INVESTIGATION O N SPOILAGE OF WINTER HERRING
57Watson (1939) likewise was interested in the trimethylamine oxidereducing bacteria, and studied for this purpose chiefly members of the genus Achromobacter which, according to his findings, is chiefly responsible for the spoilage of cod muscle a t low temperatures. Some 200 species of facultative anaerobes were studied in cod muscle press juice, besides aerobic types belonging to the genera E'lavobacterium and Achromobacter. He concludes that the reduction of trimethylamine oxide is not a function of the bacterial population since only certain types of bacteria are capable of reducing trimethylamine oxide. He also found that obligate anaerobes are of no importance in the initial stages of fish spoilage.Literature concerning chemical and bacteriological changes in fish muscle during storage is well reviewed by Notevarp, Hjorth-Hansen, and Karlsen (1942) and Hjorth-Hansen (1943). These investigators concerned themselves chiefly with the chemical side of these problems.Kimata (1942) made microbiological studies on the spoilage of "semidried fishes, " examining 181 cultures isolated from fish in decomposition. The organisms were, according to frequency of occurrence, Micrococcus, nonsporeforming, and sporeforming rods. The nonsporeforming organisms belonged to the genera Achromobacter, Plavobacterium, and Pseudomonas. The spoilage of the "semi-dried fishes" is attributed chiefly to the action of cocci and nonmotile rods, thus being different from the spoilage of fresh fish which is principally acted on by the nonsporeforming, motile, water bacteria belonging to Pseudomonas, Achromobacter, and Plavobacterium.Thjotta and Somme (1942) made an extensive bacteriological examination of 19 species of fish including sea fish as well as fresh-water fish taken from different localities in Norway. I n all 379 bacterial strains from the skin, gills, and intestines of freshly captured fish were classified according to Bergey (1939) and represented seven families and 16 genera.Aschehoug and Vesterhus (1943) made a study of the normal bacterial flora of freshly caught winter herring for the purpose of examining the distribution of the initial flora of the fish. This investigation, being the first phase of an extensive study of the bacterial flora of the same fish during storage, was carried out during two winter fishing seasons in order to obtain an average of the normal bacterial flora of fresh fish. According to their findings the fish flesh is sterile. From the slime, gills, and intestines 272 organisms were isolated, and their characteristics were studied in detail. There was no special qualitative difference in the flora from the various sources. The following five genera were represented in the slime and gills : Pseudomonas, Achromobacter, Plavobacterium, Micrococcibs, and Proteus. In the intestines only three of the mentioned genera, Achromobacter, Pseudomonas, and Micrococcus, were demonstrated. Of potential importance for the keeping quality of the fish was the demonstration o...
