| Efforts to reduce the incidence of pathogenic bacterial contamination associated with meat and poultry products have led to many developments in decontamination strategies for meat animal carcasses. This work details the validation and verification of one strategy, commercially termed "steam pasteurization", for reducing total microbial loads, as well as the incidence of pathogens, on beef carcasses. Utilizing laboratory-scale equipment, the effectiveness of the process for reducing high levels (ca. 5 log CFU/cm 2) of Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes on freshly slaughtered beef tissue was determined. Steam applied under slight pressure in an enclosed chamber with an exposure time of 15 seconds raised meat surface temperatures to approximately 93°C (200°F). Steam treatment reduced pathogen populations by 3.4 to 3.7 log CFU/cm2, and was most effective when combined with physical decontamination methods, such as knife trimming or hot-water/steam vacuuming.; The effectiveness of the process was verified in two commercial beef slaughter facilities. In the first study, samples were excised from the brisket/plate region of 140 carcasses immediately before, immediately after, and 24 h after steam treatment. The process significantly ( P≤0.01 ) reduced mean aerobic plate counts (APCs) from 2.19 log CFU/cm 2 before treatment to 0.84 log CFU/cm2 immediately after and 0.94 log CFU/cm2 24 h after treatment. E. coli (generic) was detected on 16.4% and 0% of carcasses before and after treatment, respectively. In the second study, sponge samples were collected from the inside round, loin, midline, brisket, and neck regions of 100 carcasses before and after treatment to evaluate uniformity of steam effects across carcass regions. Before treatment, mean APCs ranged from 3.4 to 4.5 log CFU/cm 2; these populations were significantly ( P≤0.01 ) reduced after treatment to 2.6 to 3.3 log CFU/cm2. E. coli (generic) was detected on 68 and 15% of carcasses before and after treatment, respectively.; Incorporation of the steam pasteurization process, namely as a critical control point in HACCP systems, significantly reduces the likelihood of enteric bacterial pathogens being carried further into carcass conversion processes. Therefore, the system can serve as an important step in improving the safety and reducing microbiological risks associated with beef products. |
