1. Introduction
Aflatoxin contamination of peanuts results from growth in peanut
kernels by toxigenic strains of Aspergillus flavus and Aspergillus
parasiticus. Soil is the main source of inoculumfor A. flavus/A. parasiticus
and as peanut fruits develop underground, pods are in direct contact
with the soil fungal populations (Horn and Dorner, 1998).
Pre-harvest aflatoxin contamination of peanuts is associated with
severe late-season drought stress. Contamination can also occur after
peanuts are dug if they are not quickly harvested, dried and maintained
at safe moisture level; or during storage when improper conditions of
moisture and temperature exist (Cole et al., 1995). Lots of peanuts
with excessive levels of contamination cannot be used for human consumption
and therefore represent great economic losses for the peanut
industry (Lamb and Sternitzke, 2001).
Aflatoxins are carcinogens and genotoxins that directly alter theDNA
structure (Williams et al., 2004). Government regulatory agencies have
established very low tolerances for aflatoxins in food, including peanuts
and peanut products. The upper limit for aflatoxins in peanuts is 2 ng/g
for aflatoxin B1 and 4 ng/g for total aflatoxins (B1 + B2 + G1 + G2) in the
European Union and 20 ng/g for total aflatoxins in the United States