Abstract
In the previous paper, it was shown that the bacterial flora in the spoilage of chilled raw fish mainly consisted of members of the Pseudomonas III/IV-H, III/IV-NH and the Vibrio group.
The present study was undertaken to investigate bacterial flora of frozen fish and the spoiled fish after thawing and storing at chill temperature.
For enumeration and isolation of bacteria the smear plate method was employed using 50% sea water agar medium described in the previous paper. From the skin of the five frozen fish samples 74 strains were isolated, while 75 strains were obtained from the skin and muscle of the spoiled fish samples, respectively. The majority of isolates from the skin of frozen fish consisted of the Moraxella, the coccal groups and the other undetermined group, and the Pseudomonas and the Vibrio, which were dominant on the fresh raw fish as reported in the previous paper, formed only a small proportion of the isolates in the case of the frozen fish. After spoilage, on the other hand, the Pseudomonas III/IV-H, II and I, which were absent before storage, appeared markedly, and they accounted for most proportion of the isolates together with the Moraxella, while the above-mentioned coccal groups and the undetermined group disapeared. The Pseudomonas III/IV-NH and the Vibrio, which are most important spoilage bacteria of raw fish, were isolated in a small number from the spoiled fish in the present work.
