What are Mycotoxins? Know the Facts

The following guide explains Mycotoxins and everything you need to know.

What are Mycotoxins?

Mycotoxins are substances produced naturally by a type of fungi called molds. [1] Molds are filamentous and grow from fungal spores that settle on any warm and moist surface. [2] If the surface is rich in the organic products of decaying matter, molds grow as saprophytes, but if on the surface of living organisms, as parasites. Mycotoxins are not parasites but rather chemicals that molds produce after nutrient uptake.

Molds produce mycotoxins in quantities that are not safe for livestock or human exposure. Contact with mycotoxins may carry risk of harm (mycotoxicity) depending on whether the toxicity threshold for the mycotoxin is reached or not. Each mycotoxin has its own threshold of harm which is defined by pharmacokinetic conditions and factored into public health regulations.

The threshold of harm specified for food security differs between humans and livestock. Livestock consume a range of farm produce, but humans being atop the food chain can be exposed to mycotoxins from eating both plants and animals, including dairy.[3]

Mycotoxins enter the body through food or drinks where they cause acute poisoning, immune suppression, cancer, or damage to organs such as the gut, lungs, kidneys, and the liver.[4] Among several diseases, cancer of the liver has been closely associated with the ingestion of aflatoxin, which is one of more than five hundred known mycotoxins.[5]

Unlike mycotoxins such as penicillin and ergot alkaloids which are medicinal and have been therapeutically formulated, most mycotoxins confer no clinical benefit.[6] Worse still, molds producing mycotoxins are also infectious, spreading through food or air.[7] Thus, while disinfecting food to remove molds is important for food safety, decontamination of food to reduce if not remove mycotoxins should be prioritized.

For example, in the USA, milk considered safe to drink must not contain more than 0.5part aflatoxin per billion.[8] Aside from aflatoxin, other mycotoxins commonly encountered in food supply chains are ochratoxin A, fumonisins, nivalenol, deoxynivalenol, trichothecenes, zearalenone, mycophenolic acid, citrinin, sterigmatocystin, alternaria, and cyclopiazonic acid.[9-12]

Ochratoxin A is found in cocoa, coffee, and pulses; fumonisins are found in asparagus, dried figs, and garlic; nivalenol is found in corn and barley; deoxynivalenol is found in oat, maize, rye, and sorghum; trichothecenes are found in wheat, rice, and soybean; zearalenone is found in rye, wheat, oat, barley, sorghum, and rice; mycophenolic acid is found in cheese; citrinin is found in olives, spices, and beans; sterigmatocystin is found in moldy wheat and green coffee; alternaria is found in berries, bell peppers, apples and olives; and cyclopiazonic acid is found in cheese and cured ham.[13-18]

Crops, fruits, cereals, stone, wood, bread, cooked meal, leather, clothes, grass, and other surfaces, are easily exposed to mycotoxins from molds that grow on them, suggesting that mycotoxins are ubiquitous and impractical to eliminate from the environment.[19]

Decontamination reduces mycotoxin presence in food, water, and beverage, and is achieved by treating with ozone gas or effective alternatives.[20] Such alternatives include acetic acid, ammonia gas, calcium hydroxide, formic acid, hydrogen peroxide, phosphoric acid, propionic acid, sodium bisulfite, sodium hydroxide, sodium hypochlorite, or sorbic acid. [21-25]

Food with harmless quantities of mycotoxins is the goal of decontamination, but unfortunately this goal is never met by cooking alone. For example, cooking at 210 °C for one hour does not destroy most mycotoxins.[26]

If cooking alone is relied on for decontamination, then mycotoxins make it into the body and may take a year before being broken down into less harmful forms. Cooking and other thermal food processing methods such as frying, baking, pelleting, and roasting at best reduce mycotoxin concentrations, in contrast to fermentation methods such as malting and brewing which have been used successfully to decontaminate beverages. [27]

If decontamination is ineffective, such feeds gradually cause livestock to decline in weight and fertility, and in the production of wool, milk, and meat, leading to food shortage.[28]

Another way mycotoxins are linked to food shortage is through ergot alkaloids. When food shortage is due to unfavorable weather such as in winter, rye, the most frost-resistant cereal continues to be cultivated and is the preferred host for Claviceps purpurea, a species of mold responsible for producing ergot alkaloids.[29] Ergot alkaloids consist of indole compounds which in non-pharmacologic doses or preparations can be toxic, causing ergotism.[29]

Ergotism is characterized by several symptoms. Such symptoms include nausea, vomiting, headache, diarrhea, itching, fever, sweating, convulsions, paresthesia, muscle twitching, paranoia, and hallucination. [29] Fortunately, ergot poisoning happens more in animals than in humans.

Humans who suffer ergotism usually are migraine patients taking ergot for headache episodes and can develop a clinical feature called St. Anthony’s fire or holy fire. [29] St. Anthony’s fire describes a gangrenous lower limb that has charcoal-black discoloration and looks burnt from fire and in intense pain, but the pain reduces later as the limb dies and amputates itself painlessly. 

Medicinal ergots include ergotamine and ergometrine which are used for migraine and labor respectively. [30] Prevention of drug overdose can prevent human ergotism, while livestock ergotism is prevented by ensuring feeds are ergot-free.[31] Keeping the environment free of unsafe mycotoxin levels requires surveillance in the form of laboratory or field sampling to restrict overexposure to ergot and other mycotoxins.

