Three transfers needed to
achieve activation of strains. Cocktail of this strains were
arranged by placing 0.25 mL from each strain in one tube
to get 9 log cfu/mL. Then serial dilution was prepared in
(0.1% w/v) peptone water (Becton Dickinson, Sparks, MD)
to decrease the initial level of E. coli to 6 log cfu/mL.