At 4 C (168 h), although pathogen levels decreased slightly in the substrates, numbers of adherent cells remained constant on coupons in ground beef (2.4 to 2.5 log CFU/cm2) and increased on coupons in TSB and fat-lean tissue homogenate by 0.9 to 1.0 and 1.7 to 2.0 log CFU/cm2 , respectively, suggesting further cell attachment.