Threats Of Mycotoxin Contamination

Globally, the UN Food and Agriculture Organization (FAO) estimates that approximately 25 per cent of the world's food crops are contaminated with mycotoxins. However, the Eskola et al. 2020 study challenges this figure, suggesting 60–80 per cent of crops have detectable levels of mycotoxins. Multiple research reports indicate on a global level, 30–88 per cent of food-feed samples are co-contaminated with multiple mycotoxins. 

Assessing the global economic impact of mycotoxins is complex and varies annually. In the United States and Canada alone, mycotoxins cause economic damage of up to $5 billion annually. This economic detriment arises from management costs, reduced crop yields, and both human and animal adverse health effects. Livestock producers face increased production expenses, impaired animal immunity, decreased productivity, and higher veterinary costs due to mycotoxin-contaminated feeds.

Health hazards

Mycotoxins are naturally occurring toxins produced by specific fungi (moulds) species, notably Aspergillus, Fusarium, Penicillium, and Byssochlamys. To date, over 500 distinct mycotoxins have been identified, many of which are under rigorous scientific scrutiny due to their health hazards. Among the most hazardous are aflatoxins, ochratoxins, zearalenone, patulin, sterigmatocystins, ergotamine, deoxynivalenol (DON), fumonisins, and trichothecenes, including T-2 and HT-2 toxins. They pose significant risks to public health and veterinary care, emphasizing the need to address mycotoxin contamination for food safety and security. Aflatoxins alone affect around 4.5 billion people in underdeveloped countries, with aflatoxicosis ranked as the sixth top health threat.

Fungal infestations in staple crops such as rice, wheat, and maize lead to mycotoxins biosynthesis. Trichothecenes, a mycotoxin, have been detected in corn, wheat, barley, oats, rice, rye, and vegetables. Mycotoxin damage extends beyond raw agricultural products to encompass processed food items, including bread, juices, dried fruits, nuts, coffee, eggs, meat, fish, and milk. Contamination occurs at various stages, including crop growth, post-harvest handling, storage, transportation, and processing. Exposure routes encompass dermal contact, ingestion, and inhalation, resulting in a spectrum of diseases referred to as mycotoxicoses. 

Exposure to mycotoxin-contaminated food feed can lead to acute and chronic health issues. Acute effects are skin irritation, nausea, vomiting, and gastrointestinal distress. Chronic exposure is concerning, as it can result in liver damage, immunosuppression, and developmental disorders. Some mycotoxins disrupt endocrine function and fertility. Scientific literatures report that aflatoxins, commonly found in rice, maize, nuts, and milk, are linked to liver cancer. Patulin, prevalent in moldy apples and apple juices, remains toxic even after pasteurization, causing nausea and genotoxicity. Similarly, fumonisins have been linked to esophageal cancer and neural tube defects, while ochratoxin A has been implicated in kidney disease and testicular cancer. Zearalenone, a mycotoxin produced by Fusarium species, has detrimental effects on ovulation and semen production. 

The International Agency for Research on Cancer classifies mycotoxins by carcinogenic risks in 2012, with aflatoxins as Group 1 carcinogens and ochratoxin A and fumonisin B1, B2 as possible human carcinogens (Group 2B). Patulin and DON remain unclassified due to limited data. 

With increasing evidence linking mycotoxins to major health issues, their impact on vulnerable Nepali populations, particularly children and pregnant women, cannot be ignored.

Nepal has made significant progress in reducing malnutrition, lowering stunting and wasting, but recent data show stagnation, with national stunting and wasting rates at 36 percent and 10 percent, respectively. The government aims to reduce stunting and wasting prevalence to 15 and 4 percent by 2030. A key yet often overlooked factor contributing to this stagnation is mycotoxin contamination in food feed. Mycotoxins may exacerbate nutritional deficiencies, interacting with other risk factors such as poor maternal nutrition, inadequate hygiene, and limited dietary diversity. This issue demands urgent attention as mycotoxins exacerbate food insecurity and public health threats in Nepal.

Despite extensive mycotoxin global research, studies on mycotoxins in Nepal remain limited. Current research primarily focuses on aflatoxin contamination in select food commodities, with inadequate attention given to surveillance and risk reduction strategies. Scientific studies have revealed high levels of mycotoxin contamination in Nepali maize. A 2008 study by Gautam et al. reported aflatoxin B1 in 42 per cent of maize samples from the Kathmandu Valley. A 2013 government technical report from aflatoxin survey found 70 per cent contamination of 141 maize samples across Nepal. Additionally, Desjardins and Busman's Mycotoxin Research (2006) reported 40 per cent of 46 maize samples contained high levels of fumonisin B1.

Safety measures

The Department of Food Technology and Quality Control, the government's food safety assurance body, reports one-fifth of maize samples exceed Nepal's maximum permitted limit (MPL: 20 microgram per kilogram) for aflatoxins as established by the Nepal Government. Currently, the government has set MPL only for aflatoxins. Mycotoxins pose a serious but often overlooked threat to food security and public health. Nepal must establish best practices, guidelines, and policies to assess mycotoxin risks and implement effective safety measures.

Nepal must strengthen food safety policies by enforcing stricter regulations on post-harvest handling, storage, and processing to prevent fungal contamination. Establishing MPL for additional mycotoxins (ochratoxins, fumonisins, DON) is essential, and routine monitoring is recommended. A national surveillance framework, supported by government, research institutions, and the private sector, is urgently needed for effective mitigation. Educating farmers, enforcing regulations, and harmonising policies with global standards can reduce mycotoxin-related threats. A multipronged approach combining scientific advancements, regulatory enforcement, and public awareness is essential to ensuring food-feed safety, quality, and a healthier future for Nepal.

Authors are researchers at the Nexus Institute of Research and Innovation (NIRI).