魚函の細菌汚染に関する研究-I

Abstract

Generally, wooden fish containers are easily stained with bacteria in comparison with me-tallic fish containers. Therefore, the author investigated on the invasion of bacteria into the materials of fish containers. Takikawa's so-called pathogenic halophilic bacteria were employed as experimental organism, and the materials of wooden containers were used with chips of Japan ceder, pine and oak, because these are most using at fish markets. The experimental methods are shown in Fig. 1, and the results may be summerized as follows. 1. A marked difference was observed on the permeation of bacterial suspension into in-ner layer of chips according to the wooden qualities, roughness or fineness (see Fig. 2). 2. The materials which have been dried enough (moisture content; below 5%) were scarcely permeated into inner layer of wooden chips by bacterial suspension (see Fig. 3). 3. On the wet materials, were contaminated rapidly with bacteria (see Fig. 4 and Fig. 7). 4. It is noted that the resin-removed chips were easily stained by bacteria as compared with the unremoved (see Fig. 3 and Fig. 5). 5. On the wet materials which were dipped in 3% NaCl containing pepton medium, were seem to not only bacterial invasion into inner layer so rapidly, but also multiply in deep lay-er of wooden chips (shown in Fig. 7). From the above observations, when wooden fish containers are used repeatly at fish mar-kets, fishing vessels and cold storage factories, much attention should be paid for keeping cleanliness of wooden fish containers.