Natural occurrence of aflatoxin in green leafy vegetables

Natural occurrence of aflatoxin (AF) in agricultural soils, green leafy vegetables (GLVs) and persistence in processed foods was investigated, in total 33 soil samples and 81 GLVs which belonged to 9 groups collected from nine vegetable-growing regions were studied. Seventy percent of soils and 69.2% GLVs were contaminated with AF ranging from 0.0 to 88 ppb. Root samples frequently had higher concentration of AFB1 in comparison with shoot samples. Under greenhouse conditions all the tested plants were found to take up AF. From xylem and phloem sap experiments it was clear that AF was gaining entry into the plant system via water-conducting xylem tissue and was translocated to aerial plant parts, with subsequent entry into the phloem. Of the two cooking methods studied, pressure cooking of GLVs significantly reduced the AF level in comparison with ordinary boiling. (C) 2012 Elsevier Ltd. All rights reserved.