Changes in moisture content, mycoflora and aflatoxin content of rice bran during storage

The changes in moisture content, storage mycoflora and aflatoxin B1 (AFB1) in bran from untreated or raw rice (Rr) and parboiled rice (Pbr) stored in small lots in polyethylene bags were studied at 15-day intervals up to 60 days, using five lots of each type of bran. Deterioration was more rapid with reference to all the three parameters, in Rr bran compared to Pbr bran, the former becoming completely overgrown and caked with fungi by the end of 60 days. Aspergillus flavus was the dominant fungus in Pbr bran, whereas A. candidus and Trichoderma viride were abundant in Rr bran. The frequency of incidence as well as concentration of AFB1 increased with storage time in both types of bran, but the rate of increase as well as overall concentration were much higher in Rr bran. Thus raw rice bran is unsuitable for prolonged storage.