1990 Volume 37 Issue 9 Pages 687-694
Bacterial spoilage of film-packaged kamaboko in cold storage was investigated microbiologically. The softening of tissue and the production of fluorescent pigments were observed in a spoiled portion of kamaboko. The causative bacteria was isolated from the spoiled kamaboko, and an isolated strain was identified as Pseudomonas fluorescens biovar V based on Bergey's manual of systematic bacteriology volume 1. The characteristics of P. fluorescens IFO 3081 and the isolated strain showed the following results.The G+C molar percentage of DNA in the isolated strain was 60.76%, which nearly coincides with 61.06% in P. fluorescens IFO 3081. The proteolytic activity of the isolated strain was positive, but that of P. fluorescens IFO 3081 was negative. The isolated strain could grow at -2°C but not at 38.5°C, and the optimum temperature for growth was from 30 to 31°C. Therefore, the isolated strain may be psychrotrophic bacteria, which coincides with the characteristics of facultative psychrophile. When the isolated strain was inoculated onto kamaboko, the softening and production of fluorescent were observed on its surface, but P. fluorescens IFO 3081 did not cause spoilage. From the results that the isolated strain and P. fluorescens IFO 3081 were different in proteolytic activity, it is supposed that bacterial proteases may play an important role for growth of the genus Pseudomonas on the surface of kamaboko.
