Food Protection Trends - July 2009 - 433

TABLE 2. Mean aerobic plate count (APC) and E. coli on sheep carcasses at Plants A–F E. coli Plant A B C D E F a n 44 30 30 37 81 58 Mean log APC/cm2 (SD) 2.9 (0.5) 3.4 (0.9) 3.2 (0.3) 1.5 (1.0) 1.9 (0.8) 3.1 (0.5) Prevalence (%) 79.5 93.3 96.7 37.9 13.6 89.6 Concentrationa 1.54 1.47 1.70 0.14 0.88 1.45 Mean log count/cm2 of positive samples (B, C and F) had none of these features and two of them (Plants B and F) used a rotary fleece puller, resulting in higher total scores. Plant A, at which line speed was managed and two operators were used at some stations, had a score intermediate between the other two groups. All six plants were sampled in the third national baseline study (16) and summary statistics of indicator organisms (APC and E. coli) isolated from their carcasses are presented in Table 2. In general, the ranking of the microbiological results of the carcass followed the ranking of the scores calculated using the software tool. Plants D and E had considerably (1–2 log) lower TVCs, E. coli prevalence and concentrations than did Plants B, C and F, with Plant A occupying an intermediate position between the two groups. DISCUSSION The Australian sheep industry is spread over a large latitudinal range with intense seasonal changes involving rainfall and temperature effects on incoming livestock. In some cases, livestock are transported over vast distances to the abattoir. Taken together, these factors account for a wide range of contamination on incoming livestock. The tool attempts to capture this variability in a Problem Score, which is establishment specific. The ability of each plant to cope with its unique incoming problem is then assessed by the Process Score for the plant. The tool removes the “one size fits all” approach to assessing slaughter and dressing, allowing each plant to be assessed on its ability to control carcass contamination through its management and operational procedures. It is emphasized that the score should be used as an indication only, not as a definitive assessment of the process. All plants already conform to the requirements of their Controlling Authorities, and no attempt should be made to “grade” plants. Ideally, the tool will be used for process improvement because it gives the Quality Assurance (QA) Manager a check list that can be used to assess potential modifications to pre-slaughter and slaughter processes. For example, a management decision such as that taken by Plant E to accept only livestock that have been crutched and have short fleeces (< 5 cm) will have clear implications on the degree of difficulty in keeping fecal contamination from meat surfaces. Once on the slaughter and dressing floor, there are a large number of operational variables that can influence carcass contamination. In addition, line speed, and the ability to modify it by adjusting it and/or using additional operators at specific work stations, is an important influence on contamination (both visual and microbiological) of bodies. The tool, while not a definitive guide, brings together various pieces of knowledge in a single place to assist QA and production staff to interrogate “whatif ” scenarios that can assist in process improvement. The tool is available from the corresponding author. ACKNOWLEDGMENTS We would like to thank the QA managers from various Australian sheep abattoirs who road tested the tool and provided valuable feedback on its usability. Jo Slade is also thanked for her help in the preparation of this manuscript, and two anonymous reviewers are thanked for the helpful comments and suggestions. REFERENCES 1. Anonymous. 1980. Proceedings of the Strathleven Centenary Symposium on Refrigeration. CSIRO Food Res. Q. 40. 2. Bacon, R. T. 2005. Physical decontamination strategies for meat, p. 318–349. In J.N. Sofos (ed.), Improving the safety of fresh meat. Woodhead Publishing Ltd. Cambridge, England. 3. Bell, R. G., and S. C. Hathaway. 1996. The hygienic efficiency of conventional and inverted lamb dressing systems. J. Appl. Bacteriol. 81:225–234. 4. Bensink, J. C. 1972. The microbiological effect of papering the hind legs of sheep carcases during dressing. CSIRO Meat Research Report 1/72. 5. Biss, M. E., and S. C. Hathaway. 1995. Microbiological and visible contamination of lamb carcasses according to preslaughter presentation status: Implications for HACCP. J. Food Prot. 58:776–783. 6. Dykes, G. 2007.The effect of different water temperatures on knife decontamination. MLA Project A.MFS.0115. JULY 2009 | FOOD PROTECTION TRENDS 433

Food Protection Trends - July 2009

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