scholarly journals Techniques to reduce the temperature of beef muscle early in the post mortem period – a review

2014 ◽  
Vol 54 (4) ◽  
pp. 482 ◽  
Author(s):  
Robin H. Jacob ◽  
David L. Hopkins

A review of the literature was conducted on the effects of high temperature and low pH (HTLP) on meat quality, with a focus on interventions that increase the rate of cooling post slaughter. HTLP can potentially change meat tenderness, water-holding capacity and colour due primarily to protein denaturation during the first 5 h post mortem. Deep muscles in large carcasses are susceptible to HTLP when cooled conventionally. Ante mortem and post mortem solutions that increase the rate of carcass cooling are discussed. Ante mortem solutions include access to feed and water, showering with water and provision of shade. Post mortem solutions included vascular flushing, hot fat trimming, opening seams, hot boning, spray chilling, blast chilling, immersion cooling, and very fast chilling. Accelerating rigor with electrical stimulation before HTLP remains controversial. Combinations of different techniques, that suit the specific requirements of a particular processing plant, is the likely best solution to HTLP, but further development of commercial solutions is suggested.

2014 ◽  
Vol 54 (4) ◽  
pp. 444 ◽  
Author(s):  
R. H. Jacob ◽  
V. S. M. Surridge ◽  
D. T. Beatty ◽  
G. E. Gardner ◽  
R. D. Warner

The core body temperature and post slaughter loin temperatures of steers fed on grass pasture was compared with those of steers fed a grain-based feedlot diet. The feeding treatments were grass for 300 days (Grass), grass for 150 days then feedlot for 150 days (Short Feedlot) and feedlot for 300 days (Long Feedlot). Temperature telemeters were inserted under the peritoneum of the steers and temperature measured at intervals of 1 h for the 300 days, and then at intervals of 1 min for the 48-h period before slaughter. The pH and temperature decline post mortem was also measured. The carcasses of the feedlot steers were heavier and fatter than those from the Grass-fed steers. The core body temperature of the steers from the feedlot treatments was 0.3–0.4°C higher than for the Grass treatment at the time of slaughter. The loin temperature was higher in the feedlot treatments than the Grass treatment at all times measured post mortem as was the temperature at pH 6. Feedlotting can increase the likelihood of ‘high rigor temperature’ conditions of high temperature and low pH occurring in beef carcasses, due to an increase in core body temperature before slaughter, a decrease in the rate of cooling and an increase in the rate of pH decline post mortem. These effects are possibly due to a combination of a direct effect of feed type on body temperature as well as indirect effects on bodyweight and condition score.


1996 ◽  
Vol 5 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Petri A. Papinaho ◽  
Daniel L. Fletcher

Experiments were conducted to determine the relationships between deboning time and broiler breast meat quality, as determined by objective meat tenderness, pH, color and cooking loss. All birds were processed in a European commercial processing plant using a high current, constant voltage stunning system and air chilling. According to a modified Mitscherlich response equation, pH values reached their ultimate value by 5.77 h post-mortem, with an asymptotic 95 % confidence interval of 5.72 h-5.81 h post-mortem. The shear force data, which were analyzed using a logistic model, suggested that broiler breast fillets should be aged intact on the carcass for 10.58 h, 5.94 h or 2.28 h to guarantee that over 95 % of the fillets reach Allo-Kramer shear forces of 8.0, 9.0 or 11.0 kg/g, respectively. Since acceptable meat tenderness values vary with country, geographical area, or consumer groups, acceptable ranges should be determined according to potential market demands. No relationships between deboning time and fresh meat color or cooking loss was found.


