Staphylococcal food poisoning represents the most prevalent foodborne intoxication worldwide. It is caused by oral intake of enterotoxins preformed by Staphylococcus aureus in food. The relevance of newly described enterotoxins in outbreaks of staphylococcal food poisoning is controversially discussed. Although the staphylococcal enterotoxins SEG, SEI, SEM, SEN, and SEO elicit emesis in a monkey feeding assay, there has been no conclusive proof of their emetic activity in humans. In this study, we provide further evidence suggesting that one of these enterotoxins or a combination of SEG, SEI, SEM, SEN, and SEO cause staphylococcal food poisoning. We investigated two outbreaks registered with the Swiss Federal Office of Public Health, in which only Staphylococcus aureus strains harboring the egc cluster, including seg, sei, sem, sen, and seo linked to typical signs of staphylococcal food poisoning were isolated. The outbreaks were caused by consumption of raw goat cheese and semi-hard goat cheese, and were linked to strains assigned to CC45 (agr type I) and CC9 (agr type II), respectively. These outbreaks provide further evidence that newly-described staphylococcal enterotoxins are likely to cause staphylococcal food poisoning in humans.

was used to analyze food for the presence of Listeria monocytogenes. Food samples were artificially contaminated to develop two procedures to detect the organism following enrichment steps. Procedure A was based on dilution of the enrichment broth followed by lysis of the bacteria and direct analysis of the lysate with PCR. With procedure A and artificially contaminated food samples, it was possible to detect fewer than 10 bacteria per 10 g of food. In procedure B, centrifugation was used to concentrate bacteria before lysis and PCR. With procedure A, 330 naturally contaminated food samples of several types were analyzed. Twenty samples were found to be positive for L. monocytogenes, which was in agreement with the classical culture technique. By using procedure B on a subset of 100 food samples, 14 were found to be positive by PCR whereas the classical culture method detected only 13. Analysis times, including enrichment steps, were 56 and 32 h with procedures A and B, respectively.

Hazard analyses were done at 11 cooked-food-vending sites and related food-vending operations in a small-town market along a highway in Zambia. The analyses consisted of observations and time-temperature measurements at the vending sites and interpretations of results of laboratory tests of samples of foods (including leftovers) collected after holding and reheating. Salmonellae were isolated from dried ants, a cooked meatball on display, and pumped river water used by the vendors. Ants for sale at the market contained 107 Bacillus cereus cells per g. Nshima (boiled maize meal) was held at high temperatures in pans over glowing charcoal in which steam was generated throughout the entire holding period during the day, preventing bacterial growth. Large populations of B. cereus, however, were isolated from a sample left overnight at ambient room temperature. Cooked foods other than nshima were held at room or outdoor ambient temperatures throughout the day and overnight. High aerobic mesophilic colony, thermotolerant coliform and, in a few foods, Escherichia coli counts were found in foods after several hours of holding during the day of preparation and of foods held overnight. Temperatures attained during reheating were variable and sometimes would have resulted in survival of foodborne pathogens that multiplied during holding.

We present here the full-length genome sequences of two hepatitis E virus genotype 3 (HEV-3) isolates from a human stool sample from a patient with acute hepatitis and a raw sausage containing pig liver. Sequence analysis implies that Swiss HEV isolates may form a novel subgroup of HEV-3 viruses.

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