When we talk about food contaminants we often think of pesticides, heavy metals or bacteria. But among the unwanted substances that can end up on our tables there are also mycotoxins, compounds produced by some molds that can develop on crops, during storage or in subsequent food processing phases.
Among these there are Alternaria toxins, a genus of fungi that can contaminate various agricultural productions. The European Food Safety Authority (EFSA) has once again focused on these substances, having published a new scientific assessment of the possible risks to human and animal health.
The document updates the previous opinion from 2011 and examines eight toxins. The most significant result concerns five of these, for which experts have identified genotoxic properties, i.e. the ability to cause damage to the genetic material of cells.
What are the 5 Alternaria toxins considered genotoxic
The evaluation showed that 5 of the 8 substances analyzed have genotoxic properties, i.e. they can damage the DNA of cells. These are alternariol (AOH), alternariol monomethyl ether (AME), altertoxin I (ATX-I), altertoxin II (ATX-II) and stemphyllotoxin III (STTX-III).
A particularly relevant aspect concerns AOH and AME. According to experts, both can cause DNA damage through a non-threshold mechanism. This means that it was not possible to identify an exposure level below which the potential genotoxic effect could be excluded.
For these two substances, average chronic dietary exposure estimates exceeded, in most population groups, the reference value used by EFSA for potentially mutagenic and/or carcinogenic substances acting on DNA.
This is the threshold of toxicological concern (TTC), set in this case at 2.5 nanograms per kilogram of body weight per day. It is a screening tool used to evaluate substances for which complete toxicological data are not available, not a maximum legal limit for the presence of these mycotoxins in foods.
For ATX-I, ATX-II and STTX-III, the experts confirmed the genotoxicity, but were unable to complete the exposure assessment because sufficient data on their presence in foods was lacking.
As we have already said, not all eight substances examined present the same risk profile. For altenuene and tentoxin, which were not found to be genotoxic, the estimated dietary exposure remained below the reference threshold for Cramer class III compounds, equal to 1,500 nanograms per kilogram of body weight per day.
According to EFSA, this indicates a low probability that current levels of dietary exposure could cause adverse health effects.
The case of tenuazonic acid (TeA) is different, which turned out to be the Alternaria toxin most frequently detected in foods and also the one for which the highest levels of presence were reported.
The largest quantities were identified above all in mulberries, powdered paprika and processed tomato-based products.
For TeA, however, the available scientific information on genotoxicity is not sufficient to reach a definitive conclusion. Experts have therefore not been able to establish whether this substance is capable of damaging DNA.
In which foods can we find these mycotoxins
Alternaria toxins can contaminate various agricultural crops and, consequently, find their way into the products we consume daily.
In EFSA’s assessment, the main food categories contributing to exposure include:
Estimated exposure based on body weight was generally higher in infants and young children than in adults. An element to consider when evaluating the presence of contaminants in the diet, because for the same quantity ingested, the little ones can receive a higher dose compared to their weight.
EFSA also examined possible risks to animals. For chickens for fattening, adverse effects related to exposure to AOH and AME were considered unlikely. For many other species, however, the available data do not yet allow the risk to be adequately characterized.
And the question does not just concern a theoretical evaluation. Some of the mycotoxins that came under the scrutiny of EFSA had already been identified in an analysis published by Salvagente in the November 2026 issue.
The magazine examined 30 packages of flax, sunflower and chia seeds, entrusting the analyzes to the food chemistry laboratory Foodlab of the Department of Pharmacy of the Federico II University of Naples. The researchers, coordinated by Dr. Luana Izzo, looked for 17 different mycotoxins.
Among those most frequently detected are two of the substances considered genotoxic by EFSA: alternariol (AOH) and alternariol monomethyl ether (AME).
The most significant results concerned some samples of chia seeds. In particular, the highest value of alternariol (AOH), equal to 25.73 micrograms per kilo, was detected in the Linwoods sample. As regards alternariol monomethyl ether (AME), the analyzes identified 70.69 micrograms per kilo in the organic chia seeds I love to be from Eurospin and 210.63 micrograms per kilo in the Linwoods sample.
However, there is an important clarification to correctly interpret these numbers. For alternariol and its monomethyl ether there are European indicative levels of 30 micrograms per kilo for some categories of seeds, including sunflower and sesame seeds. However, these are not maximum legal limits or thresholds that guarantee the safety of the product: they are reference values which, if exceeded, suggest investigating the causes of the contamination.
There is no specific indicative level for chia seeds. Consequently, the values of 70.69 and 210.63 micrograms per kilo detected by Salvagente cannot be defined as exceeding a regulatory limit applicable to this category of products. However, there remain results which, especially in the case of the sample with 210.63 micrograms per kilo of AME, deserve attention.