2013 ◽  
Vol 93 (3) ◽  
pp. 321-328 ◽  
Author(s):  
Jia-Chun Tian ◽  
Ling Han ◽  
Qun-Li Yu ◽  
Xi-Xiong Shi ◽  
Wen-Ting Wang

Tian, J.-C., Han, L., Yu, Q.-L., Shi, X.-X. and Wang, W.-T. 2013. Changes in tenderness and cathepsins activity during post mortem ageing of yak meat. Can. J. Anim. Sci. 93: 321–328. Very little research has been conducted on yak meat tenderization. In this study we investigated the changes in physical characteristics (e.g., pH, water-holding capacity, texture profile analysis, shear force) and cathepsins L, B and H activities in the tenderization process. These traits were quantified in longissimus dorsi muscle from 10 yaks during 192 h post mortem. Samples were aged at 4°C for 0, 12, 24, 36, 48, 72, 120, 168 and 192 h. pH decreased (P<0.05) from 6.84 to 5.54 in the first 72 h and did not change significantly during the next 120 h. Water-holding capacity showed an overall decreasing trend (P<0.05). Shear force decreased? (P<0.05) and myofibrillar fragmentation index increased? (P<0.05), and it was concluded that ageing can improve yak meat tenderness. Our results on texture profile analysis showed a decrease in hardness (P<0.05), springiness (P<0.05) and chewiness (P<0.05), reflected in a progressive softening during ageing (P<0.05). Cathepsins L, B and H activity showed an increased trend (P<0.05). In conclusion, our results show potential roles for cathepsins L, B and H in the tenderization process. This study provides further insights into the tenderization process of yak meat, which may ultimately be used for the advantageous manipulation of the process.


2014 ◽  
Vol 54 (4) ◽  
pp. 494 ◽  
Author(s):  
R. D. Warner ◽  
M. Kerr ◽  
Y. H. B. Kim ◽  
G. Geesink

High pre-rigor muscle temperature has negative consequences on quality and has been predominantly studied in the excised longissimus muscle of beef and lamb carcasses. There is little data on other muscles, the application in whole carcasses or potential amelioration techniques such as stretching. This study evaluated the effects of electrical stimulation, high pre-rigor temperature and stretching of lamb sides on quality traits and protein denaturation in four leg muscles [gluteus medius (GM), rectus femoris (RF), semimembranosus (SM) and semitendinosus (ST)]. Twenty lamb carcasses were used with two electrical stimulation treatments (stimulated or non-stimulated, +/−) and two pre-rigor temperature treatments (chilled at 2°C directly after slaughter, or held in 37°C water for 4.5 h before transfer to a 2°C chiller) applied. One side of each carcass was suspended from the Achilles tendon, whereas the other side was stretched by allowing the leg to drop and tying it to the ribs. Electrical stimulation did not influence the different traits except for pH fall post slaughter and myosin denaturation. Stretching resulted in greater muscle and sarcomere lengths for the GM, SM and ST, but a decrease in sarcomere length for the RF. For the non-stretched GM and SM, the 37°C treatment resulted in tougher meat at 1 and 8 days post mortem compared with the 2°C treatment. In contrast, the stretched 37°C treatment resulted in more tender meat for the GM, SM and ST at 1 day post mortem compared with the 2°C treatment. For all muscles, the 37°C treatment resulted in a decrease in the water-holding capacity (increased purge, surface exudate and cooking losses). The magnitude of this effect was generally diminished by stretching for the GM, SM and ST, but for the RF, (which was not stretched by the treatment) this effect was reversed. The 37°C treatment resulted in paler meat (increased L*-values) for the GM, SM and ST relative to the 2°C treatment. The observed effects of the 37°C treatment on water-holding capacity and colour could be explained by the effects of this treatment on indicators of protein denaturation (sarcoplasmic protein solubility and myofibrillar ATPase activity), which were decreased for the GM, SM and ST. The response to both temperature and stretching varied between the muscles, due to different anatomical location and also due to postulated differences in the fibre types. In conclusion, pre-rigor stretching of lamb sides can counteract the negative effects of high early post-mortem temperature on tenderness and water-holding capacity for those muscles that are stretched as a result of this hanging method.


