have examined shoyu, miso and mirin for pyrazine compounds. On prolonged cultivation, 26 of 68 industrial Aspergillus
strains produced aspergillic acid, but if incubation was restricted to only 2 or 3 days, then contamination with this material could be avoided. They point out that some strains produce it earlier than do others, and suggest that the
latter be used for food production. They also adduse evidence that ether extracts of shoyu at dose rates corresponding to a year’s consumption of shoyu by a Japanese adult (12L of shoyu) were not lethal to mice upon intraperitoneal injection.