Distribution of Clostridium botulinum in soil, debris and water was examined in Toyama Prefecture for the purpose of preventing food poisoning due to this organism. The results obtained were as follows: Detection frequencies of C. botulinum from soil or debris decreased in the following order; pond (7/9, 78%), river (12/23, 52%), fishing port (2/20, 10%), rice field and vegetable garden (1/40, 2%). The toxin types detected were C₁ (9 samples), C₁+D (8), C₁+C₂ (2), C₁+C₂+D (2) and E (1). The main toxin in the cultures containing C₁+C₂ or C₁+D was C₁. The level of C₁ toxin detected was the highest in pond among all cultures examined. C₁ toxin was detected in December, February, April and June, but not in August or October, in cultures of the pond where wild ducks were seen during the winter season.
These results indicate that the dominant type of C. botulinum distributed in Toyama Prefecture is C_a. This may be related wit the migration of wild ducks. Type D was less dominant and type E only rarely detected.

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Experiments were carried out to find the most adequate incubation temperature for growing Salmonella in a combination of pre-enrichment and some selective enrichment culture. The results are as follows: Pre-enrichment for 18 h in EEM medium at 42°C as followed by growing for 20 h at 35°C in selective enrichment medium was most an efficient to isolate Salmonella from various meats (method III). In addition to method III, adoption of method II consisting of pre-enrichment for 18 h at 35°C and then growing for 20 h at 42°C in a selective medium further increased the rate of detection of Salmonella in meats.

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Honey has served as a vehicle of Clostridium botulinum spores in infant botulism. The present study was designed to find the stability of the spores in honey during storage at different temperatures. When honey samples containing 10⁴/g of type A (62A) or type B (Okra) spores were stored at 4°C, the spore population did not change over a year. At 25°C, however, the spores decreased in number gradually after 100 days. Only 1% of type A and none of type B spores were detected after 400 days of storage. None of such physico-chemical treatments as heat shock, sonication and treatment with detergent, enzyme, alcohol, acid and alkaline had significant effect on the botulinum spore population. Neither type A nor type B spores were detected after 5 days of storage at 65°C. Type B seemed to be more sensitive than type A spores. At this temperature, the honey deteriorated slightly in terms of hydroxymethyl furfural and diastase number. It is not known whether the decrease in the spore count was due to the death or failure in germination of the spores. At any rate, a long-term storage at 25°C or mild heating at 65°C for about 5 days may eliminate or at least to reduce C. botulinum spores in honey.

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A total of 171 soil samples were collected from coasts, inlets, ponds, marshes and artificial pond in Miyazaki Prefecture to survey for Clostridium botulinum from April, 1987 to September, 1988. Botulinum toxin was detected in enrichment cultures of 18 (10.5%) out of 171 soil samples. These toxins were identified by the neutralization technique; two were type C₂ and the other 16 were neutralized equally with either monovalent anti-toxin type C₁ or D.

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食品からのサルモネラ検出用に開発されたEquateキットの実用性を検討した結果, 以下の成績が得られた.
1. 血清型の異なるサルモネラ61株のうち60株はELISA法による吸光度0.15以上となり陽性と判定された. 陰性と判定された1株は, 非運動性のS. typhimuriumであった.
2. S. typhimurium, S. infantisおよびS. enteritidisの各菌量と本キットによる反応性は, いずれの菌株も菌量10⁶個/ml以上で陽性を示した.
3. E. coli11株およびCitrobacter spp. 37株に対する本キットによる反応性は, すべての株が陰性を示した.
4. S. infantis, S. litchfieldおよびS. enteritidisの各菌量 (10, 10², 10³個) を食肉25g中に添加し, 本キットによる反応性を調べた結果, いずれの菌株も10個のオーダーの添加により陽性を示した.
5. 市販食肉120検体について, 本ELISA法と従来の検査法による, サルモネラ検査を実施した結果, 両法とも陽性を示したものが17検体 (14.2%), ELISA法のみ陽性が13検体 (10.8%), 両法とも陰性のものが90検体 (75.0%) で, 両法による一致率は89.2%であった.

