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Mycotoxin warning for processed plant-based foods

Almost all plant-based food and drinks contain mycotoxins – naturally-occurring toxic compounds produced by fungi – and raw material monitoring should be extended, say researchers.

The levels found were lower than recommended EU guideline levels but regulatory “gaps” exist and could widen as uptake of plant-based foods increases, according to the study, published in the journal Food Control.

“[W]hile consuming these products in isolation is unlikely to pose issues, a diet solely based on plant-based foods could lead to a cumulative build-up of mycotoxins, potentially resulting in health problems if not managed properly,” the academics, led by the University of Parma in Italy and co-authored by Cranfield University, explained.

Mycotoxin levels in plant-based food and drinks

The team tested a broad spectrum of products readily available to UK consumers such as burgers, vegetarian chicken pieces, vegan sausages, oat-, almond- and soy-based milks.

Mycotoxins included in the analysis were aflatoxins (AFB₁, AFB₂, AFG₁, AFG₂), ochratoxin A (OTA), zearalenone (ZEN), fumonisins (FB₁, FB₂), deoxynivalenol (DON), HT-2/T-2, enniatins (ENNB, ENNB₁, ENNA, ENNA₁), beauvericin (BEA), alternariol (AOH), alternariol monomethyl ether (AME), and tentoxin (TEN).

Mycotoxins are particularly prevalent in plant-based foods because the raw materials those foods are made from – such as grains, legumes and seeds – can be exposed to mould during cultivation and storage.

Across the 212 plant-based meat alternatives and plant-based beverages, every one contained at least one of 19 mycotoxins, with multiple products containing more.

A high prevalence of emerging Fusarium toxins such as ENNA (93.5%), ENNA1 (93.5%), and BEA (98.9%), and the Alternaria toxins AOH (75.0%), AME (85.9%), and TEN (77.2%), was found in the plant-based meat alternatives.

Similarly, BEA, ENNB, and ENNA were frequently found in the plant-based beverages of the study, with prevalence values ranging from 71.9% to 100%.

In general, all mycotoxins were found in “significantly higher concentrations” in the meat alternatives compared to the drinks.

Mycotoxin risks and the regulatory gap

The mycotoxin levels in the tested foods were lower than the recommended EU guideline levels, reflecting the “high quality standards” of the UK food industry, according to the researchers.

However, they added, previous research studies have shown that even low levels, if consumed often, can build up exposure and lead to potential health concerns. In very serious cases, mycotoxin exposure can cause health issues like liver and kidney damage, immune system suppression, and cancer.

“The high co-occurrence observed across the samples suggests that food business operators should prioritise the management of mycotoxins in plant-based products as an integral part of their food safety systems,” the team noted in their paper.

Andrea Patriarca, senior lecturer in mycology at Cranfield University, said: “We should not be frightened or deterred from enjoying a variety of products” but raw material monitoring should be extended”.

“[A] significant concern arises when new foods enter the market, as there are currently no established regulations to monitor mycotoxins,” Patriarca explained. “The data from our research helps food safety organisations in assessing risks, particularly in complex multi-ingredient products.”

There is no specific legislation and no monitoring plans for identifying mycotoxin prevalence in plant-based beverages and meat alternatives.

The academics concluded in their paper: “It is essential to extend mycotoxin monitoring efforts to include the raw primary commodities used in plant-based meat alternatives and plant-based beverage production. Policymakers and the industry should consider the changing dietary patterns and the importance of raw material control and good manufacturing practices. Ensuring the safety of plant-based foods is essential to support their role as healthy and sustainable alternatives in the ongoing dietary transitions.”

Vegan Society: Ingredient blends may be to blame for mycotoxin content

Responding to the study, the Vegan Society said: “Mycotoxins are particularly present in legume crops. When a vegan burger, for example, is made, it may use a blend of legumes, pulses, cereals, and spices. This blending of ingredients seems to be why plant-based meat alternatives consistently show levels of mycotoxins. However, we cannot determine from this study what constitutes a potentially dangerous level of contaminated PBMA consumption.”

The Society also noted that “[t]here is no mention in the study about the transfer of mycotoxins in crops used for animal feed being passed on to farmed animals and then via their meat on to humans but this seems to be outside the scope of the research”.

Mycotoxins in plant-based alternatives: More research and testing needed

For some experts the results are ‘unsurprising’ in that mycotoxins are ubiquitous in plant food sources and processing facilities, with traditional grain, fruit, and vegetable products (and particularly coffee and beer in EU) well-recognised in the current literature.

An overview published in the International Journal of Environmental Research and Public Health in 2017 noted: “While over 300 mycotoxins have been identified, six (aflatoxins, trichothecenes, zearalenone, fumonisins, ochratoxins, and patulin) are regularly found in food, posing unpredictable and ongoing food safety problems worldwide.

Other commentators pointed out that “the real issue isn’t plants – it’s how modern food systems grow, store, and process food. And the lesson is simple: the closer food is to its natural state, the better it is for us.”

In 2024, researchers from Brazil’s University of São Paulo (USP) conducted a pilot study analysing samples of flour and rice stored in homes. The team identified high levels of harmful toxins in flour and rice, and found six mycotoxins of concern in the food samples they examined. The scientists discovered the presence of aflatoxins, fumonisins, zearalenone, T-2 toxin, deoxynivalenol, and ochratoxin A.