A mold strain (NCI 3168) isolated from spoiled brandy cake containing 1.7% ethanol was identified as Moniliella suaveolens var. nigra morphologically and physiologically. The assimilation of ethanol by this isolate and its growth in the 2% yeast extract and 1% malt extract plus 15% sucrose (YES) broth containing 0.5-15% ethanol were investigated. This isolate assimilated ethanol and grew better in the YES broth containing 0.5-5.0% ethanol than in the medium without it and grew even in the 10%-ethanol-containing YES broth at room temperature. Moreover, the residue of ethanol in the ethanol-containing (0-10%) medium in which the isolate was growing was determined by gas chromatography. This isolate was fermentative and produced 3-6% ethanol in the ethanol-containing (0-10%) YES broth at 4-10 days after inoculation, and then consumed most of the ethanol with in 3 weeks.
The polymerase chain reaction (PCR)-based detection methods of Clostridium perfringens enterotoxin (CPE) gene (cpe) from food and environmental samples and DNA fingerprinting methods for molecular epidemiologic analysis, i.e., restriction fragment length polymorphism analysis of PCR-amplified cpe regions (PCR-RFLP) and random amplified polymorphic DNA (RAPD), were investigated. We newly designed four primer regions within a cpe gene, and then developed two PCR amplification systems, CP-5' and CP-89. Both systems generated the expected sizes of amplicons, 957-bp and 207-bp, respectively from CPE-positive C.perfringensstrains. A nested PCR method, consisting of the first PCR by the CP-1 system, which we previously established, followed by a second PCR by the CP-89 system, could detect differences at a 100 level per reaction tube. To evaluate the usefulness of these PCR systems, we applied those to foods in a C.perfringensoutbreak, from which CPE-positive C.perfringenswas isolated by an enrichment culture procedure, and environmental samples such as those in soil and river sediment. The nested PCR method detected cpe genes in three of the four tested foods without enrichment. The CP-89 system combined with enrichment with TGC medium (TGC-PCR) detected cpe genes from 37 (77%) of 48 environmental samples, suggesting a higher level of distribution of this pathogen than that previously considered . For PCR-RFLP analysis of the amplicons by the CP-5' system and DNA fingerprinting by RAPD analysis, PCR-RFLP analysis showed an identical pattern except for a strain. RAPD patterns generated showed identical patterns within each outbreak and different patterns between outbreaks. These results indicated that the PCR methods and the molecular epidemiologic methods examined here may be available for the investigation of enterotoxigenic C.perfringens.
Bacillussp. in three samples of salty natto were studied quantitatively. and qualitatively. Three salt-resistant strains, all of B. subtilis, were selected from many strains of Bacillus sp. The growth of these strains was observed in the presence of 2.5M NaCl but not 3M NaCl. However B. subtilisATCC 12879 and B. subtilis MAFF 10-08100 (B. natto Miura strain) could not grow in the presence of 1.5M or 2M NaCl. The growth of the three salt-resistant B. subtilis sp. strains was not observed in the presence of 3.4M ethylene glycol which was equal in osmotic pressure to 2M NaCl. Thus, the stress-resistant growth was attributed to salt resistance. The growth of the three salt-resistant B. subtilis sp. strains was slower in high NaCl concentrations than in low NaCl concentrations. This suggested that adaptation to a high salty environment took time. It was of interest that salt-resistant B. subtilis sp. were the predominant strains in the microbial environment of salty natto.
In a newly-built layer processing plant in Shizuoka prefecture, a survey of bacterial contamination was conducted and the adequacy of improvements aimed at minimizing the level of contamination was assessed. The carcasses after defeathering and after chilling as well as finished chicken products showed rather heavy bacterial contamination, a mean standard plate count (SPC) of log 3.7 CFU/cm2 (3.7), 3.1 and 4.3, respectively. After improving in the defeathering machines and maintaining chlorine concentration at a level of 0.4 ppm in the chilling water, SPC on the carcasses after defeathering was adequately decreased to 3.0, but that in chiken products was inadequately decreased to 4.2. When the products were processed by workers wearing disposable rubber gloves, SPC of the chicken products decreased to 3.4. These findings suggested that the bacterial contamination of the products was due to the workers wearing cotton gloves, and also indicated that bacterial control management of the gloves worn is indispensable to the production of sanitary chicken products at this plant.