A xerophilic fungal strain S-1430 isolated from a spoiled mini-doughnut (aw 0 .81) was identified as Trichosporonoides nigrescens morphologically and physiologically .This isolate grew well on MY50G agar (aw 0.89) at 25°C, and grew in YES and YEG broth containing5% (w/v) ethanol, butnot 6% (w/v). This was the first isolation of this fungus from processed foods on the market .
A survey was conducted to estimate the prevalence of Salmonella and antibodies for Salmonella Enteritidis (SE) in eggs retailed in Hokkaido. For this survey, 22, 120 eggs were purchased from farms and supermarkets from January 1998 to March 1999, in Sapporo. The eggs were produced by 31 farms across all of Hokkaido breeding a total of 4.22 million laying hens, accounting 66% of 6.37 million laying hens in Hokkaido. No Salmonella was detected from any eggs tested, but 26 eggs from 13 samples were positive for egg yolk SE-antibody. One farm where one SE antibody positive egg was detected was surveyed environmentally for the prevalence of Salmonella, and Salmonellas were isolated from windowless hen houses. The bacteria were different from flock to flock. On another farm, two samples consisting of 30 eggs each yielded eight SE antibody positive eggs. Thirty spent hens obtained from this farm were tested for Salmonella isolation and SE antibody detection. Twelve of thirty hens (40%) were positive for Salmonella but neither SE nor SE antibodies were found. These results indicate that the prevalence rate of Salmonella in retailed eggs in Hokkaido is lower than the model estimates described by Ebel & Schlosser [Int. J. Food Microbiol., 61, 51-62 (2000)], but SE-antibody detection rates for these eggs were considered to be on the same level with the model. SE-antibody positive eggs were detected among the eggs produced by the farm highly contaminated with SE or Salmonella. Thus, the monitoring the egg yolk SE-antibody of retailed eggs is useful for determinig the Salmonella contamination rate of each farm, which is valuable information for controlling Salmonella food poisoning by eggs and egg products.
We investigated the distribution of Vero toxin-producing Escherichia coli (VTEC) and the incidence of pathogenesis-related factors in swine feces. The rectal content was collected from 100 macroscopically healthy pigs brought to a slaughterhouse between November 26 and December 24 in 1999. The samples were cultured in TSB medium. The Vero toxin (VT) gene was investigated by PCR, and VTEC was isolated from the VT gene-positive samples. Other pathogenesis-related factors were also investigated in the isolated VTEC. Of 100 swine fecal samples examined, 64 samples were judged positive for VT gene by PCR screening, and 27 VTEC isolates were obtained from 25 animals. On examination after the animals were slaughtered, hemorrhagic colitis was observed in two of 25 VTEC-positive animals, but no animal showed typical features of swine edema disease. The remaining pigs showed non-diarrheal symptoms or were asymptomatic. The ratio of animals showing these pathological features was not different from that in the VTnegative pigs. VT2vp1 was the most frequent VT type, detected in 22 (81%) of 27 isolates. VT1 was the second frequent type, detected in 4 (15%). Approximately 70% of the VT2vp1-producing strains produced STIa, which is associated with diarrhea in humans. A strain carrying the eaeA gene was also isolated. It should not be neglected as a public health problem.
Between August and September 1999, five outbreaks of food poisoning caused by SalmonellaEnteritidis were reported in the west of Shimane prefecture. Epidemiological studies made it clear that three outbreaks of food poisoning were caused by eggs in poultry farm A. S. Enteritidis was detected in egg shells, liquid egg and hens' feces in the poultry farm . The results of biochemical characteristics, drug sensitivities, phage typing and gene analysis by pulsed-field gel electrophoresis of the isolates from patients, eggs in farm A, and chicken feces showed the same pattern of S. Enteritidis. Therefore, we suspected at least three outbreaks of S. Enteritidis food poisonings were associated with eggs in the poultry farm.