魚類食品におけるボツリヌスE型菌の発育と毒素産生に関する研究-IV

魚肉エキスの発芽に及ぼす影響

抄録

In a previous paper²⁾, one of us reported that spores of C. botulinum type E germinated rapidly and completely in synthetic media consisting of various combinations of L-alanine and one of such carbon sources as glucose, lactate, and inosine in the presence of bicarbonate and that L-alanine could be replaced by several analogous amino acids. In this paper, we extend these findings to include various fish extracts and show that these germinative compounds play an important role in the spore germination in fish extract media.
Heated spores germinated rapidly and completely in the extracts of salmon and atka macherel and to a lesser extent in those of plaice, cod, and shrimp. The squid extract was relatively ineffective. The contents of the germinative compounds, such as glucose, lactate, inosine, and amino acids, including L-alanine and its analogues, were determined in each sample of fish extract and compared with the germination rates for the individual extracts. Furthermore, the concentration requirements for these compounds were determined; more than 5 mM lactate and inosine were required for maximum germination of heated spores in L-alanine plus lactate and in L-alanine plus inosine, respectively. A glucose concentration of 5 mM was, however, inadequate to support any appreciable germination of unheated spores in L-alanine plus glucose.
From these results, we conclude that the concentrations of these germinative compounds, in particular lactate and alanine or its analogues, influence the ability of fish extracts to support spore germination of C. botulinum type E.