Aflatoxins and its Impact
Aflatoxins are poisonous cancer causing chemicals which are born in soil, decaying vegetation, hay and grain. Improper storage of staple commodities such as cassava, chili peppers, corn, cotton seed, millet, peanuts, rice, sorghum, sunflower seeds, tree nuts, wheat, and a variety of spices is a major cause for the growth of aflatoxins. Aflatoxins enter the general food supply through the contamination of aforementioned staple commodities. Animal food, human food as well as feedstock for agricultural animals gets contaminated. Aspergillus flavus and Aspergillus parasiticus are the molds which produce Alfatoxins.
Types of Aflatoxins –As many as 14 different aflatoxins are produced in nature.
- Aflatoxin B1 and B2 – Both are produced by both Aspergillus flavus and Aspergillus parasiticus. B1 is the most toxic aflatoxin.
- Aflatoxin G1 and G2- They are also produced by both Aspergillus flavus and Aspergillus parasiticus
- Aflatoxin M1 and M2 – M1 is a metabolite of the very poisonous aflatoxin B1. Adolescents get exposed to M1 from mother’s milk. M1 is found to be present in fermentation broth of Aspergillus parasiticus. M2 is a metabolite of B2. Both M1 and M2 are when a liver metabolizes alfatoxins B1 and B2.
How to detect the levels of aflatoxins in humans?
Aflatoxins are classified as compounds carcinogenic to humans.
- The presence of AFB1 –guanine adduct in urine indicates exposure too aflatoxin B1 during past 24 hours. This technique only measures recent exposure and hence AFB1 guanine level measure may vary from day to day and hence is not ideal for measuring long term exposure.
- Second method is measuring the AFB1-albumin adduct level in the blood serum. This approach provides a more integrated measure of exposure over several weeks or months.
Harmful effects of aflatoxins –
- High (acute) levels of contamination (above 200 ppb)
- Direct outbreak of human disease e.g. Aflatoxicosis in Kenya, 265 people died
- Acute illness and death, usually through liver cirrhosis
- Low (chronic) levels of contamination
- Child stunting and underweight (Togo, Benin – Gong et al, 2004 and Tanzania
- Immune suppression (The Gambia-Turner et al. 2003
- Acute and chronic contamination
- Liver cancer- 25,200 – 155,000 cases of liver cancer are attributable to Aflatoxins. This is up to 28.2% of all global liver cancers
Aflatoxicosis is a disease which occurs due to repeated exposure to aflatoxins. It affects growing poultry such as young pigs, calves, dogs et cetera. Adult cattle, sheep, and goats are relatively resistant to the acute form of the disease but are susceptible if toxic diets are fed over long periods. All species of animals have been experimentally found to be susceptible to exposure of aflatoxins. Exposure to aflatoxins is also visible in excreted milk and meat of animals which is harmful to adolescent humans.
Aflatoxins form on major component of aflatoxins. In the 1960s, about 100,000 turkey poults died near London, England due to peanut meal that was contaminated by Mycotoxins produced by Aspergillus flavus.
Outbreaks due to aflatoxins –
- 2003 Kenya : This was a case of acute poisoning due to aflatoxins which resulted in 120 deaths.
- February–March 2013: Romania, Serbia, Croatia and western Europe
- February 2013: Iowa contamination
- 2014 (ongoing): Population of Nepal and Bangladesh is suffering from neonatal exposures.
The problem of aflatoxins is serious as it has the potential to hugely affect the food cycle.
Aflatoxins in India –
In a country like India where almost 40% of population lives below the poverty line the problem of aflatoxins is a topic of concern. Also, the tropical nature of our geography where moisture and high temperature, season flash floods prevail simultaneously which leads to fungal proliferation and aflatoxin production. The major food crops in tropical regions are highly susceptible to contamination through aflatoxins. Not so good harvesting practices, improper storage and less than optimal conditions during transport also have a part to play in mycotoxin and hence aflatoxin contamination