VIABILITY AND HISTIDINE-DECARBOXYLASE ACTIVITY OF HALOPHILIC HISTAMINE-FORMING BACTERIA DURING FROZEN STORAGE

The specific activity of histidine-decarboxylase of halophilic histami ne-forming bacteria, Photobacterium phosphoreum and Photobacterium his taminum sp. nov., remained 27 approximately 53% of the initial value a fter seven days storage at -20-degrees-C, while the viable cells decre ased by more than 6 log cycles of the initial counts. This finding sug gests the possibility that outbreaks of scombroid fish poisoning are c aused by the ingestion of frozen-thawed fish and its products, even wh en the viable count of histamine-forming bacteria is low.