Destruction of aflatoxin in corn with sodium bisulfite

Abstract

The ability of sodium bisulfite to destroy aflatoxins B1 and B2 in naturally contaminated corn containing about 2,350 ppb of B1 and 450 ppb of B2 was investigated. Under certain conditions, complete destruction of aflatoxin B1 was achieved. Aflatoxin B2, on the other hand, was resistant to sodium bisulfite and never over about 50% was destroyed. Moisture, sodium bisulfite level, time, as well as temperature had significant effects on aflatoxin degradation. Moisture levels of over 50% (wet weight basis) had a strongly adverse effect on the aflatoxin-bisulfite reaction. The most effective treatment involved soaking whole-kernel corn in a 10% sodium bisulfite solution for 72 h, removing the solution and incubating the corn in sealed plastic bags at 50°C. Complete destruction of aflatoxin B1 was achieved by 21 d. Sodium bisulfite exhibited antimicrobial activity in corn comparable to that of propionic acid, indicating possible utility as an effective mold inhibitor in stored corn at up to 40% moisture. Feed consumption by young chickens was unaffected until feed containing over 20 g of sodium bisulfite/kg was presented.