The aim of this study was to analyse the influence of the contamination level of fresh meat on the bacterial population in raw material before cooking and on the microbiota of cooked hams following heat treatment. The effect of incubation temperatures of 6.5 and 15 °C on the results obtained was also evaluated during the bacteriological investigation. The total viable count (TVC), the number of Enterobacteriaceae and lactic acid bacteria (LAB) were determined in the samples. LAB were isolated from 13 samples out of the 50 fresh meat samples. The species most frequently detected included Latilactobacillus sakei, Leuconostoc carnosum, Enterococcus gilvus, Latilactobacillus curvatus, and Leuconostoc gelidum. The meat sampled after the brine injection and tumbler massaging showed higher bacterial counts compared to fresh meat samples (p < 0.001). The heat treatment destroyed the majority of the bacteria, as the bacterial counts were beneath the limit of detection with a few exceptions. Although the primary cultivation of samples of cooked hams did not reveal the presence of LAB, their presence was confirmed in 11 out of 12 samples by a stability test. Bacteria of the genus Leuconostoc were the most numerous.

The aim of this study was to investigate the occurrence of foodborne agents at food service facilities in the Czech Republic. The sampling, performed from April 2016 to November 2017, focused on the microbiological monitoring of the environment at the establishment (EFS; n = 298) and the hands of staff (HFS; n = 159). The analysis targeted the presence of the following bacteria: Escherichia coli (focusing on the presence of Shiga toxigenic E. coli), Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Salmonella spp., and Campylobacter spp. A swab method using sterile abrasive sponges was used to detect bacteria in EFS; a glove-juice method was used to monitor microbial contamination on HFS. The presence of E. coli was confirmed in 11.8% of samples (12.4%, EFS; 10.7%, HFS; P = 0.650). The presence of Shiga toxigenic E. coli was not confirmed in the samples. B. cereus was detected most frequently, in 39.6% of all samples taken (44.6%, EFS; 30.2%, HFS; P = 0.003). S. aureus was detected in 17.9% of samples (17.4%, EFS; 18.9%, HFS; P = 0.703). Of S. aureus isolates, 58.5% were found to be positive for the presence of genes producing staphylococcal enterotoxins (70%, HFS; 52.0%, EFS). L. monocytogenes was detected in only one sample (0.2%; EFS). The presence of Salmonella spp. and Campylobacter spp. was not confirmed. The occurrence of B. cereus, S. aureus, and E. coli was dependent on the season of the year. B. cereus and S. aureus occurred less frequently in the summer months, although E. coli was recorded more frequently. B. cereus, S. aureus, and E. coli were detected in almost half of the tested samples. The relatively high percentage of B. cereus and S. aureus isolates from EFS corresponded with the model in the final European Food Safety Authority reports on the occurrence of foodborne disease outbreaks in the European Union. Managers of food service facilities should focus on reducing the occurrence of B. cereus and S. aureus. HIGHLIGHTS

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The aim of this study was to evaluate the toxigenic potential of Bacillus cereus strains isolated from frozen goat colostrum. Of the 50 phenotypically suspected B. cereus isolates, 39 (78.0 %) were confirmed as B. cereus by the polymerase chain reaction (PCR) method based on the gyrB gene detection. In these isolates, genes encoding the production of haemolysin BL (Hbl), a complex of non-haemolytic enterotoxins (Nhe) and emetic toxin were detected by the PCR method. In 36 (92.3 %) confirmed B. cereus isolates, genes encoding at least one type of toxins of interest were detected. In all toxigenic isolates, we found the presence of genes for Nhe production, and in 16 (41.0 %) of the isolates, genes encoding both Nhe and haemolysin BL were shown. Eight (20.5 %) of the emetic strains of B. cereus were identified. The emetic toxin production gene was always detected simultaneously with genes encoding non-haemolytic enterotoxin production. The ability to produce BL haemolysin and non-haemolytic enterotoxins were confirmed by the immunochromatographic method. In summary, goat colostrum can be a significant source of toxigenic strains of B. cereus.

Samples of steak tartare were artificially contaminated with a cocktail of Shiga toxin-producing Escherichia coli (STEC) O91, O146, O153, and O156 to the level of 3 log and 6 log CFU/g. Immediately after vacuum packing, high-pressure processing (HPP) was performed at 400 or 600 MPa/5 min. Some of the samples not treated with HPP were cooked under conditions of 55 °C for 1, 3, or 6 h. HPP of 400 MPa/5 min resulted in a 1–2 log reduction in the STEC count. In contrast, HPP of 600 MPa/5 min led to the elimination of STEC even when inoculated to 6 log CFU/g. Nevertheless, sub-lethally damaged cells were resuscitated after enrichment, and STEC was observed in all samples regardless of the pressure used. STEC was not detected in the samples cooked in a 55 °C water bath for 6 h, even after enrichment. Unfortunately, the temperature of 55 °C negatively affected the texture of the steak tartare. Further experiments are necessary to find an optimal treatment for steak tartare to assure its food safety while preserving the character and quality of this attractive product.