46I-3 |
Mutagenicity evaluation of isolates from ozonated corn |
A. D. PRUDENTE and J. M. King. Department of Food Science, Louisiana State University Agricultural Center, 111 Food Science Bldg., Louisiana State University, Baton Rouge, LA 70803 Aflatoxins are known contaminants of food and feeds. Ozonation, a physical/chemical oxidation method, has been recently developed as decontamination procedure for aflatoxins in grains. This study aimed to determine the safety of ozonation to reduce aflatoxin hazards in corn. Clean and contaminated corns were treated with ozone (10-12 wt%) at a rate of 2L/min for 96hrs. Reaction products formation was evaluated through sequential fractionation. Extracts from aflatoxin-free and contaminated corns with and without ozonation were tested for mutagenicity in the Ames assay using TA98 and TA100 as tester strains. Evaluation of mutagenicity followed the two-fold rule. No isolates from dichloromethane, methanol, and acetone extraction showed mutagenicity against TA98 up to a concentration of 10,000 µg/plate. Similar result was obtained from hexane extracts up to a concentration of 5,000 µg/plate. An increase in mutagenicity was observed from extracts obtained after Pronase digestion followed by dichloromethane extraction. The numbers of revertants from extracts were higher than the natural revertants. The Pronase organic fractions did not show mutagenicity but exhibited antimutagenic activity. Dichloromethane extracts tested against TA100 showed increased level of revertants compared to natural revertants both for untreated clean and contaminated corns. Isolates from methanol extraction did not show mutagenicity. Isolates from acetone extraction showed lower number of revertants compared to natural revertants up to 5,000 µg/plate but increased when 10,000 µg/plate was used. Extracts from hexane fraction exhibited antimutagenic activity. The number of revertants decreased with increased concentrations of extracts. Mutagenic activity of organic extracts from contaminated corn increased after digestion compared to natural revertants. However, other organic extracts exhibited antimutagenic activities. These findings provide evidence of antimutagenic compounds in corn that interfered with the assay. These results suggested either that a new-fat soluble mutagen is being formed or that the ozonation process is destroying natural inhibitors of mutagenicity in corn.
Session 46I, Toxicology & Safety Evaluation
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