Mycotoxins are naturally occurring toxins produced by certain molds (fungi) that are found naturally all over the world. They can contaminate food crops and pose a serious health threat to humans and livestock. Food crops can become contaminated both before and after harvesting. Pre-harvest contamination with aflatoxins is mainly limited to corn (maize), cottonseed, peanuts, and tree nuts. Post-harvest contamination can be in crops such as coffee, rice, and spices. Improper storage under conditions that favor mold growth (warm and humid storage environments) can typically lead to levels of contamination much higher than those found in the field. (WHO, 2018)
In humans, long-term exposure can have serious health consequences including:
aflatoxins are potent carcinogens and may affect all organ systems, especially the liver and kidneys.
aflatoxins have the potential to cause birth defects in children.
growth in children may become stunted.
aflatoxins cause immunosuppression, therefore may decrease resistance to infectious agents, for example HIV and tuberculosis.
In animals, aflatoxins cause a variety of adverse effects:
In chickens, liver damage, impaired productivity, and reproductive efficiency, decreased egg production, inferior eggshell quality, inferior carcass quality and increased susceptibility to disease.
In pigs, liver damage.
In cattle, reduced weight gain, liver and kidney damage, reduced milk production.
Mycotoxins and human disease: A largely ignored global health issue was published in 2010 in the journal Carcinogenesis. This shameful situation continued until recently. Increased attention to aflatoxins was triggered by the negative effects of climate change on increased production of mycotoxins/aflatoxins in human food and in animal feed.
Climate Change: Unpacking the Burden on Food Safety (2020) is a comprehensive report published by the Food and Agriculture Organization (FAO). It includes extensive coverage of the negative effects on the safety of the global food supply caused by climate change effects on foodborne pathogens and parasites, algal blooms, heavy metals, methylmercury, pesticides, and mycotoxins. This report states:
Mycotoxin contamination in staple crops is a major health concern and barrier to international trade. Some of the important factors that influence mycotoxin production – temperature, relative humidity, and crop damage by pests – are
affected by climate change. As warmer temperatures make cooler temperate zones conducive to agriculture, they could open new habitats for pests and fungal species. There are already reports of the emergence of mycotoxins in areas with
no history of prior contamination. A number of these regions lack the capacity for outbreak management making it difficult to curtail damage to the local economies and public health. Inadequate storage and transportation facilities under climate change conditions are also bound to affect mycotoxin production and dissemination.
WHO (2018) emphasizes that control of aflatoxins requires an integrated approach at all stages from the field to the table. This includes:
Targeted plant breeding practices.
Enhancement of host plant resistance, and biological control methods, coupled with post
harvest technologies such as proper drying and storage of potentially affected crop products, as well as development of appropriate alternative uses to retain at least some economic return on value of damaged crop.
Therefore, by removing the sources of contamination, promoting better agricultural and storage techniques, ensuring adequate resources are available for testing and early diagnosis, enforcing strict food safety standards, informing and educating consumers and (small/subsistence) farmers, promoting better livestock feeding and management, and
creating general awareness about personal protection, are some of the ways in which national authorities can help to control aflatoxins.
We are pleased to see extension services in U.S. universities getting more engaged in mycotoxin/aflatoxin information. Michigan State University Extension posted in August 2021: Corn silage is rarely analyzed for mycotoxins, so contamination remains largely unnoticed. An Michigan State University project aims to resolve this mycotoxin dilemma and help growers reduce possible losses. Growers can submit corn silage samples for free mycotoxin analysis.
International food aid agencies are increasingly concerned about the distribution of corn/maize, rice, and other foods to people in need of food in developing countries. Professor Felicia Wu, Hannah Distinguished Professor of Food Science and Human Nutrition at Michigan State University explains why in a paper published in Environmental Health Perspectives (2013):
Aflatoxin monitoring is rare in developing countries, except for grains and nuts headed for export. Even in countries where standards for aflatoxin exist, they may not always be enforced. Subsistence farmers just eat what they grow. Lack of awareness about aflatoxin is a serious issue.
Aflatoxin Poisoning in Pets (FDA, 2021) has useful advice for pet owners and for veterinarians. Recently the FDA has reported the death of dogs fed aflatoxin contaminated dog food.
Mycotoxins/Aflatoxins are finally receiving the attention and regulations they deserve. Further useful information is available on the websites of FDA, CFIA, EFSA, WHO, FAO.