Moulds and mycotoxins: invisible hazards in food

Moulds grow on organic material and produce a wide range of chemical substances. Some of these are mycotoxins — toxins produced by mould‑forming fungi that serve, among other things, as protection against predators. In humans, they can cause acute symptoms such as gastrointestinal problems, but they can also have long‑term effects, including liver damage or an increased risk of cancer.

One of the best‑known examples of mycotoxins is aflatoxins, which are produced by certain Aspergillus species. Aflatoxins are frequently found in grains, nuts and some fruits. These mould‑derived toxins are highly hepatotoxic and carcinogenic and are among the best‑studied mycotoxins. “For many other mould toxins, however, we know very little about their exact effects in the body — for example, in the case of the so‑called Alternaria toxins,” says Marx‑Stölting. The aim of the PARC research partnership is to close such data gaps.

Mould toxins even when no mould is visible

Traces of mould toxins are repeatedly found in many other plant-based foods — even when no mould growth can be seen on the products themselves. Besides tomatoes, grains, nuts, peppers and sunflower seeds are affected, as well as products made from them, such as bread, muesli and plant-based drinks. The establishment of maximum permitted levels for such substances by the EU helps to minimise health risks. Compliance is monitored through regular testing as part of quality checks carried out by manufacturers and retailers, as well as through spot checks by official food control authorities. This helps ensure that health risks from mycotoxins in food are reduced as far as possible.

A central problem is that mycotoxins are heat‑stable. “The moulds themselves are killed by heat, but the toxins remain, because they are chemically very stable,” explains Marx‑Stölting. Cooking, baking or frying therefore generally does not destroy these toxins. Once a food product is contaminated, the toxins usually remain present even after preparation.

For this reason, the BfR recommends discarding mouldy foods entirely. Cutting off or scraping away visibly affected areas is not sufficient, as mycotoxins may already be distributed throughout the entire product and are not visible to the naked eye. This recommendation applies especially to soft or water‑rich foods such as bread, fruit, vegetables or jam.

Research partnership aims to close data gaps

While extensive data already exist for some mycotoxins, such as aflatoxins, there are still significant knowledge gaps for many other mould toxins. This is precisely where the EU project PARC comes in. The project brings together research institutions, assessment authorities and other organisations from across Europe. “The basic idea is that everyone works together, prevents the same work from being done twice and ensures that results are interpreted jointly,” says Marx‑Stölting. “This allows us to reach results — and decisions — quickly and efficiently.” The aim of the partnership is to improve the data basis for the scientific assessment of health risks posed by industrial chemicals as well as certain naturally occurring chemical substances such as mycotoxins.

Link to the full podcast episode:
https://podcast.bfr.bund.de/12-mykotoxine-uber-schimmelpilze-und-schimmelpilzgifte

Quotes and original sound bites from the podcast episode may be used freely provided the source is cited.

About “Risiko” and “Risiko kompakt”

Daily newspapers, news portals and social media posts constantly warn about new health risks: plasticisers in sunscreen, microplastics in the body or alleged contaminants in food. But what is really behind these supposed dangers? And how great is the risk for me personally? In our German‑language podcast formats “Risiko” and “Risiko kompakt” (“Risk” / “Risk compact”), we get to the bottom of such topics — calm, scientifically sound and easy to understand. In “Risiko”, this happens in relaxed, half‑hour conversations. “Risiko kompakt”, on the other hand, focuses on the essence of a story and uses original audio from experts to explain the most important facts and background.

About the BfR

The German Federal Institute for Risk Assessment (BfR) is a scientifically independent institution within the portfolio of the German Federal Ministry of Agriculture, Food and Regional Identity (BMLEH). It protects people's health preventively in the fields of public health and veterinary public health. The BfR provides advice to the Federal Government as well as the Federal States (‘Laender’) on questions related to food, feed, chemical and product safety. The BfR conducts its own research on topics closely related to its assessment tasks.