Mycotoxins: Invisible Dangers in Food

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At some point in your life, you’ve heard debates about healthy eating, often emphasizing organic, non-GMO, fresh, and minimally processed foods. These discussions are frequently associated with health gurus who claim to have the secret to longevity through diet. However, this focus can overshadow other important food-related topics, such as contaminants.

Mycotoxins

Mycotoxins are metabolites, small molecules, produced by filamentous fungi. As long as the environment is favorable (type of substrate, temperature, and humidity), mycotoxins can develop in our food.

We know of more than 400 compounds considered mycotoxins.

Among the best-known:

  • Aflatoxins: These mycotoxins are produced by fungi such as Aspergillus flavus, and they develop in oilseeds and cereals such as peanuts and corn. Prolonged exposure and high doses can cause immune suppression, carcinoma, and liver necrosis in both humans and animals.
  • Ochratoxin is found in foods such as oats, coffee, and wine. At least one variant is considered a nephrotoxin with carcinogenic, teratogenic, and immunosuppressive effects.
  • T2 Toxin: this mycotoxin affects several grains during the winter period and was responsible for numerous cases of food toxic aleucia (ATA) for the Soviets during the Second World War. ATA causes vomiting, diarrhea, leukopenia (an absence of white cells, aleukia), hemorrhaging, skin inflammation, and sometimes death.”
  • Zearalenone is commonly found in corn, wheat, rye, and barley. Many classify it as a mycoestrogen due to its biological similarity to estrogen. In sensitive animals such as cattle and chickens, it induces estrogenic effects, including enlargement of the uterus and breast and infertility.

In addition to the numerous health impacts, mycotoxins also affect our economies, increasing food costs from the need to discard contaminated food or feed and a loss of productivity and quality of life for humans and animals

Although it is difficult to estimate the economic costs of mycotoxins accurately, The Council for Agricultural Science and Technology (CAST), a nonprofit organization, highlighted in its 2003 Task Force Report that the United States faces a potential economic loss of approximately $932 million annually.

What’s in our food:

A pilot study that evaluated the exposure of children to food mycotoxins in the city of Ribeirão Preto, Brazil, was recently published in Food Research International.

The researchers recruited 67 volunteers (21 preschoolers, 15 school children, and 31 adolescents) with no history of chronic diseases in the last two years who attended a local community health center. Volunteers collected food samples from their homes - 213 raw or uncooked food items, including rice, wheat-based, corn, and oilseeds.

The samples were then tested [1] for the presence and quantification of a number of mycotoxins. Additionally, participants were asked to complete a food frequency questionnaire  and a 24-hour dietary recall.

The results found:

  •  Mycotoxins were found in most samples, including those that were corn or wheat-based and rice.
  • A third of the foods showed two or more mycotoxins, raising concerns about children’s health.
  • The estimated amount of mycotoxins ingested [2] was calculated and generally found to be lower than established health limits. The only exception for both children and adolescents was for the consumption of wheat-based products.

The authors concluded that stringent measures across the food chain are necessary in Brazil to enhance food safety and reduce children's exposure to food mycotoxins. These measures include better fungal control pre- and post-harvest, improving industrial and at-home storage conditions, and implementing continuous monitoring.

The authors acknowledge several limitations of the study, including its small size, which makes generalization more difficult. And inaccuracies in the 24-hour dietary recall that would impact exposure estimate.

How to reduce the risk

We can protect our at-home food supply by

  • Inspecting whole grains, nuts, and dried fruits for discoloration or mold. Discard any items showing these characteristics.
  • Ensure food is stored correctly, avoiding insects, humidity, and environments that are not too hot.
  • Do not keep food for prolonged periods.

Besides that, an article published in Food Control highlighted that crucial measures to prevent consumer exposure to mycotoxins start in the field. These measures can be categorized into pre-harvest and post-harvest strategies:

Pre-harvest strategies:

  • Implementing crop selection and rotation.
  • Adopting appropriate irrigation methods.
  • Utilizing chemical, biological, and insect control.

Post-harvest:

  • Controlling moisture content and water
  • Regulating relative humidity and temperature during storage and transport. Fungi proliferate more easily in warm and humid environments.

[1] The technique involved using a liquid chromatograph to separate the food components dissolved in a liquid. Then, those components are placed in a spectrometer which allows for the structural identification and quantification of the component..

[2] Estimated daily intake: (average concentration of mycotoxin in food) x (daily consumption) standardized for body weight

Sources:  Exposure assessment of children to dietary mycotoxins: A pilot study conducted in Ribeirão Preto, São Paulo, Brazil. Food Research International. DOI: https://doi.org/10.1016/j.foodres.2024.114087

Mycotoxins: Risks in Plant, Animal and Human Systems. Task Force Report No. 139.

Prevention and practical strategies to control mycotoxins in the wheat and maize chain. Food Control. DOI: https://doi.org/10.1016/j.foodcont.2022.108855