Sterigmatocystin and aflatoxin B1 contamination of corn, soybean meal, and formula feed in Japan

Sterigmatocystin (STC) and aflatoxin B 1 (AFB 1 ) were analyzed in 246 corn samples, 126 soybean meal samples, and 861 formula feed samples from the Japanese market between April 2010 and March 2015. The detection rate, the highest concentration, and the mean concentration of STC were respectively 14%, 6.4 μg/kg, and 1.2 μg/kg for corn; 14%, 1.1 μg/kg, and 0.63 μg/kg for soybean meal; and 43%, 9.1 μg/kg, and 0.97 μg/kg for formula feed. The detection rate, the highest concentration, and the mean concentration of AFB 1 were respectively 46%, 24 μg/kg, and 3.9 μg/kg for corn; 30%, 6.7 μg/kg, and 1.1 μg/kg for soybean meal; and 47%, 20 μg/kg, and 1.6 μg/kg for formula feed. A weak negative correlation between the STC and AFB 1 concentrations was observed: there was a high concentration of AFB 1 in samples that contained a lower concentration of STC and vice versa. Spearman’s rank correlation coefficient showed a weak negative correlation of − 0.30 ( p