Aflatoxin contamination in groundnut induced by aspergillus flavus type fungi: A critical review.

Groundnut (Arachis hypogaea L.) is an annual legume which is also known as peanut, earthnut, monkeynut and goobers. It is the 13 th most important food crop and 4 th most important oilseed crop of the world. Groundnut seeds are a nutritional source of vitamin E, niacin, falacin, calcium, phosphorus, magnesium, zinc, iron, riboflavin, thiamine and potassium. Groundnut kernels are consumed directly as raw, roasted or boiled kernels or oil extracted from the kernel is used as culinary oil. It is also used as animal feed (oil pressings, seeds, green material and straw) and industrial raw material (oil cakes and fertilizer). These multiple uses of groundnut plant make it an excellent cash crop for domestic markets as well as for foreign trade in several developing and developed countries. The crop is affected by several diseases like leaf spots, collar rot, rust, bud necrosis, stem necrosis etc. Apart from these, aflatoxin is one of the major problems, produced in the infected peanut seeds by Aspergillus flavus Link ex fries and Aspergillus parasiticus Speare, particularly at the end of season under drought conditions (Diener et al., 1987). Aflatoxins are highly carcinogenic, immunosuppressive agents, highly toxic and fatal to humans and animals particularly affecting liver and digestive track. Aflatoxin is a potent human carcinogen. It is a naturally occurring toxic metabolite produced by certain fungi (Aspergillus flavus), a mold found on food products such as corn and peanuts, peanut butter. It acts as a potent liver carcinogen in rodents (and, presumably, humans). They are probably the best known and most intensively researched mycotoxins in the world. Aflatoxins have been associated with various diseases, such as aflatoxicosis, in livestock, domestic animals and humans throughout the world. In the present chapter, a detailed account on groundnut aflatoxins induced by A. flavus group of fungi was presented. ECONOMIC IMPORTANCE OF AFLATOXINS A variety of contaminants are found naturally occurring in foods. Of these, mycotoxins are the major contaminants and 25 percent of foods are contaminated with mycotoxins. Among them aflatoxins are the major mycotoxins produced by toxigenic strains of A. flavus and A. parasiticus in the suitable environment. Aflatoxins are the secondary metabolites produced by these fungi. Aflatoxins cause economic and trade problems at almost every stage of marketing of groundnut especially during export. Earlier reports indicated that over a decade, the export of groundnut productions from India has declined from 550 metric tons (valued at US$ 42.5 million) to 265 metric tons (valued at US$32.5 million) due to the presence of aflatoxins. Importing countries have prescribed the standards for groundnut. In India permissible level for aflatoxin in groundnut is 30ppb per kg. According to Indian council of medical research (ICMR), Lucknow, 21 % of groundnut and maize samples in India are unfit for human consumption due to aflatoxin contamination. In order to protect the international trade, in 29th meeting, codex committee on food additives and contaminants (CCFAC) a draft level of 15microgram per kg for total aflatoxin in peanuts intended for further processing was proposed as the maximum level. If this level is applied, 37 percent of our groundnut samples are rejected. In Andhra Pradesh groundnut samples contain 15-19 percent excess aflatoxin than the permissible level.