Introduction
Certain molds create harmful metabolites called aflatoxins, which can contaminate food and pose serious health risks to people. Aflatoxin exposure over an extended period of time can result in aflatoxicosis, a potentially fatal illness that mostly affects the liver. These poisons can contaminate crops during harvest, storage and transportation. They are primarily present in soil, hay, decomposing plants and grains. Aflatoxin exposure is a major public health concern since it can happen at any time in life and has been connected to hepatocellular carcinoma (
liver cancer) and other illnesses. People of all ages are at risk from this silent hazard, but children are particularly at risk because they are more likely to consume foods contaminated with aflatoxin (Alameri et al., 2023).
Aflatoxins pose serious global public health and economic concern because of the significant negative health and economic problems that they impact on farmers and consumers worldwide (Jallow et al., 2021). Commodities grown in the tropics and subtropics, such as cottonseed, soy, rice, sorghum, barley, rye, wheat, groundnuts, and maize, are mostly linked to aflatoxins. A variety of goods such as cereals, nuts, spices, figs and dried fruit, contain aflatoxins. However, the two crops with the highest risk of aflatoxin worldwide are maize and groundnut (Wolde, 2017). These crops are typically more contaminated with aflatoxin due to aflatoxigenic fungal infections. As a result, both humans and animals are exposed to this poison at larger levels, which leads to serious health and financial issues (Wolde, 2017). It has caused the global economy to lose billions of dollars by polluting products including cotton, groundnuts, maize and chilies and having a severe negative impact on both human and animal health. As of now, more than eighteen varieties of aflatoxins have been identified, with the most common and deadly being aflatoxins B1, B2, G1, and G2 (Shabeer et al., 2022). A variety of fungal species, primarily Aspergillus, Alternaria, Fusarium and Penicillium, create mycotoxins which are secondary metabolites. Around the world, 25% of food is contaminated with mycotoxins, according to the Food and Agriculture Organization (FAO)(Shabeer et al., 2022).
According to the Bible and other documented accounts of food-related illnesses and deaths, mycotoxins have plagued people for a very long time, possibly since the dawn of agricultural production for human use (Jallow et al., 2021). Among other health hazards, prolonged exposure to AFs has been connected to oxidative stress, liver cancer and improper prenatal growth. There is currently no universally understood technique to lower AF levels in food and feed, despite the fact that a number of technologies, including physical, chemical and biological controls, have been used to lessen the toxic effects of AF. The only mitigation is early toxin detection in the management of AF contamination (Alameri et al., 2023).
What is Aflatoxin?
Aflatoxins are various poisonous carcinogens and mutagens that are produced by certain species of molds primarily Aspergillus flavus and Aspergillus parasiticus. Certain Aspergillus flavus and Aspergillus parasiticus strains produce the fungal compounds known as aflatoxins (Negash, 2018). With a particular affinity for cereals and nuts, aflatoxins are a class of structurally related poisonous, mutagenic and carcinogenic mycotoxins that contaminate a wide range of food and agricultural items. From a chemical perspective, certain fungal species produce chemicals called mycotoxins as secondary metabolites in the field and while agricultural products are being stored. From the perspective of food safety, the B-series (aflatoxin B1 and B2), G-series (aflatoxin G1 and G2), and M-series (aflatoxin M1; Figure 1) are the most significant of the several aflatoxins that have been found as analogs and derivatives (Jallow et al., 2021). Aflatoxin B1 is considered the most toxic and carcinogenic, linked to liver cancer and other health complications particularly in regions with high dietary exposure. Aflatoxin M1, a derivative of B1, is found in milk and dairy products when livestock consume contaminated feed. According to the USDA (U.S. Food and Drug Administration), "They are probably the best known and most intensively researched mycotoxins in the world. Aflatoxins are considered unavoidable contaminants of food and feed, even where good manufacturing practices have been followed.
Aflatoxin Contamination
The process of aflatoxin production is greatly influenced by abiotic parameters such temperature, water activity, pH, carbon, and nitrogen, but temperature and water activity are particularly important for aflatoxin contamination. These two circumstances have a significant impact on the activation of the aflatoxin-producing gene cluster in addition to promoting the growth of fungi that produce aflatoxin, especially A. flavus(Shabeer et al., 2022). According to the RASFF (Rapid Alert System for Food and Feed) database, the majority of aflatoxin contamination in 2020 was found in peanuts, rice, nuts (almonds, hazelnuts, and pistachios), spices, and dried figs, with levels as high as 1000 μg/kg. Poor food control procedures during the current COVID-19 epidemic were the primary cause of this high concentration(Shabeer et al., 2022). Diet and climate have a crucial role in the development of aflatoxin contamination of food and eventual human exposure. A significant amount of the worldwide aflatoxins burden is carried by countries with warmer climates and staple foods that are sensitive to aflatoxins (Jallow et al., 2021). Due to the prevalence of mycotoxigenic molds, mycotoxins, such as aflatoxin, contaminate a wide range of crops and foods globally, particularly those cultivated in tropical areas(Jallow et al., 2021).
According to the US Grains Council's Corn Harvest Quality Report 2018–2019, 98% of the 181 maize samples that were tested for aflatoxin had undetectable levels. This is comparable to the two years prior, when a mere 0.6% (1) of the 181 samples had aflatoxin levels above the 20 ppb (parts per billion) FDA regulatory limit. Aflatoxin poisoning can also affect rice (Oryza sativa L.), one of the most popular grains in the world. The primary environment for rice production is one that supports the growth of fungi and the formation of aflatoxin. Therefore, the field where grains are contaminated by aflatoxin-producing fungi is where their aflatoxin contamination begins (Jallow et al., 2021). Once contaminated crops are harvested, improper drying, poor storage conditions, and inadequate pest control can exacerbate aflatoxin levels. For instance, storing grains in damp or unventilated environments creates ideal conditions for mold proliferation. These contaminated crops are then processed into everyday food products such as flour, cooking oil, peanut butter, and animal feed (Alameri et al., 2023).
