Impact of broiler carcass orientation after slaughter on breast meat quality when evaluating delayed processing

Authors: HARRIS, CAITLIN - Oak Ridge Institute For Science And Education (ORISE); CHOI, JANGHAN - Oak Ridge Institute For Science And Education (ORISE); SHAKERI, MAJID - Oak Ridge Institute For Science And Education (ORISE); Kong, Byungwhi; KIEPPER, BRIAN - University Of Georgia; Buhr, Richard - Jeff; Zhuang, Hong; Bowker, Brian

Submitted to: American Meat Science Association Conference Reciprocal Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/2024
Publication Date: 6/17/2024
Citation: Harris, C., Choi, J., Shakeri, M., Kong, B.C., Kiepper, B., Zhuang, H., Buhr, R.J., Bowker, B.C. 2024. Impact of broiler carcass orientation after slaughter on breast meat quality when evaluating delayed processing. American Meat Science Association Conference Reciprocal Proceedings. Abstract 88.

Interpretive Summary:

Technical Abstract: Objectives: With the standard practices for poultry harvesting, there is the potential for handling and transport conditions to impact bird welfare and meat quality negatively. In prior experiments simulating an alternative processing procedure in which birds are slaughtered on-farm and carcasses transported to the plant to continue processing, a notable effect on meat quality was the reddish discoloration on the cranial end of the raw breast fillets (pectoralis major). In the delayed processing experiments, the carcasses were held upside-down by their shanks on shackles. It is theorized that gravity caused residual blood in the carcasses to pool in the cranial end of the breast muscles, causing discoloration. Therefore, the objective of this trial is to determine if, during the delay post-slaughter, holding the carcasses either on their back or hanging them from the shackle by their neck prior to scalding and de-feathering will reduce discoloration. Materials and Methods: In total, 120 Cobb, 500 male broilers were selected for 4 treatments (n=30): Control (no delay), 4hr delay + held by shanks (4S), 4hr delay + held by neck (4N), or 4hr delay + held on back (4B). After electrical shock and bleed-out, carcasses in the Control group were hard-scalded and picked, as standard, while the 3 delay treatments were held for 4hr before scalding/picking. Post-pick, breast fillets from carcasses, were hot-deboned and chilled overnight. All fillets were scored on a scale of 1-3 for woody breast, white stripping, petechial hemorrhaging, and discoloration (cranial, caudal, and lateral). Individual fillets from each carcass were utilized for pH (before cooking), color (L*a*b*) measurements( before and after cooking), marination uptake (after marination), and Blunt Meullenet-Owens Razor shear force measurements (after cooking). Data were analyzed using JMP Pro 17.0.0 with parametric data analyzed with ANOVA and non-parametric data analyzed with the Kruskal–Wallis test. Results: Scores for petechial hemorrhaging and discoloration on cranial end of fillets were significantly higher (p=0.0134 and p<0.0001, respectively) for the 4S treatment compared to Control. Similarly, the discoloration score on the caudal end of fillets for 4N treatment was significantly higher than Control (p<0.0001), and discoloration on lateral side of 4B treatment fillets was significantly higher than Control (p<0.0001). The discoloration score results were supported by a* values for the raw fillets, with 4S fillets having significantly higher (p=0.0290) values than 4N fillets, with Control and 4B fillet values being intermediate. After marination, the raw fillets from 4S treatment still had the significantly highest (p=0.0247) a* values. After cooking the unmarinated fillets, Control treatment had significantly higher (p=0.0329) a* values compared to the 4B fillets, with 4S and 4N being intermediate. After the marinated fillets were cooked, there were no differences in a* values between the treatments. There were no significant differences between treatments for woody breast scores, white striping scores, cook loss, marination uptake, or tenderness. Conclusion: Results from this study support the conclusion that gravity caused residual blood to pool in the cranial end of the breast fillets, as holding the carcasses in different orientations during the 4 hr delay did impact the discoloration scores and a* values of the fillets.