Category Archives: water microbiology

Journal of Food Protection

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.