In homes, aflatoxins can be consumed through various means. Common sources include cereals, nuts and spices used in cooking as well as milk, meat and eggs derived from livestock that have ingested aflatoxin-contaminated feed. Additionally, traditional food processing methods such as grinding and fermentation often fail to eliminate aflatoxins, leaving these toxins in prepared meals. In regions where food safety standards are poorly enforced, the risk of exposure through both raw and processed foods is particularly high (Alameri et al., 2023). This pathway highlights the importance of implementing proper agricultural practices such as drying crops thoroughly and using hermetic storage systems as well as purchasing food from trusted sources. By addressing aflatoxin contamination at each stage of the agricultural and food supply chain, the risk of exposure in households can be significantly reduced (Alameri et al., 2023).
Health risks associated with aflatoxin
Among other health hazards, prolonged exposure to Aflatoxins (AFs) has been connected to oxidative stress, liver cancer and improper prenatal growth. There is currently no universally understood technique to lower AF levels in food and feed, despite the fact that a number of technologies including physical, chemical and biological controls have been used to lessen the toxic effects of AF. The only mitigation is early toxin detection in the management of AF contamination (Wolde, 2017). Aflatoxins can lead to several health problems such as damage to the liver. The liver is the chemical target of aflatoxins which can result in acute liver damage, bleeding, edema and digestive issues. Cancer is also a health risk of aflatoxin. Hepatocellular carcinoma (HCC)(liver cancer) can result from aflatoxins which are carcinogenic and mutagenic. In regions of Asia and Africa where it causes almost 70% of cancer related fatalities, HCC is a leading cause of cancer related deaths. Immune suppression; Aflatoxin exposure over time can impair immunity. Anomalies in fetal growth is also another one of aflatoxin health risks. Exposure to aflatoxin can impact fetal growth and raise the risk of preterm birth and pregnancy loss. Other medical conditions are malnutrition, reproductive issues and stunted growth and development are further effects of aflatoxin exposure.
How to avoid aflatoxin
To avoid aflatoxin, you can:
Dry crops before storing to ensure they are properly dried to prevent aflatoxin development.
Store crops in a dry place to keep moisture levels in stored grains below 12–13%.
Control insects and rodents to keep their activity to a minimum. Insects can create favorable conditions for fungal growth, and rodents can increase moisture levels through urination.
Avoid temperature fluctuations that can cause condensation to form, which can lead to fungal growth and aflatoxin formation.
Use covered containers to protect peanuts from additional moisture.
Sort and dispose of visibly moldy kernels before storing.
Buy commercial brands of nuts and nut butters.
Discard discolored or shriveled nuts.
Clean the inside of the refrigerator every few months with 1 tablespoon of baking soda dissolved in a quarter of water. Rinse with clear water and dry.
Scrub visible mold (usually black) on rubber casings using 3 teaspoons of bleach in a quarter of water.
Keep dishcloths, towels, sponges, and mops clean and fresh. A musty smell means they're spreading mold around. Discard items you can't clean or launder.
Keep the humidity level in the house below 40%.
Conclusion
Aflatoxin is a type of mycotoxin produced by Aspergillus mold. Aflatoxin is the most well-known, researched mycotoxin and is one of the most dangerous and poisonous mycotoxins in the world. Aflatoxins are found in the soil as well as in grains, nuts, dairy products, tea, spices and cocoa, as well as animal and fish feeds (Negash, 2018). Aflatoxins induce a variety of illnesses and are poisonous to both humans and animals. People are typically exposed to aflatoxin in two basic ways. The first occurs when a person consumes large amounts of aflatoxins quickly. Among other things, this may result in liver damage, liver cancer, mental impairment, nausea, vomiting, and even death. Aflatoxin poisoning can also occur when a person consumes trace amounts of aflatoxins over an extended period of time. This could occur if a person consumes a modest quantity of aflatoxin. Among other things, this may result in DNA and RNA mutation, liver cancer, and impairment of growth and development (Wolde, 2017).
References
Alameri, M.M. et al. (2023) ‘Aflatoxin Contamination: An Overview on Health Issues, Detection and Management Strategies’, Toxins, 15(4), pp. 1–16. Available at: https://doi.org/10.3390/toxins15040246.
Jallow, A. et al. (2021) ‘Worldwide aflatoxin contamination of agricultural products and foods: From occurrence to control’, Comprehensive Reviews in Food Science and Food Safety, 20(3), pp. 2332–2381. Available at: https://doi.org/10.1111/1541-4337.12734.
Negash, D. (2018) ‘A review of aflatoxin: occurrence, prevention, and gaps in both food and feed safety’, Journal of Nutritional Health & Food Engineering, 8(2). Available at: https://doi.org/10.15406/jnhfe.2018.08.00268.
Shabeer, S. et al. (2022) ‘Aflatoxin Contamination, Its Impact and Management Strategies: An Updated Review’, Toxins, 14(5), pp. 1–24. Available at: https://doi.org/10.3390/toxins14050307.
Wolde, M. (2017) ‘Effects of aflatoxin contamination of grains in Ethiopia’, International Journal of Agricultural Sciences, 7(4), pp. 1298–1308. Available at: www.internationalscholarsjournals.org.
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