2.2. Preparation of bacterial cell and spore suspensions
Laboratory stock cultures were enriched by culturing in TSB
(10 ml) in screw-cap tubes. B. cereus and L. monocytogenes were
incubated at 30 C for 24 h, and E. coli O157:H7, S. Typhimurium,
and S. aureus were cultured at 37 C for 24 h. Cultures containing
individual strains were then mixed in a sterile plastic 50 ml