Aflatoxin Moulds
What is aflatoxin?
Aflatoxin is a sort of poison produced by the mould Aspergillus flavus which leads to severe health effects on humans and animals alike. Aspergillus flavus is the most common specie in Africa and Asia, highly toxic group of mycotoxins.
Aflatoxin accumulating fungi can infect groundnut during the production season as well as during post-harvest handling. Pre-harvest infection by Aspergillus flavus and consequent Aflatoxin contamination is more important in the semi-arid tropics, especially when drought occurs just before harvest.
Drought-stressed plants lose moisture from pods and seeds; physiological activity is greatly reduced. Both factors increase susceptibility to fungal invasion. Poor harvesting and storage conditions can lead to rapid development of the fungi and thus high toxin can be produced.
If you noticed mold growing on your bread, you would toss it out, right? What if the mold on that bread was invisible? Further, what if that invisible mold was one of the most carcinogenic, toxic naturally occurring substances known to humankind? This scenario is not far from the truth. The deadly mycotoxin called aflatoxin is disturbingly common in our foods today.
Aflatoxin moulds in peanuts
As alarming as it sounds, even apparently healthy foods can kill you. Aflatoxins are among the most poisonous natural compounds on the planet, and aflatoxicosis is what happens if you ingest enough. Aflatoxin B1 (the most common aflatoxin) is the most potent naturally occurring liver carcinogen known to humankind.
It’s estimated that about 4.5 billion people are exposed to aflatoxins each year in developing countries, although the numbers are largely unmonitored and on the rise. People consuming normal-appearing corn, peanuts, or grain have become critically ill and even died from acute aflatoxin poisoning, which can cause life-threatening hemorrhage, liver damage, pulmonary edema, convulsions and brain damage.
Acute aflatoxicosis in humans is relatively rare, but the more chronic, lower-level exposure is probably more prevalent than reports would suggest because the symptoms are difficult to recognize. Chronic exposure is a significant concern due to its insidious nature and potential long-term effects, which include immunosuppression, cirrhosis, and liver cancer. There are at least 13 different species of mold that produce 20 different aflatoxins, with aflatoxin B1 considered the most toxic. Aflatoxins affect nearly every system of the body, as the following list shows.
Respiratory: Pulmonary edema, cancer
Cardiovascular: Heart inflammation
Neurological: Reduced oxygen flow, headache, neuron death, encephalopathy, impaired memory, insomnia, disorientation, loss of coordination; tumors in both central and peripheral nervous system
Gastrointestinal: Liver damage, liver cancer, vital hepatitis, parasite infestation
Urinary: Kidney damage and tumors
Reproductive and Developmental: infertility, teratogenic, abnormal growth and development in children
Endocrine: Tumors and cancer
Blood: Blood and bone cancers
Immune: Immunosuppression, autoimmune reactions and allergies
Other: Mitochondrial malfunction, interference with protein and RNA synthesis, apoptosis (cell death).
Aflatoxins Are Everywhere
Aflatoxins are poisonous compounds produced by certain strains of the fungi Aspergillus flavus and A. parasiticus, which grow when temperature and humidity conditions are favorable. The highest levels are typically found in foods from warmer regions with greater climatic variation. However, aflatoxin-producing molds show an affinity for multiple types of crops and can grow under a broad-range of moisture and temperature conditions.
The permitted level of aflatoxin in groundnut for human consumption, according to international standards, is 4 parts per billion (ppb) in the European Union and 20 ppb in the US.
India, being second-largest producer of groundnut, faces difficulties in accessing these markets as the level of aflatoxin on Indian groundnut is high and is considered unfit for human consumption. In accordance with Agmark standards, the permitted level of aflatoxin in India is 30ppb.
Owing to high food safety and animal and plant health concerns, many SPS (sanitary and phyto-sanitary) notifications have been issued against India by several countries over the last few years. This has resulted in exports of groundnut oil to many developed and developing countries shrinking.
Effective solutions
India has now developed agricultural practices and technologies which can reduce the extent of aflatoxin to permitted levels.
Mere adoption of good varieties and good agricultural practices (GAPs) can help reduce the level of aflatoxin to 20 ppb. Breeding efforts have focused on reducing groundnut maturity periods to escape end-of-season drought, and the emphasis has been on the identification of short-duration farmer preferred lines with resistance to or tolerance of Aspergillus.
Among the recommended practice at production stage, applications of lime alone can reduce aflatoxin contamination by 72 per cent, while application of farm yard manure reduces aflatoxins by 42 per cent under field conditions. When combined, aflatoxin contamination can be reduced by up to 84 per cent. Harvesting at appropriate stage, adoption of proper drying method, reducing kernel moisture to the level of 8 per cent, etc prevents the accumulation of aflatoxin significantly.
The Directorate of Groundnut (Junagarh) recommends some of the measures such as crop rotation with onion or garlic, selection of short- and medium-term varieties, advanced sowing, supplemental irrigation during end of the season, etc to reduce aflatoxin.
