Influence of conventional and Kosher slaughter techniques in cattle on carcass and meat quality

The aim of this study was to evaluate and compare the influence of conventional and Kosher slaughter techniques in cattle on carcass and meat quality parameters. The conventional slaughter was done using a pneumatic captive bolt gun to stun the animals before sticking, while Kosher slaughter was done by sticking the animals and then stunning them with a 0.22 calibre cash special captive bolt gun, 20 seconds later. The animals (n=311) were randomly assigned into 4 treatment groups, namely; slaughter method (SM) (main group, sub-divided into: conventional slaughter technique (CST) and Kosher slaughter technique (KST)); electrical stimulation (ES), sub-divided into: electrically stimulated (ES) and non-stimulated (NES); gender (G), sub-divided into: male (M) and female (F); fat code (FC), sub-divided into: FC-2 and FC-3 (i.e. lean to medium fatness). The quality attributes evaluated were blood loss (BL), drip loss (DL), cooking loss (CL), presence of blood in the trachea (BLT), blood splash in the lungs (BS), shear force (SF), colour (L*, a* and b*), pH and temperature profile over 24 hours and the effect of subcutaneous fat thickness (SCF). Animals were mainly steers in the “A” age group with an average slaughter weight of about 400 kg. Different crossbreeds of Bonsmara, Brahman and Nguni cattle were used, which is typical of cattle slaughtered in South Africa. Blood loss, blood in trachea and blood splash were evaluated using 311 animals (CST, n=141; KST, n=170) but for the other parameters, smaller numbers were used because of the hectic nature of the trials. Evaluation of BL, BLT and BS were done in the abattoir and pH and temperature readings were also taken at 45 mins, 3, 6, 12 and 24 hrs post-mortem between the 10th and 11th rib on the m. longissimus dorsi which was where the carcasses were sampled for the meat quality analyses. The results of this study revealed that there was no significant difference (p> 0.05) in % blood loss between the conventional and the Kosher group but the conventionally slaughtered group had a slightly higher bleed-out. Fat code had a significant (p= 0.0475) influence on %BL, with FC-2 (2.42%) group bleeding out slightly more than FC-3 (2.24%). For % drip loss, there were no significant differences (p> 0.05) between all the treatment groups except for fat code (p= 0.0242), with FC-3 (2.95%) samples exuding more water than FC-2 (2.42%) meat samples. In terms of % cooking loss, there was a significant difference (p= 0.0004) between the slaughter methods, with meat samples from the conventional method (22.11%) exuding more water than the meat from Kosher group (18.16%). For blood in trachea, there was a highly significant difference (p 0.05) in all the treatments save for fat code, with FC-3 group (6.38) having thicker fat cover (p= 0.0004) than FC-2 (4.44) which was anticipated. In terms of colour, there was a significant difference (p< 0.0001) between slaughter methods for the L* value (lightness). Meat samples from the Kosher-killed animals (46.08) were lighter than the conventionally killed ones (35.40). Samples from the females (48.29) were also significantly lighter (p= 0.0057) than the males’ (37.79). For a* value (redness), there was a significant difference (p< 0.0001) between the slaughter methods. The conventional group meat (15.58), were redder than the Kosher meat (10.40). Gender effect was also significant (p< 0.05), with meat from the males (13.81) appearing redder than the females’ (11.25). For b* value (yellowness), significant difference (p< 0.0001) was also found between the slaughter methods. The Kosher meat samples (-6.49) appeared yellower than those from conventional slaughter (0.26). FC-3 samples (-2.36) were also significantly (p= 0.0112) yellower than the FC-2 samples (-3.05). For pH, analyses revealed a significant difference (p< 0.0380) at 45 minutes post-mortem (pm) between slaughter methods. The kosher carcasses (pH= 6.43) had a slightly higher pH compared to the conventionally slaughtered carcasses (6.33). The ES carcasses (pH=6.16) also had a significantly lower (p< 0.0001) pH compared to the NES carcasses (pH=6.89). At 3hrs pm, only electrical stimulation showed a significant influence (p< 0.0001). The ES carcasses (pH= 5.72) were lower than the NES group (pH= 6.49). At 6hrs, only electrical stimulation still showed a significant influence (p< 0.0001), with the ES carcasses (5.56) still having a faster decline compared to the NES group (pH= 6.01). At 12hrs, the ES group (pH= 5.61) still had a significantly (p= 0.0008) lower pH than the NES group (pH= 5.82). At 24hrs, only the slaughter method showed a significant influence (p= 0.0314) in carcass pH, with the Kosher carcasses (pH= 5.53) having a slightly lower pH compared to the conventionally slaughtered ones (pH= 5.56). The latter difference is probably not of any practical significance and could be ignored. Temperature at 45 minutes pm showed a significant difference (p= 0.0248) between the slaughter methods with the carcasses from Kosher slaughter (36.500C) having a slightly lower temperature compared to those slaughtered conventionally (37.220C). At 3hrs pm, the carcasses from Kosher slaughter (30.060C) had a significantly higher (p= 0.0005) temperature than the conventional group (27.050C). The female carcasses (31.260C) also had significantly higher (p< 0.05) temperature compared to the male carcasses (27.890C). The FC-2 carcasses (28.190C) also had a significantly lower temperature (p= 0.0149) compared to FC-3 (30.110C) which was anticipated due to lower temperature decline in those with lower subcutaneous fat. At 6hrs pm, the conventionally slaughtered carcasses (14.710C) still showed a significantly faster decline (p< 0.0001) compared to those slaughtered by Kosher (20.16). FC-2 carcasses also showed a significantly (p= 0.0104) lower temperature (16.680C) compared to FC-3 (18.740C). At 12 hrs pm, the conventionally slaughtered carcasses (4.720C) still had a significantly (p< 0.0001) lower temperature compared to the Kosher group (10.240C). The FC-2 group (6.690C) also had a significantly (p= 0.0011) lower temperature compared to the FC-3 group (8.890C). Finally at 24 hrs after slaughter, slaughter method still showed a highly significant influence (p< 0.0001) with the conventionally slaughtered carcasses having a much lower temperature (-0.420C) compared to the Kosher group (3.060C). The male’ carcasses (0.620C) also had significantly lower (p< 0.05), ultimate temperature compared to carcasses from the females (2.990C). There was also a significant difference (p< 0.05) between the fat codes, with the FC-2 carcasses (1.010C) showing a lower temperature, compared to the FC-3 (1.710C) carcasses. CopyrightDissertation (MSc)--University of Pretoria, 2012.Animal and Wildlife SciencesUnrestricte

