腐敗細菌としてのGenus Serratiaの研究

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This paper deals with an analytical investigation on the significance of genus Serratia as the bacteria causing spoilage of foods. The results obtained are summarized as follows : 1). The distribution of Serratia spp. in foods and in their environment was investigated. Both nutrient agar and Bunting's Medium were used as isolation media. The author could isolate only 21 strains from 1000 samples of soil, water and fish meats. It shows that Serratia are narrowly distributed in nature and sparsely populated in food materials. 27 strains of this genus were used further experiments, 21 were newly isolates, 7 were laboratorium ones. 2). The cultural charactristics of all isolates were tested in detail. Though the strains were tried to classify into species by the fermentation of glucose, Voges-Proskauer Test and the growth temperature according to the key of the Berge's Manual(1948), they were indistinguishable from Serratia marcescens for their variability. So the author identified all of them Serratia marcescens. 3). Single inoculation test on various food materials. Animal Food: Bacterial growth was quite well in protein food and the substrate became alkalin rapidly. In every kind of animal foods, Serratia attacked protein materials and gave a putrefactive odor, changes in color and toughness to them. It was recognized that the activity against protein was common in Serratia. 4). Proteolytic activity of Serratia. Proteolytic activity was tested by means of the measurement of the quantity of NH_3-N which was produced in fish meat by inoculated bacteria. The large amount of NH_3-N was produced in each case and there was no difference among the strains. 5). Pigment production of Serratia on food. When Serratia multiplied on fresh food materials, they produced pigment abundantly, and the tone of color was red to pink. Many strains lusted their ability of pigment production recovered their activity in fish meat extract of fish itself. 6). Thermal death point of Serratia. All tested strains were killed when exposed to temperature of 70℃, 5 minutes. It shows that there was no strain to resist any pasteurisation process. 7). NaCl Resistance. Growth was inhibited in . medium containing 10 % NaC1 in tested strains. 8). Suger Resistance. There was some strains which have multiplied in medium contanining 60 % sugar. 9). Sensitivity against chemical agents. Antibiotics: Most strains were highly resistant to antibiotics, such as penicillin, aureomycin, terramycin, chloramphenicol and ilotycin. But 8 strains of them were very sensitive against streptomycin. They were inhibited their growth at the concentration of 1γ/cc of streptomycin. Preservatives: All strains were relatively resistant against some preservatives such as dehydroecetic acid and nitrofurazon.
千葉大学の論文
1955-09-28

腐敗細菌としてのGenus Serratiaの研究

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