Reduction of Escherichia coli O157:H7 viability on hard surfaces by treatment with a bacteriophage mixture

摘要

This study determined the effect of a previously characterized phage mixture, referred as BEC8 on enterohemorrhagic Escherichia coli (EHEC) O157:H7 strains applied on materials typically used in food processing surfaces. Sterile stainless steel chips (SSC), ceramic tile chips (CTC), and high density polyethylene chips (HDPEC) were used. Cultures of EHEC O157:H7 strains EK27, ATCC 43895, and 472 were combined, spot inoculated on surfaces, and dried. Chips were inoculated with 10[super]6, 10[super]5, and 10[super]4CFU/chip, to obtain 1, 10 and 100 multiplicity of infection (MOI) values, respectively. Controls and BEC8 (approx. 10[super]6 PFU/chip) were applied on inoculated surfaces and incubated at 4, 12, 23, and 37 掳C. EHEC survival was determined using standard plate count on tryptic soy agar. At 37 掳C and 12 掳C on SSC, no survivors were detected (detection limit 10 CFU/chip) after BEC8 treatment at MOI of 100 after 10 min and at 23 掳C after 1 h on SSC. A similar result was obtained on CTC at 37 掳C after 10 min, and after 1 h at 23 掳C. These results indicated that the phage cocktail was effective within an hour against low levels of the EHEC mixture at above room temperature on all 3 hard surfaces.