Browsing by Author "Shange, Nompumelelo"

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    Contamination of game carcasses during harvesting and slaughter operations at a South African abattoir
    (Stellenbosch : Stellenbosch University, 2015-12) Shange, Nompumelelo; Hoffman, Louwrens C.; Gouws, Pieter Andries; Stellenbosch University. Faculty of Agrisciences. Dept. of Food Science.
    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.
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    The prevalence of Campylobacter and Arcobacter species in ostriches from South Africa
    (Stellenbosch : Stellenbosch University, 2020-04) Shange, Nompumelelo; Gouws, Pieter Andries; Hoffman, Louwrens C.; Stellenbosch University. Faculty of AgriSciences. Dept. of Food Science.
    ENGLISH ABSTRACT: The overall aim of this thesis was to determine the prevalence of Campylobacter and Arcobacter species in ostriches from South Africa. In humans Campylobacter and Arcobacter species can cause of gastroenteritis, Guillian Barré syndrome, septicaemia and bacteraemia. Previous research has indicated that the consumption of contaminated poultry meat is the main route of infection for humans and by extension poultry species are deemed primary reservoirs of Campylobacter and Arcobacter species. Currently, there is a lack of information regarding Campylobacter and Arcobacter species in relation to ostriches from South Africa. Artificially and naturally reared ostrich chicks at the age of 2, 4, 6 and 12 weeks were sacrificed, and caeca samples were excised. Campylobacter spp. (C. jejuni) was detected in artificially reared chicks, on the 12th week. A persistent presence of Arcobacter (A. skirrowii) was detected from the 2nd until 12th week of life for both artificially and naturally reared ostrich chicks. Additionally, cohorts that belonged to the same batch as the sacrificed ostrich chicks, regardless of the rearing process were sampled at the slaughter age of 10 and 12 months. Arcobacter spp. (A. skirrowii) and Campylobacter spp. (C. jejuni) were isolated from 56-70% of slaughter age birds. Cloacal swabs were also obtained from live ostriches reared on 30 different farms situated in South Africa (Oudtshoorn). Cloacal swabs were processed with family specific PCR (n = 168 pooled cloacal swabs), the Cape Town protocol (n = 836 cloacal swabs), ISO 10272-1:2006 (n = 836 cloacal swabs) and a selective Arcobacter spp. method (n = 415 cloacal swabs). Family specific PCR determined an average prevalence of 24.63%. The ISO 10272-1:2006 method and Cape Town Protocol determined a prevalence of 16.83% and 0% for Campylobacterspp., respectively. For Arcobacter spp. a prevalence of 18.80% and 39.14% was determined with the Cape Town protocol and selective Arcobacter spp. method, respectively. Higher prevalence levels were determined when ostriches were sampled during spring and autumn, respectively. Higher prevalence levels were also detected in ostriches reared on farms that made use of borehole water. Higher prevalence levels were seen for ostriches reared on farms with wild water birds. During slaughter, Arcobacter spp. were detected at a prevalence level of 73% at post-skinning. At post-evisceration, 73% and 83% of samples were contaminated with Campylobacter spp. and Arcobacter spp., respectively. At post-chilling, 66% and 67% were contaminated with Campylobacter spp. and Arcobacter spp., respectively. Additionally, a second study to evaluate the occurrence of Campylobacter spp. and Arcobacter spp. was conducted to see whether routine testing was required for abattoirs. E. coli and coliforms were also enumerated to determine the occurrence of faecal contamination during slaughter. Overall, a low occurrence of Campylobacter spp. (0.98% and 0%), Arcobacter spp. (1.31% and 1.64%), E. coli (0.13 log cfu/g) and coliforms (0.53 log cfu/g) was determined for all three abattoirs. Antibiotic resistance in Campylobacter spp. and Arcobacter spp. isolated from ostriches and ostrich meat was determined. Campylobacter spp. and Arcobacter spp. isolates were generally resistant to antibiotics in the following order cephalothin, vancomycin and erythromycin and tetracycline. The majority of Campylobacter spp. (92.86%) and Arcobacter spp. (80.95%) isolates exhibited multi-drug resistance. Overall, this research shows that ostriches from South Africa can be considered as potential carriers of species belonging to the Campylobacteraceae family and infection can occur at young age. Carcasses can be contaminated during slaughter and species carried by ostriches can be resistant to essential antibiotics; ultimately highlighting the need for routine testing of Campylobacter and Arcobacter species.