Effects of timing and duration of low voltage electrical stimulation of light and heavy carcasses on meat quality of South African feedlot cattle

The study was designed to evaluate the effects of timing and duration of low voltage electrical stimulation (LVES) of light and heavy beef carcasses on meat and carcass quality of South African commercial feedlot cattle. It was inspired by the variations in meat quality that were emanating from the various electrical stimulation protocols by meat processors and the negative impact of this quality variation on the profitability of the meat industry. It was also inspired by the increasing live and carcass weight of cattle owing to better nutritional interventions and the use of feed additives and the impact on post-slaughter processing in relation to meat quality. It is believed that more meat could be produced from fewer heavier cattle compared with larger number of smaller or lighter cattle. However, the quality of meat, for example, shear force (SF), water holding capacity (WHC), drip loss (DL) and colour, from these heavier animals needs to be evaluated in order to ascertain the advantages and/or disadvantages, compared with lighter carcasses. To better understand the effects of treatments on meat quality, proteolytic enzyme activity, muscle energy metabolites and histological parameters were evaluated. Carcasses were subjected to LVES (110 V) applied early (7 min) or late (45 min) post-mortem (pm), for shorter (30 s) or longer (60 s) duration on heavy or lighter carcasses. Meat quality evaluations were done to ascertain the effects of the treatments (i.e. carcass weight, ES duration and time of ES application) and their interactions at 3 and 14 days pm (dpm). This was done to determine the values of the various quality parameters at the abattoir/butchery (3 dpm) and display period (14 dpm). Analyses revealed that early application of electrical stimulation (ES), especially on the heavier carcasses produced the highest rigor temperature (> 35 ᴼC), which produced the lowest (P < 0.05) meat SF at 3 and 14 dpm. However, early ES application was disadvantageous for meat WHC and DL, as higher (P < 0.05) DL and lower WHC were recorded, especially in the heavier carcasses. The interaction of shorter ES and heavier carcass weight favoured (P < 0.05) meat SF at 3 days pm. Longer ES did not favour WHC at 3 and 14 dpm. Heavier carcasses exhibited lower (P < 0.05) WHC and higher DL at 3 dpm, but at 14 days of ageing, there were no significant differences between the two weight categories. In terms of meat lightness (L*), early ES and longer ES produced the lightest (P < 0.05) meat at 2 and 14 dpm regardless of carcass weight. The interaction of early ES and longer ES also produced the highest (P < 0.05) L* at 2 and 14 days pm. Early ES produced the highest (P < 0.05) chroma (C*), at 2 dpm. The interaction of early ES and heavier carcasses also produced a significantly higher (P < 0.05) C* at 2 days pm. On the other hand, the interaction of late application and longer duration of ES produced higher (P < 0.05) C* at the display period (14 dpm). Regarding hue angle (H*), early ES produced higher (P < 0.05) H* at 2 dpm, but at 14 days pm, late ES produced higher (P < 0.05) H*. Heavier carcasses exhibited higher but not significant H* at 2 dpm, but at the display period, heavier carcasses exhibited lower (P < 0.05) H*. Furthermore, the interaction of early ES and longer duration of ES brought about higher (P < 0.05) H* at 2 and 14 dpm. Overall, early LVES on heavier carcasses favoured SF and C* especially at the butchery period but as the meat aged, the advantages diminished. Drip loss and WHC were also marginally disadvantaged by early ES, but these could be minimized by shorter ES. This shows that quality heavier carcasses, which favour slaughter house pricing, could be produced and processed alongside smaller carcasses with better managed LVES. The use of LVES has the potential to reduce variability in meat quality while reducing occupational risk to meat workers.Thesis (PhD)--University of Pretoria, 2018.Animal and Wildlife SciencesPhDUnrestricte

Effect of slaughter technique on bleed-out, blood in the trachea and blood splash in the lungs of cattle

The South African Animal Protection Law, which requires animals to be stunned before slaughter, allows certain exemptions to accommodate religious slaughter. The supporters of the Jewish method of slaughter (Shechita), in which animals are slaughtered without pre-stunning, claim that the bleed-out and some quality parameters are better than when the animals are stunned before slaughtering. In this study, the percentage blood loss (BL%), presence (%) of blood in the trachea (BLT%) and blood splash % in the lungs (BS%), between the Shechita (Kosher) group and the conventionally slaughtered group of cattle were compared. Results showed no significant difference between the two treatment groups in terms of blood loss, although the conventional group had a higher bleed-out. However, there were significant differences in the presence of blood in the trachea and blood splash in the lungs, with the Kosher group having the highest percentages of these quality defects. Out of 170 animals examined for Kosher, 93% had blood lining the trachea, ranging from one to over 50%. From the 141 animals examined for the conventionally-slaughtered group, 97% had no blood lining the trachea while the remaining 3% had less than 10% blood lining the trachea. Furthermore, 65% of animals slaughtered in the Kosher way had blood splash ranging from 5% to over 50%, while the conventional group had only 0.7% incidence of blood splash in the lungs. These results show that slaughtering animals without stunning do not improve bleed-out, but increase blood in the trachea and blood splash in the lungs.This work was funded by the Red Meat Research and Development of South Africa (RMRD-SA).http://www.sasas.co.za/am201

Timing and duration of low voltage electrical stimulation on selected meat quality characteristics of light and heavy cattle carcasses

