Public Health Significance of Aflatoxin in Food Industry – A Review

Abstract

Aflatoxins are a group of related fungal secondary metabolites primarily produced by the fungi, Aspergillus flavus and Aspergillus parasiticus. Aspergillus flavus and Aspergillus parasiticus colonize a wide variety of food commodities including maize, oilseeds, spices, groundnuts, tree nuts, milk, peanut and dried fruits. However, production of aflatoxin by these fungi depends on drought stress, rainfall, suitability of crop genotype for its climate, insect damage, agricultural practices and postharvest conditions (storage, transportation and food processing). Four major aflatoxins produced naturally are known as aflatoxin B1, B2, G1 and G2. Aflatoxin is both a food safety and public health issue because of its toxicity. When it is consumed, it can exert toxicity by altering intestinal integrity or modulate the expression of cytokins which can result to stunted growth in children and/or immune suppression. In the liver, aflatoxin may be transformed by certain p450 enzyme to its DNA reactive form Aflatoxin-8-9-epoxide which binds to liver proteins and lead to their failure, resulting in acute aflatoxicosis or it may bind to DNA, contributing to aflatoxin induced hepatocellular carcinoma (liver cancer). In high doses, aflatoxin can lead to acute liver cirrhosis and death in both human and animals. Aflatoxin exposure is linked to increased risk of liver cancer, immunesuppression, increased susceptibility to diseases such as HIV and malaria and possible compromised vaccine efficacy. Aflatoxin accumulation can be managed by primary interventions involving improved irrigation, use of fungicides, pesticides and insecticides, use of cereal strains resistant to fungal colonization, biocontrol by introduction of competitive non-aflatoxigenic strains of A. flavus and genetically modified crops that inhibit fungal colonization and improved storage conditions. Intervention strategies also encompass chemoprevention, using compounds that interfere with the absorption or metabolism of aflatoxins once ingested.