	Approved	Permitted for surface treatment only of semi-hard and semi-soft ripened cheeses and dry cured sausages at ≤1 mg/dm² in the outer 5 mm; must not be detectable at 5 mm depth. Governed by Directive 95/2/EC and Regulation (EC) No 1333/2008. EFSA 2009 re-evaluation confirmed no antimicrobial resistance concern.source
Food Standards Agency (FSA) / Food Standards Scotland (FSS) (United Kingdom)	Approved	Retained under Assimilated Regulation (EC) No 1333/2008 Annex III post-Brexit; same scope as EU: surface treatment of cheese and cured sausages only.source
FDA (Food and Drug Administration) (United States)	Approved	Permitted as an antimycotic agent under 21 CFR 172.155 for surface application on cut or sliced cheese; also subject to GRAS notifications (GRN No. 517). It is the only antifungal food additive with GRAS status.source

Who should approach with care

Whose guidance would steer them away.

Other — Individuals on antifungal therapy with polyene drugs (e.g., amphotericin B) should exercise caution, as high intestinal exposure from soluble natamycin formulations in beverages and yoghurt may theoretically foster Candida resistance to these life-saving antifungal agents, per PMID:25862309.

Ibd — Patients with inflammatory bowel disease may have altered gut flora and mucosal permeability; the potential for natamycin to disrupt gut microbiota equilibrium (noted as a knowledge gap by PMC12845236) warrants medical consultation before regular high-dose intake.

Infants — Long-term, developmental, and microbiome-focused safety data for infants are lacking (PMC12845236); natamycin should only be present in infant-targeted products where specifically evaluated and authorised by regulators.

Research citations

The sources behind this verdict.

1PubMed. Natamycin as a safe food additive to control postharvest green mould and sour rot in citrus, 2022. pubmed.ncbi.nlm.nih.gov
2PubMed. Natamycin: a natural preservative for food applications—a review, 2021. pubmed.ncbi.nlm.nih.gov
3PubMed. Does use of the polyene natamycin as a food preservative jeopardise the clinical efficacy of amphotericin B? A word of concern, 2015. pubmed.ncbi.nlm.nih.gov
4EFSA. Scientific Opinion on the use of natamycin (E 235) as a food additive, 2009. efsa.europa.eu
5WHO. Evaluation of Certain Food Additives – Twentieth Report of the Joint FAO/WHO Expert Committee on Food Additives (JECFA), 1976. fao.org

Independently researched5 citations