Staphylococcus aureus ATCC 6538, L. monocytogenes ATCC 19115,
Bacillus cereus C113, Salmonella enteritidis DMST 1706 and E. coli
O157:H7 DMST 12743 were used as the test organisms. The organisms
were grown in tryptic soy broth (TSB, Merck, Germany) at
37 C for 24 h with shaking (200 rpm). Each culture was harvested
by centrifugation (7500g for 10 min at 4 C) and the resulting
pellets were washed twice and resuspended in sterile 0.1% (w/v)
peptone solution. Before testing, the concentration of each bacterium
was adjusted to 107 CFU/ml with sterile peptone solution.