Airborne mycotoxins can be detected by air sampling, and samples of livestock feeds can be tested in laboratories to assess their safety.[32] These are a few of the measures used to ensure food safety in the context of mycotoxins.

In summary, mycotoxins are naturally produced by filamentous fungi called molds. Examples are aflatoxin, ochratoxin, mycophenolic acid and ergot alkaloids. Mycotoxins are almost anywhere molds grow. Mycotoxins are in the air, in soil, in food, water and beverages. Mycotoxin levels can be tested anywhere along the food supply chain, right from grass on a cattle ranch to the air breathed in human households or offices.

Decontamination reduces the presence of mycotoxins where suspected or detected. Humans or livestock can be affected by mycotoxicity and may be treated, but death may ensue. The safety of food requires that mycotoxin levels be controlled before consumption by livestock or humans.

Mycotoxins References

1. Sengun, I., Yaman, D.B. and Gonul, S., 2008. Mycotoxins and mould contamination in cheese: a review. World Mycotoxin Journal, 1(3), pp.291-298.
2. Viitanen, H., Vinha, J., Salminen, K., Ojanen, T., Peuhkuri, R., Paajanen, L. and Lähdesmäki, K., 2010. Moisture and bio-deterioration risk of building materials and structures. Journal of Building Physics, 33(3), pp.201-224.
3. ALNABI, D.I.B.A., Al-Shawi, S.G., Al-Younis, Z.K., Swadi, W.A., Yousif, A.Y., Hafsan, H. and Mahmudiono, T., 2022. Heavy metal in the soil-grain-food path: an overview of the role of Mycotoxins in potential hazards associated with animal products. Food Science and Technology, 42.
4. Alam, S., Nisa, S. and Daud, S., 2022. Mycotoxins in Environment and Its Health Implications. In Hazardous Environmental Micro-pollutants, Health Impacts and Allied Treatment Technologies (pp. 289-318). Springer, Cham.
5. Li, F., Zhao, X., Jiao, Y., Duan, X., Yu, L., Zheng, F., Wang, X., Wang, L., Wang, J.S., Zhao, X. and Zhang, T., 2022. Exposure assessment of aflatoxins and zearalenone in edible vegetable oils in Shandong, China: health risks posed by mycotoxin immunotoxicity and reproductive toxicity in children. Environmental Science and Pollution Research, pp.1-16.
6. Tiwari, P., Kang, S. and Bae, H., 2022. Plant-endophyte associations: Rich yet under-explored sources of novel bioactive molecules and applications. Microbiological Research, p.127241.
7. Punja, Z.K., Collyer, D., Scott, C., Lung, S., Holmes, J. and Sutton, D., 2019. Pathogens and molds affecting production and quality of Cannabis sativa L. Frontiers in plant science, 10, p.1120.
8. Abbas, H.K., 2005. The costs of mycotoxin management in the United States. In Aflatoxin and food safety (pp. 26-37). CRC Press.
9. Kiseleva, M., Chalyy, Z., Sedova, I. and Aksenov, I., 2020. Stability of mycotoxins in individual stock and multi-analyte standard solutions. Toxins, 12(2), p.94.
10. Kumar, V., Basu, M.S. and Rajendran, T.P., 2008. Mycotoxin research and mycoflora in some commercially important agricultural commodities. Crop protection, 27(6), pp.891-905.
11. Wambacq, E., Vanhoutte, I., Audenaert, K., De Gelder, L. and Haesaert, G., 2016. Occurrence, prevention and remediation of toxigenic fungi and mycotoxins in silage: A review. Journal of the Science of Food and Agriculture, 96(7), pp.2284-2302.
12. Tangni, E.K., Pussemier, L. and Van Hove, F., 2013. Mycotoxin contaminating maize and grass silages for dairy cattle feeding: current state and challenges. J. Anim. Sci. Adv, 3(10), pp.492-511.
13. Zinedine, A. and Mañes, J., 2009. Occurrence and legislation of mycotoxins in food and feed from Morocco. Food Control, 20(4), pp.334-344.
14. Logrieco, A., Bottalico, A., Mulé, G., Moretti, A. and Perrone, G., 2003. Epidemiology of toxigenic fungi and their associated mycotoxins for some Mediterranean crops. In Epidemiology of mycotoxin producing fungi (pp. 645-667). Springer, Dordrecht.
15. Rahmani, A., Jinap, S. and Soleimany, F., 2009. Qualitative and quantitative analysis of mycotoxins. Comprehensive reviews in food science and food safety, 8(3), pp.202-251.
16. Pitt, J.I. ed., 2012. Improving public health through mycotoxin control (pp. 31-85). Lyon, France: International Agency for Research on Cancer.
17. Afsah‐Hejri, L., Jinap, S., Hajeb, P., Radu, S. and Shakibazadeh, S.H., 2013. A review on mycotoxins in food and feed: Malaysia case study. Comprehensive Reviews in Food Science and Food Safety, 12(6), pp.629-651.
18. Bhunia, A.K., 2018. Molds and mycotoxins. In Foodborne Microbial Pathogens (pp. 167-174). Springer, New York, NY.
19. Udomkun, P., Mutegi, C., Wossen, T., Atehnkeng, J., Nabahungu, N.L., Njukwe, E., Vanlauwe, B. and Bandyopadhyay, R., 2018. Occurrence of aflatoxin in agricultural produce from local markets in Burundi and Eastern Democratic Republic of Congo. Food Science & Nutrition, 6(8), pp.2227-2238.