When stainless steel, glass, plastic, and wooden coupons containing
attached E. coli O157:H7 were immersed in M9 medium and incubated
at 22 °C, the number of E. coli O157:H7 on those coupons increased
significantly (P ≤ 0.05) to 8.6, 7.9, 8.6, and 9.5 log CFU/coupon, respectively,
within 2 days and remained constant for an additional 3 days.