Team:CIEI-BJ/Background
Aflatoxin is toxic secondary metabolites produced by Aspergillus fungi and Aspergillus parasiticus. AFB1 is the most potent and potentially lethal metabolite and is a known human carcinogen. Aflatoxin are abundant in warm and humid regions, consequently contaminating crops at harvest and during storage. Once the crops were contaminated, the aflatoxin cannot be removed through normal process of cooking.
Aflatoxin are abundant especially in warm and humid regions. They can contaminate crops at harvest and during storage. Once the crops are contaminated, the aflatoxin in those crops can not be removed by cooking or degraded by our body.
Our everyday commodities such as corn, peanut, pistachio, coconut, soybean, rice etc. are all prone to aflatoxin contamination. Aflatoxin in those products will then be ingested by us after directly eaten. Since animal body cannot degrade aflatoxin, the aflatoxin in animals will be transferred to us if we consume any product from those animals.
Furthermore, ingesting small amount of aflatoxin not enough to cause aflatoxicosis would also bring life threatening risks for a long period of time. The consequence of chronic aflatoxin exposure will lead to a deadly disease, hepatocellular carcinoma (liver cancer). Pregnant woman who suffer from chronic aflatoxin exposure might pass on the toxic aflatoxin to their babies. These new born babies will suffer from stunted growth and immune suppression.
A causative role in 4.6–28.2% of all global HCC cases
Toxicity of aflatoxin mainly targets our liver, causing substantial damage to the liver. Ingesting large amount of aflatoxin will lead to aflatoxin poisoning called aflatoxicosis, and the case fatality rate of aflatoxicosis is 25%. Related symptoms could be: vomiting, abdominal pain, pulmonary edema, convulsions and coma. Severe aflatoxicosis might lead to death with cerebral edema and fatty involvement of the liver, kidneys and heart. It was estimated that approximately 10 to 20 mg of aflatoxin will kill an adult.
Aflatoxin are slowly affecting people from all around the world, especially developing and underdeveloped countries which haven’t enforce regulations on aflatoxin in crops due to financial reasons.
In 2004, the aflatoxicosis outbreak in Kenya was one of the most severe episodes of human aflatoxin poisoning in history. Total cases reported was 317 and the fatality rate was 39%.
However, chronic exposure to aflatoxin might bring risks to people on a larger scale. Over 55 billion people worldwide are at risk of uncontrolled exposure to aflatoxin.
Of the 550,000–600,000 new HCC cases worldwide each year, about 25,200–155,000 may be attributable to aflatoxin exposure.
Therefore，there is an urge for a biological method to detect and degrade aflatoxin. Our team’s project aims for a detection and degradation system for aflatoxin with minimum impact to food. It can protect people from exposure to aflatoxin and also reduce waste of agricultural products.