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Q-TROL is an enzyme immunoassay (EIA) kit for detecting Salmonella antigens in foods by use of monoclonal antibodies against Salmonella coated on wells of plastic trays. Q-TROL was compared with the conventional method for detecting Salmonella from the same meat samples in three laboratories by the same methods. A preliminary study was performed to improve the original method described in the manual for saving time and for simplifying the procedure. As the results, it was found that the incubation in M broth at 35°C for 6 h followed by enrichemnt culture in SBG at 43°C for 18 h could be omitted, and that SBG was most effective among various selective enrichment media. One hundred chicken meat samples were analysed by both the methods, conventional and EIA, in three laboratories (A, B and C), and other 94 samples of a variety of food in laboratory C. There was a good correlation in the samples positive by both the methods without any false negative, but there were a few false positives. The EIA screening method has been regarded as a rapid and reliable method for detecting Salmonella.

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こんにゃくを軟化剥離し, 溶解を起こす原因菌について検索した結果, こんにゃく26件中9件, しらたきの浸漬液1件中1件よりJ-agar培地上で同一集落形状を示すグラム陽性のやや湾曲した無芽胞小桿菌を分離した. 本菌は, 鞭毛はなく非運動性で, カタラーゼ陽性, 熱に対する抵抗性はなく, 65℃10分の加熱で死滅した. 以上により, 溶解菌はこれまでに知られていたBacillus属ではなく, coryneform bacteriaに属するものと推定された.
分離菌株を滅菌こんにゃくに接種し, 30℃で培養したところ, 培養3日頃から菌発育部位にこんにゃく溶解が観察された.
本菌の発育温度域は12～39℃, 至適発育温度は27～32℃, 発育pH域はpH6.5～10.0, 至適発育pHはpH7.5～8.5であった.
また分離菌をJ-broth (pH7.3) に接種して3日間振盪培養を行った後, この培養上清に滅菌こんにゃくを入れ30℃に保存した場合, 約2時間でこんにゃくの表面に剥離が始まり, 6時間後には完全に溶解した. 以上の結果から培養上清にはこんにゃくを溶解する酵素が産生されているものと推察された.

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SDS-polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell preparations of Campylobacter species were performed to find whether the profiles obtained by silver staining could be used for the rapid identification and differentiation among species of Campylobacter.
The profiles of C. jejuni, C. coli, C. laridis and C. fetus subsp. fetus could be distinguished from one another on the basis of migration of the major bands. A major band at the position of approximately 80, 000 daltons was observed as the distinctive band of C. jejuni, and two major bands at the positions close to 80, 000 daltons were characteristic of C. coli.
This method could be completed within 5 hr by use of ready-made gel and silver staining.

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The main cause of Campylobacter jejuni contamination of chicken meat is thought to be leakage of feces containing C. jejuni from the vent or cross-contamination by treating with the same implements such as the chopping board, cutlery cloth and so on, during the dressing processes by the “sotomuki” (evisceration after cutting the carcass into the front and back halves) or “nakanuki” (evisceration without cutting up the carcass) method used in Japan. Improved steps which could reduce C. jejuni contamination of chicken meat are as follows: for “sotomuki”; i) closing the vent so as to avoid leakage of feces, ii) soaking the carcass in a 1-2 ppm NaClO solution for 15 min, iii) removing the internal organs on another chopping board by use of clean cloth, and for “nakanuki”, setting up or icreasing the washing steps at five points.

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Listeria monocytogenesについて至適pHと各温度における世代時間を測定し, 次のような成績が得られた.
1) pHを5.5～8.5に調整したBHIで振盪培養し, 分光光度計によって測定したOD値で得られた増殖曲線から至適pHを調べた結果, pH7.0にあることが知られた.
2) 本菌を接種したBHIを4～35℃でジャー・ファーメンターを用いて好気的に培養して世代時間を測定した結果, 4℃では16.8時間, 10℃では270分, 15℃では138分, 20℃では72分, 25℃では57分, 30℃では44分, 35℃では33分であった.
3) 微好気的条件として混合ガス (酸素: 二酸化炭素: 窒素=4.9: 9.9: 85.2) を通じて培養した場合には, 4℃では15.6時間, 10℃では342分, 15℃では150分, 20℃では96分, 25℃では58.5分, 30℃では39分, 35℃では32分という値が得られた.
4) 得られた世代時間からQ₁₀値の算出を試みたところ, 好気的条件下では, 20℃を中心にして (1.6前後) 培養温度の上昇あるいは減少に伴って値は上昇した (1.78～3.84). 微好気的では概して培養温度の減少とともに値は上昇した(1.49～5.22).

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