Author(s):  
Gertruida L. van Wyk ◽  
Louwrens C. Hoffman ◽  
Phillip E. Strydom ◽  
Lorinda Frylinck

Meat tenderness, water holding capacity (WHC) and colour attributes of six muscles (Longissimus thoracis et lumborum (LTL), Semimembranosus (SM), Biceps femoris (BF), Supraspinatus (SS), Infraspinatus (IS), Semitendinosus (ST)) from large frame Indigenous Veld Goats (IVG) and Boer Goats (BG) were studied. Weaner male Boer Goats (BG; n = 18; 10 bucks and 8 wethers) and large frame Indigenous Veld Goats (IVG; n = 19; 9 bucks and 10 wethers) were raised on hay and natural grass, and on a commercial pelleted diet to a live weight of 30 - 35 kg. All goats were slaughtered at a commercial abattoir and the dressed carcasses chilled at 4&deg;C within 1-hour post-mortem. The muscles were dissected from both sides 24-hours post-mortem and aged for 1-day and 4-days. Variations in meat characteristics such as ultimate pH, WHC, percentage purge, myofibril fragment length, intramuscular fat, connective tissue characteristics, and Warner-Bratzler shear force. Bucks had higher L* and Hue-angle values, whereas wethers had increased a* and Chroma values. The muscle baseline-data will allow informed decisions to support muscle-specific marketing strategies, which may be used to improve consumer acceptability of chevon.


2016 ◽  
Vol 266 ◽  
pp. e64-e67 ◽  
Author(s):  
Siobhan McLaughlin ◽  
Kirsten Kind ◽  
Lynne Thomson ◽  
Ralph Bouhaidar

Foods ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 215 ◽  
Author(s):  
Jacob R. Tuell ◽  
Jun-Young Park ◽  
Weichao Wang ◽  
Bruce Cooper ◽  
Tiago Sobreira ◽  
...  

The objective of this study was to evaluate the effects of photoperiod on meat quality, oxidative stability, and metabolites of broiler fillet (M. Pectoralis major) muscles. A total of 432 broilers was split among 4 photoperiod treatments [hours light(L):dark(D)]: 20L:4D, 18L:6D, 16L:8D, and 12L:12D. At 42 days, a total of 48 broilers (12 broilers/treatment) was randomly selected and harvested. At 1 day postmortem, fillet muscles were dissected and displayed for 7 days. No considerable impacts of photoperiods on general carcass and meat quality attributes, such as carcass weight, yield, pH, water-holding capacity, and shear force, were found (p > 0.05). However, color and oxidative stability were influenced by the photoperiod, where muscles from 20L:4D appeared lighter and more discolored, coupled with higher lipid oxidation (p < 0.05) and protein denaturation (p = 0.058) compared to 12L:12D. The UPLC–MS metabolomics identified that 20 metabolites were different between the 20L:4D and 12L:12D groups, and 15 were tentatively identified. In general, lower aromatic amino acids/dipeptides, and higher oxidized glutathione and guanine/methylated guanosine were observed in 20L:4D. These results suggest that a photoperiod would result in no considerable impact on initial meat quality, but extended photoperiods might negatively impact oxidative stability through an alteration of the muscle metabolites.


Foods ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 181
Author(s):  
Carlos Álvarez ◽  
Leonard Koolman ◽  
Michael Whelan ◽  
Aidan Moloney

Tenderness, together with flavour, is the main quality trait that defines consumer acceptance of sheep meat. The factors affecting tenderness can be grouped as those influenced before slaughter, in the early post-mortem intervention and, finally, during the aging period. These factors have been extensively studied with respect to tenderness, but the impact of early post-mortem interventions and subsequent aging on the microbial quality of the final products has not been broadly reviewed to date. In this review, the authors summarize the most recent knowledge on lamb meat tenderness management and how such practices may impact the final meat quality, especially its microbial status. The impacts of pre-slaughter factors (age, sex, diet, genotype and transport) and post-mortem interventions (chilling regime, electrical stimulation, or hanging method), are described and comprehensively discussed.


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