ABSTRACT
The prevalence of Escherichia coli O157:H7 on beef subprimal cuts intended for mechanical tenderization was evaluated. This evaluation was followed by the assessment of five antimicrobial interventions at minimizing the risk of transferring E. coli O157:H7 to the interior of inoculated subprimal cuts during blade tenderization (BT) or moisture enhancement (ME). Prevalence of E. coli O157:H7 on 1,014 uninoculated beef subprimals collected from six packing facilities was 0.2%. Outside round pieces inoculated with E. coli O157:H7 at 10(4) CFU/100 cm2 were treated with (i) no intervention, (ii) surface trimming, (iii) hot water (82 degrees C), (iv) warm 2.5% lactic acid (55 degrees C), (v) warm 5.0% lactic acid (55 degrees C), or (vi) 2% activated lactoferrin followed by warm 5.0% lactic acid (55 degrees C) and then submitted to BT or ME. Prevalence (n=196) of internalized (BT and ME) E. coli O157:H7 was 99%. Enumeration of E. coli 0157:H7 (n=192) revealed mean surface reductions of 0.93 to 1.10 log CFU/100 cm2 for all antimicrobial interventions. E. coli O157:H7 was detected on 3 of the 76 internal BT samples and 73 of the 76 internal ME samples. Internal ME samples with no intervention had significantly higher mean E. coli O157:H7 populations than did those internal samples treated with an intervention, but there were no significant differences in E. coli O157:H7 populations among internal BT samples. Results of this study demonstrate that the incidence of E. coli O157:H7 on the surface of beef subprimal cuts is low and that interventions applied before mechanical tenderization can effectively reduce the transfer of low concentrations of E. coli O157:H7 to the interior of beef subprimal cuts.