DETECTION OF MUTAGENICITY IN SOME ORIENTAL NATURAL SEASONINGS BY FORWARD MUTATION ASSAY

Upon establishment of optimum analytical conditions for the forward mu tation assay, various types of soy sauces manufactured in China, Korea and Japan (37 samples) and Japanese natural extracts (9 samples) were measured for their mutagenicity with the following results: (i) accur ate determination on histidine-rich samples could not be carried out b y the standard Ames's preincubation method; (ii) most of the mutagenic activities in soy sauces were eliminated by treatments for removal of free histidine using Blue rayon or Extrelut column; (iii) no interfer ence with histidine on mutagenicity determination of histidine-rich sa mples was observed when measured by the forward mutation assay propose d originally by Skopek et al (Proc Nat Acad Sci USA 75 (1978) 410-414) using Salmonella typhimurium TM677, when correction was employed for the loss of colonies by high salinity samples; (iv) mutagenicity was f ound in all soy sauces (+S9, 26-72 (average 46) mutants mg(-1); -S9, 5 1-111 (average 81) mutants mg(-1)) and half of the natural extracts te sted (+S9, 1350-1450 (average 1400) mutants mg(-1), -S9, 1150-2650 (av erage 1693) mutants mg(-1)) by the forward mutation assay. The structu res, origins and variability of mutagenic compounds during the manufac turing process would require further study.