Effect of Surrounding Factors on Nitrite Production by Bacteria Related to the Fermented Pickles

Abstract

This paper describes the effect of surrounding factors on the accumulation of nitrite produced by bacteria related the fermentation of pickles and their nitrate reductase activities. The strains belonging to Pseudomonas grew at 20-30°C and accumulated nitrite at 10-30°C favourably. The strains belonging to Enterobacter and Klebsiella grew at 30-40°C favourably and accumulated a large amount of nitrite in the same temperature range. The strains belonging to Pseudomonas grew and accumulated nitrite successfully without NaCl, but failed the growth and nitrite production under the conditions with above 4 % of NaCl. On the other hand, the strains belonging to Enterobacter and Klebsiella grew and accumulated nitrite even in the presence of 6% NaCl. Though the nitrate reductase activity of the strains belonging to Pseudomonas lowered dramatically with increasing NaCl concentration, the effect of NaCl concentration on those of the strains belonging to Enterobacter and Klebsiella was relativily small. Nitrate reductase was activated by malic and lactic acids. Therefore, it was supposed that malic acid contained in vegetables used for pickling contributed to the production of nitrite in the fermented pickles. The nitrate reductase of the strains belonging to Pseudomonas was also activated by fructose, and that of the strains belonging to Enterobacter and Klebsiella was remarkably activated by glucose and fructose.