スモークサーモンの原材料の凍結紅サケおよび最終製品を対象にリステリア属菌の汚染調査を行った. その結果, 調査した凍結紅サケ60例のすべてが陰性であったが, 製品では76例中23例 (30.3%) が陽性であった. 陽性例の12例からL. monocytogenesが検出され, このほかL. welshimeri, L. innocua, L. seeligeriが認められた. 分離されたL. monocytogenesの血清型は1/2a, 1/2b, 1/2c, 3a, 3b, 4bの6型に型別された.
実験的に1g当たり10²レベルにL. monocytogenesを接種したスモークサーモンを好気または嫌気包装して2および10℃に保存したところ, 好気包装では2℃保存で10日目に10⁴～10⁵レベル, 20日目には10⁸レベルとなり, 10℃保存で5日目に10⁷～10⁸レベルに達した. 嫌気包装では好気包装と比較して若干発育が抑制される傾向が認められた. 原材料サケおよび最終製品のスモークサーモンを-20℃で保存した場合は, 実験的に接種した10⁴～10⁵レベルのL. monocytogenesはいずれも6カ月後も1オーダ程度の菌数減少にとどまった.

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Production of a factor causing vacuoles in HEp-2 culture cells by Bacillus cereus No. 55 was examined in a semi-synthetic medium containing ammonium sulfate as a sole nitrogen source (AYPS medium). Although the vacuolation activity in the culture supernatant was low after cultivation of B. cereus in the medium, the activity was increased by supplementation of glucose to the medium. However, the activity did not increase by the supplement of galactose and lactose to the medium.
The activity of the factor increased with an increase in the cell concentration of B. cereus when it was cultured with shaking in AYPS medium supplemented with 0.5% glucose. In the medium with 0.1% glucose, the cell concentration reached the highest level at 8 hr, but the activity was the highest at 48 hr. In both media the rate of sporulation was above 65% after a 48hr cultivation with shaking. By contrast, the rate of sporulation was very low (4-15%) without shaking. The activity was first detected at 24 hr and increased until 48 hr to the same level as that in the culture with shaking.
For purification of the vacuolation factor, salting out with ammonium sulfate, n-butanol extraction, solubilization with methanol and thin-layer chromatography (TLC) on silicagel 60 were effective. After fractionation by the TLC, the vacuolation activity was detected in five fractions.

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ラクチュロース (3g/日, 2週間), または乳果オリゴ糖 (2g/日, 1週間) を摂取させた各9人の健康成人の糞便内レシチナーゼ陽性Clostridiumの菌種, 検出率と菌数を測定した結果, ラクチュロースまたは乳果オリゴ糖摂取前にはそれぞれ9例中9例 (平均3.9×10⁵/g) と9例中8例 (4.5×10⁵/g) から本菌が検出されたが, ラクチュロースまたは乳果オリゴ糖摂取後はそれぞれ9例中4例 (4.2×10³/g) と9例中6例 (2.9×10⁴/g) と減少傾向を示した. なお, レシチナーゼ陽性Clostridiumの菌種としてはオリゴ糖摂取前でClostridium perfringbens (10²～10⁸/g) が18例中17例, C. sordellii (10³～10⁵/g) とC. baratii (10²/g) が各2例, C. bifermentans (10³/g) が1例から検出されたが, ラクチュロースと乳果オリゴ糖摂取ではC. perfringbensのみがそれぞれ9例中4例 (10²～10⁵/g) と9例中6例 (10²～10⁷/g) 検出された.

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The microflora and metabolic products between the cecum and feces of rats were compared. The microflora of the cecum was similar to that of the feces. However the metabolic products greatly differed between the cecum contents and feces. The pH value was higher and the amounts of short-chain fatty acids (SCFA) and ammonia were larger in the cecum contents than in the feces. Particularly concerning the SCFA, the level of acetic acid, propionic acid and butyric acid were significantly higher in the cecum contents, and the latter were not found in the feces.

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The effects of Lactobacillus isolated from funazushi (salted and fermented crusian carp) on the fecal microflora and metabolic products were studied in rats.
Mixed cultures containing the following viable cell levels per day of Lactobacillus were administered in rats: L. alimentarius, 10⁸; L. plantarum, 10¹⁰; L. sake, 10¹⁰; L. sanfrancisco, 10¹⁰; and L. kefir, 10¹⁰. On days 7 and 14 of lactobacilli administration, the number of fecal Lactobacillus tended to increase, while Enterobacteriaceae and Staphylococcus significantly decreased (p<0.05). The concentration of fecal ammonia and short-chain fatty acids, and the fecal pH values did not change markedly during lactobacilli administration. The amount of daily fecal evacuation significantly increased (p<0.05) during the test period.

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The antimicrobial activity of mustard extract, which has allyl isothiocyanate as the major pungent component, against Escherichia coli, Vibrio parahaemolyticus, Salmonella Typhimurium and Staphylococcus aureus, typical food poisoning bacteria in Japan, was examined by gaseous contact.
The mustard extract preparation and each nutrient agar plate spread with the test bacteria were put in a lunch box made from polystyrene, which was then incubated at 30°C.
The vapor concentration of allyl isothiocyanate in the container rose to about 180 ppm after one hour and since gradually decreased to about 30 ppm after 24 hrs.
The growth of each bacteria was tested at 3, 6, 9 and 24 hrs after start of incubation by counting the number of colonies formed on each selective agar media with samples prepared from the nutrient agar with the aid of a stomacher.
A bacteriostatic effect was observed against E. coli, S. Typhimurium and S. aureus 9 hrs after start of incubation and a bactericidal effect was observed against V. parahaemolyticus.

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