Contamination of game carcasses during harvesting and slaughter operations at a South African abattoir

[摘要] ENGLISH ABSTRACT: The consumption of game meat and its by-products is increasing locally and internationally. The increase in consumption requires research that is focused on the microbiological quality of game meat. The harvesting and slaughter process of springbok carcasses revealed the presence of bacterial contamination. Swab samples taken after skinning portrayed a presence of Escherichia coli (E. coli) and Enterobacteriaceae. Springbok carcasses swabbed after chilling indicated aerobic bacteria, Clostridium spp. and lactic acid bacteria. In contrast, swab samples taken at the evisceration's incision area tend to be lower in counts when compared to swab samples taken after skinning and after chilling. Bacterial contamination was linked to poor hygienic practices during the harvesting and slaughter process. Results showed a need for the investigation of the slaughter process. To evaluate the slaughter process's impact on the microbial quality of game carcasses, black wildebeest (Connochaetes gnou) carcasses were sampled throughout the slaughter process. Before skinning, aerobic bacteria, Enterobacteriaceae, and E. coli were enumerated from hide samples, counts ranged from 0.92 to 7.84 log cfu/g. after skinning, bacterial counts ranged from 0.93 to 6.12 log cfu/g and further decreased after chilling. Clostridium spp. counts increased after skinning, however, statistical analysis detected no significant differences between counts. Salmonella spp. was not detected. The results indicate that bacterial contamination does occur during the slaughter process. Hygienic status during the production of game meat products was also determined. Bacterial counts from raw game meat ranged from 2.37 to 5.37 log cfu/g. Counts as high as 6.16 log cfu/g were enumerated from retail products. Aerobic plate counts (APC) from ≤ 2.62 log cfu/cm2 to ≤ 6.3log cfu/cm2 were enumerated from surfaces, hands and equipment during production. Results highlighted the inefficiency of cleaning procedures and revealed that contaminated meat can allow for bacterial contamination. To determine if muscle pH influences colour stability and microbial spoilage of game meat, normal (n=6) and dark, firm and dry (DFD) (n=6) black wildebeest Longissimus thoracis et lumborum (LTL) muscles were studied. pH affected colour, as initial (day 0) L*,a*,b*,C* and Hab values from Normal pH samples were significantly higher than values reported for DFD samples. Initial APC and Enterobacteriaceae counts from samples with Normal pH were not significantly different from counts reported for DFD samples. Initial contamination was linked to the harvesting and slaughter process. Further refrigeration (5±1ºC) for 12 days in an aerobic environment and analyses of samples every third day revealed that pH did not affect lightness and brownness as L* and b* values for DFD samples did not significantly differ overtime, the same trend was seen for samples with Normal pH. Normal pH samples showed a significant increase in a* and C* values until day 12, whilst Hab values decreased until the 12th day. The same trend was seen for a* and C* values for DFD samples until the 9th day as on the 12th day values increased. Similarly, Hab values for DFD samples decreased until the 9th day, then increased on the 12th day. Using the microbial spoilage limit of 6 log cfu/g, it was seen that DFD meat reached this limit earlier than samples with Normal pH. Overall, the study provides baseline information on the microbiological quality of game meat harvested in South Africa and slaughtered at a South African abattoir.

[发布机构] Stellenbosch University