最近の変質魚肉ソーセージの細菌学的研究
1964 年 30 巻 2 号 p. 189-196
詳細
1964 年 30 巻 2 号 p. 189-196
Bacteriological studies have been conducted on the fish sausages deteriorated with the surface spoilage such as gassiness, softening of tissue and various types of spots. These types of spoilage have been often encountered when the fish sausages stored at higher than 30°C although they contain a high concentration of nitrofurazone.
The presence of large numbers of Gram positive bacteria was observed in the surface areas of gassy or softened sausages. The cores of the spots was found to consist of masses of Gram positive bacteria grown in the enmeshing structure of the tissue (Plate I, 1-5).
Most of the cultures isolated from the spoiled sausages classified into three distinct groups of genus Bacillus, i. e. B. coagulans, B. sphaericus and a species resembling morphologically and physiologically to B. firmus except for its anaerobic production of gas from nitrate, in-ability to hydrolyze starch and non-inhibitory growth to glucose media (Table 2 and 3).
The surface gassiness was confirmed to be due to the production of gas from nitrate by the denitrifying bacteria of the last group (Table 5 and 6, Plate I, 6-a). The bacteria of this group were also found to form spots as the result of localized growth. They also caused the softening of the sausage on its surface when large amount was inoculated (Plate I, 6-b). The members of B. coagulans as well as of B. sphaericus seemed to cause spots, and color shape of which being varied according to the materials and manufacturing conditions.
The cultures of all three groups were found to have a high resistance against several food preservatives such as nitrofurazone, AF-2 (2-Furyl-3-(5-nitro-2-furyl) acrylamide), potas-sium sorbate, sodium dehydroacetate. Tylosin inhibited the growth of the isolates of B. coagulans and the denitrifying bacilli at a concentration of 0.5 p.p.m., while the Tylosin did not inhibit the growth of the isolates of B. coagulans and the denitrifying bacilli at a con-centration of 0.5 p.p.m., while the Tylosin did not inhibit the growth of the isolates of B. sphaericus at a concentration of 10 p.p.m. (Table 4).
