Biofilms have a significant impact on food safety in the food industry. Many foodborne outbreaks have been associated with pathogenic strains that can form a biofilm. The present study aimed to examine the ability to form biofilms by pathogenic strains collected from retail food samples under the Official Control and Monitoring Program in Poland. Biofilm formation was assessed by the qualitative detection of EPS production on Congo Red Agar, tube method, crystal violet biofilm assay, and MTT assay. A total of 40 isolates from food samples (10 strains for each of the species Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Bacillus cereus ) were examined. . . The study classifies strains as adherent strain, slightly adherent, nonadherent (A, SA and N); as weak, moderate, and strong biofilm formation (WBF, MBF and SBF); and weak, moderate, and high metabolic activity (WMA, MMA and HMA). Incubation conditions and time influenced the biofilm levels formed. Moreover, growth medium had a significant impact on biofilm formation. Results showed that 22.5% strains demonstrated A type in LBB and 77.5% SA type in LBB in the test tube while the stronger adhesion was obtained in BHI with 2% sucrose. Among the isolates incubated in the BHI medium with 2% sucrose, A type was observed in 60% of isolates (60%).. CV assay result show that the after 24 h incubation in LBB, SBP was 7,5% while after 48 h – 37.5% tested strains. For BHI medium supplemented with 2% sucrose after 24 h incubation strains 42.5% was classified as SBP and 37.6% after 48h.MTT assay result indicate that 15% strains incubate in LBB (24h) was HMA, and after 48h incubation time HMA show 25%. For BHI medium supplemented with 2% sucrose after 24 h or 48 h incubation strains 70% and 85 % was classified as HMA.

Bacillus cereus sensu lato can contaminate food and cause food poisoning by producing toxins such as cereulide, toxin BL, and cytotoxin K. In this study, we retrospectively analyzed B. cereus sensu lato from retail food products and food poisoning cases using PCR methods to determine their virulence profiles. A new toxin profile, encoding all four toxins (hbl, nhe, cytK, ces), was found in 0.4% of isolates. The toxin profiles, classified into A-J, revealed that 91.8% harbored nhe genes, while hbl, cytK, and ces were detected in 43.8%, 46.9%, and 4.2% of isolates, respectively. Whole-genome sequencing (WGS) identified four distinct species within the B. cereus group, with 21 isolates closely related to B. cereus sensu stricte, 25 to B. mosaicus, 2 to B. toyonensis, and 1 to B. mycoides. Three novel sequence types (STs 3297, 3298, 3299) were discovered. Antibiotic resistance genes were common, with 100% of isolates carrying beta-lactam resistance genes. Fosfomycin (80%), vancomycin (8%), streptothricin (6%), tetracycline (4%), and macrolide resistance (2%) genes were also detected. These results highlight the genetic diversity and antibiotic resistance potential of B. cereus sensu lato strains in Polish food products.

Traditional and regional foods have been increasing in popularity among consumers in Poland for many years. The observed trend of searching for natural and authentic taste encourages many producers to craft products from raw milk, including Koryciński cheeses. The aim of this study was to assess the microbiological hazards resulting from the presence of pathogenic bacteria in Koryciński cheeses available in retail trade. The tests were carried out using accredited methods, including the detection of the presence of Salmonella spp., the enumeration of Listeria monocytogenes, the enumeration of coagulase-positive staphylococci, and the detection of staphylococcal enterotoxins in food when the number of coagulase-positive staphylococci in the sample exceeded the limit of 10⁵ cfu/g. The research material consisted of 45 Koryciński cheeses. The tests conducted revealed that Salmonella spp. was not detected in any of the examined cheeses. However, coagulase-positive staphylococci were present in 68.9% of the samples. In as many as 15 tested cheeses, the level of S. aureus contamination was above 10⁵ cfu/g; therefore, these samples were tested for the presence of staphylococcal enterotoxins. The presence of staphylococcal enterotoxins was found in one Koryciński cheese. In four cheeses, the number of L. monocytogenes exceeded the level of 10² cfu/g, the limit specified in Regulation 2073/2005 on microbiological criteria for foodstuffs. The obtained research results confirm the validity of monitoring the microbiological quality of Koryciński cheeses and the need to increase awareness of ensuring proper hygienic conditions of production, including the increased risk associated with unpasteurized milk products.

Introduction and objective: Bacillus cereus is a foodborne pathogen causing two main types of gastrointestinal diseases: emetic and diarrheal. The aim of this study was to investigate the prevalence of the Bacillus cereus group in ready-to-eat (RTE) food products available in retail in...

Bacillus cereus is a foodborne pathogen causing food safety issues due to the formation of difficult to eliminate spores and biofilms. The objective of this study was to investigate the occurrence of B. cereus (conducted as part of monitoring in 2017-2018) and the presence of a toxin gene in...