Heat tolerance of Salmonella typhimurium DT104 isolates attached to muscle tissue

Eight separate experiments were performed with three isolates of Salmonella typhimurium DT104 to examine the impact that attachment to pork muscle tissue has on heat tolerance. In five experiments, attachment to muscle increased heat tolerance. For example, in one experiment the D (58 degrees C) value increased from approximately 2 min for free cells, to > 10 min for attached cells. In three other experiments, differences between free and attached cells were not so pronounced, although attached cells were still more tolerant. This suggests that muscle attachment, which may occur naturally during the preparation of comminuted meat products, could permit greater survival during subsequent cooking and thus may be a possible explanation for the involvement of cooked foods in outbreaks/cases of infection with Salm. typhimurium DT104.