Mycotoxin contamination and presence of mycobiota in rice sold for human consumption in China

Abstract

In China, aflatoxin B1 (AFB1) and sterigmatocystin (STC) have been detected in rice but there is no published information on the mycobiota in toxin-contaminated rice samples. Occurrence of AFB1 and STC was evaluated in 100 rice samples. Out of 78 samples of polished rice, 12 and 23 samples had detectable levels of AFB1 and STC, respectively, at mean levels of 0.14 μg/kg and 0.39 μg/kg, respectively. The highest level of STC in polished rice was 2.76 μg/kg in a sample from Hubei province; out of 22 samples of unhusked rice, STC was detected in 12 samples at a mean level of 0.91 μg/kg; however, only one sample contained detectable amounts of AFB1 at a level of 0.2 μg/kg. Seven samples that were positive for both AFB1 and STC were selected and evaluated for the presence of mycobiota; species of Aspergillus and Penicillium predominated. Twelve species of Penicillium and fifteen species of Aspergillus were isolated, of which P. fellutanum and A. candidus were the most frequently found. Further studies are now required to determine which of these species produce AFB1 and STC.