CONTEXT : The present study investigated the effects of several electrical-stimulation parameters with conventional chilling of heavy- and light-grade carcasses from commercial feedlot cattle on selected meat-quality attributes. AIMS : The aim was to determine the combination of electrical-stimulation parameters that produced the most desirable results in terms of meat quality, which will serve as a guide to processors seeking to enact best processes in the meat industry. METHODS : Low-voltage electrical stimulation (110 V peak, 17 pulses/s, 5-ms pulse width) was applied either early post-mortem (PM) at 7 min or late PM at 45 min, for either 30 or 60 s on steer carcasses (n = 98) divided into two weight categories (light (≤260 kg) and heavy (≥290 kg) grades). The Longissimus lumborum muscle was evaluated for sarcomere length, myofibril fragment length (MFL), calpain-1, calpastatin, shear force and drip loss (3 and 14 days PM). KEY RESULTS : There were no significant differences in sarcomere length and no sarcomere shortening was observed. There were minor inconsistencies where early stimulation coincided with marginally longer MFL at 3 and 14 days PM, while late stimulation produced the shortest MFL at 14 days PM. Higher decline in calpain-1 concentration (mean 36.2%) was recorded in the early stimulated carcasses compared with the late stimulated carcasses (mean 29.7%) from 1 to 24 h PM, while calpastatin concentration decreased at a similar rate (mean 24%). Early stimulation resulted in lower shear force (P < 0.05) at 3 days PM, especially in the heavier carcasses, indicating that higher initial temperature did accelerate tenderisation. At 14 days PM, there were no significant differences in shear force as regards stimulation time or carcass weight. Higher drip loss was however recorded in the early stimulated carcasses. CONCLUSIONS : Early application of low-voltage electrical stimulation produced faster tenderisation early PM, due to higher rigor temperature, but, after aging for 14 days, all meat was acceptably tender with a lower variability, regardless of the stimulation time and carcass weight. Higher drip loss was associated with higher tenderness, which is normal and not a defect. IMPLICATIONS : The use of low-voltage electrical stimulation should be encouraged for its ability to reduce variability in meat quality due to carcass-weight differences, especially in the current feedlot systems.The Red Meat Research and Development Trust of South Africahttp://www.publish.csiro.au/anhj2021Animal and Wildlife Science

Electrical stimulation and carcass size : interactions between pH, temperature decline and instrumental shear force

The time of application and duration of electrical stimulation (ES) on light and heavy carcasses of Zilmax treated animals poses new challenges in the meat processing industry in South Africa. Owing to the use of Zilmax, larger carcasses are now processed at abattoirs that were built to accommodate smaller carcasses. This creates challenges in terms of optimising muscle to meat conversion using ES and the appropriate chilling regime.https://www.afma.co.za/afma-matrixhj2020Animal and Wildlife Science

Influence of electrical stimulation on carcass and meat quality of Kosher and conventionally slaughtered cattle

In a previous study regarding the effects of Kosher and conventional slaughter techniques on carcass and meat quality of cattle, it was speculated that electrical stimulation may have affected some of the meat qualities. Therefore, the objective of this study was to investigate the effects of electrical stimulation (ES) and non-electrical stimulation (NES) on key carcass and meat quality attributes of cattle slaughtered by Kosher vs. conventional slaughter methods. Carcass pH and temperature profiles over a 24 h post mortem (pm) period, meat shear force and water holding capacity were investigated in feedlot type cattle of comparable weights and breed types. Results showed that the combined effects of slaughter methods did not influence the meat quality attributes, but there were differences within the slaughter groups. The effect of ES on carcass pH lasted longer within the conventionally slaughtered group (12 h), than in the Kosher slaughter group (6 h). Muscle samples from the ES groups for both slaughter methods were more tender. Electrical stimulation also had a significant effect on the cooking loss from Kosher meat, while there was no significant difference in meat from the conventional slaughter methods. The results show that ES influences certain meat and carcass quality attributes of cattle, based on the way cattle were slaughtered.The Red Meat Research and Development of South Africa (RMRD-SA)http://www.sasas.co.za/am201

Influence of Kosher (Shechita) and conventional slaughter techniques on shear force, drip and cooking loss of beef

