くさやに関する研究-I

くさや汁の防腐効果について

抄録

“Kusaya”, a local dried fish of Izu Island, is produced by steeping fish in Kusaya brine. Kusaya brine contains many kinds of bacteria, some of which are spoilage bacteria. But the brine can be kept for long periods without microbial spoilage.
In order to elucidate the antiseptic effect of Kusaya brine, the bacteria in Kusaya brine were investigated. It had been suggested that there might be some kinds of special bacteria in the brine and these might keep the so-called “balance in micro-flora” constant. The balance was probably kept by the pH value and the salt concentration of Kusaya brine. The Kusaya brine used in this study was 8.5 in pH value and NaCl 6% in salt concentration. In fact, under these conditions the growth of bacteria clinging to fish-meat was inhibited to some extent.
Seven strains of special bacteria were isolated in Kusaya brine. Five of them were rod-strains (Gram-negative) and the others were spiral-strains (Gram-negative). Of the isolated strains, A-2 strain, S-l strain, and S-3 strain played an important role in controlling the pH value in Kusaya brine.
S-3 strain in “Old” Kusaya brine became about one-tenth the size of that in “New” brine.