The objective of this study was to evaluate the effects of Kosher (Shechita) and conventional slaughter methods on shear force, drip and cooking losses of beef (m. longissimus dorsi samples) from South African feedlot cattle. Results revealed significantly lower shear force values for meat samples from cattle slaughtered by the Kosher method compared to those from cattle slaughtered by the conventional slaughter method. Cooking loss was significantly higher for meat samples from cattle slaughtered in the conventional way compared to those from cattle slaughtered by Kosher method. However, no significant difference was observed for drip loss between slaughter methods. These findings suggest that captive bolt stunning before sticking resulted in higher cooking losses and yielded less tender meat compared to the Kosher slaughter method.The Red Meat Research and Development of South Africa (RMRD-SA).http://www.sasas.co.zaam201

Nasal carriage of methicillin resistant Staphylococcus aureus among medical students of a private institution in Ilishan-Remo, Ogun State, Nigeria

Background: Nasal carriage of methicillin resistant Staphylococcus aureus (MRSA) is a major factor for its transmission especially from the health workers and medical students to their patients. There are a number of published data on the prevalence of MRSA among health workers but data on nasal colonization of medical students by MRSA are sparse in Nigeria. The objectives of this study are to determine the prevalence of nasal carriage of MRSA among medical students of the Ben Carson School of Medicine, Babcock University, Ilishan-Remo, Ogun State, Nigeria, and identify risk factors associated with this nasal carriage. Methodology: A case control study involving 100 clinical (study group) and 100 pre- clinical (control group) medical students was undertaken between March 2018 and October 2019. Structured questionnaire was administered to obtain socio-demographic information and potential risk factors. Nasal swab was collected from each student and cultured for isolation of S. aureus by standard microbiology techniques. Phenotypic MRSA was detected by the cefoxitin 30μg disk diffusion method according to the guideline of Clinical and Laboratory Standards Institute. The mecA gene was detected by conventional polymerase chain reaction (PCR) assay. Results: The prevalence of S. aureus nasal carriage among the study group was 14% (14/100) while the prevalence among the control group was 6% (6/100) (p=0.097). The prevalence of phenotypic MRSA among the study group was 4% (4/100) and 1% (1/100) among the control group (p=0.3687) while mecA gene was detected in 3 of the 4 (75%) phenotypic MRSA positive study participants and in the only (100%) phenotypic MRSA positive (1%) control group. Antibiotics usage without prescription, antibiotic treatment of common cold, and use of antibiotics in the previous one year, were significantly associated with MRSA carriage among the study group. Conclusion: Although the prevalence of nasal carriage of S. aureus and MRSA among clinical and pre-clinical medical students was not statistically significant, the risk factors identified with carriage of MRSA among the study group indicates the need for antimicrobial stewardship program to reduce carriage and transmission of MRSA by medical students. Keywords: methicillin resistant, Staphylococcus aureus, mecA gene, nasal carriage, medical student

Influence of carcass weight on meat quality of commercial feedlot steers with similar feedlot, slaughter and post-mortem management

The effects of beef carcass weight on muscle pH/temperature profile and selected meat quality attributes were evaluated. Twenty-six carcasses from light (≤ 260 kg, n = 15) and heavy (≥ 290 kg, n = 11) feedlot steers were randomly allocated and stimulated with low voltage electrical stimulation (LVES) for 30 s at 7 min post-mortem (pm). Quality evaluations were carried out on samples from the Longissimus et lumborum (LL) muscle from the left side of each carcass. Heavier carcasses showed faster pH decline and slower (P 35 °C) but there was no sign of sarcomere shortening in any carcass. Significantly lower (P 0.05) drip loss at 3 and 14 days pm as well as higher L* (meat lightness) (P < 0.05) and C* (chroma) (P < 0.05) values early (2 days) pm. However, at 14 days pm, there were no significant differences between the light and heavy carcasses in terms of L* and C*. No significant difference was observed between heavy and light carcasses in terms of H* at 2 and 14 days pm. The study showed that heavier carcasses which favor slaughter house pricing can be produced and processed alongside lighter carcasses without significant detrimental effects on meat quality by using low voltage electrical stimulation (LVES).The Red Meat Research and Development Trust of South Africa and National Research Foundation of South Africa.http://www.elsevier.com/locate/foodreshj2019Animal and Wildlife Science