Pork loin quality is not indicative of fresh belly or fresh and cured ham quality

Authors: ARKFELD, E.K. - University Of Illinois; WILSON, K.B. - University Of Illinois; OVERHOLT, M.F. - University Of Illinois; HARSH, B.N. - University Of Illinois; LOWELL, J.E. - University Of Illinois; HOGAN, E.K. - University Of Illinois; KLEHM, B.J. - University Of Illinois; BOHRER, B.M. - University Of Illinois; MOHRHAUSER, D.A. - Smithfield Foods, Inc; King, David - Andy; Wheeler, Tommy; DILGER, A.C. - University Of Illinois; Shackelford, Steven; BOLER, D.D - University Of Illinois

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/2016
Publication Date: 12/29/2016
Citation: Arkfeld, E.K., Wilson, K.B., Overholt, M.F., Harsh, B.N., Lowell, J.E., Hogan, E.K., Klehm, B.J., Bohrer, B.M., Mohrhauser, D.A., King, D.A., Wheeler, T.L., Dilger, A.C., Shackelford, S.D., Boler, D. 2016. Pork loin quality is not indicative of fresh belly or fresh and cured ham quality. Journal of Animal Science. 94:5155-5167. doi:10.2527/jas2016-0886.

Interpretive Summary: There is increasing interest in implementing a U.S. pork quality grading system. The loin is often used as the indicator of carcass quality but hams and bellies provide a substantial portion of carcass value and little data on their quality exists. In order to develop an effective quality grading system a better understanding of the relationships among the carcass primal cuts is needed. Results indicate loin quality explained a low amount of variability in belly and ham quality traits. Differences in composition and chilling rates of the different primal cuts contributed to the low relationships among the primal cuts. Loin quality traits are not good indicators of ham and belly quality.

Technical Abstract: The objective was to characterize the relationship between fresh 30 loin quality and with fresh belly or fresh and cured ham quality. Pigs raised in 8 barns representing two seasons [cold (n = 4,290) and hot (n = 3,394)] and two production focuses [lean (n = 3,627) and quality n = 4,057)] were used. Carcass characteristics and other meat quality data were collected on 7,684 carcasses. All of the carcasses were evaluated for HCW, LM depth, 10th 34 rib fat depth, leg ham primal) weight, instrumental color on the gluteus medius and gluteus profundus of the ham face, and subjective loin quality. Instrumental loin color and ultimate pH (= 22 h postmortem were collected on the ventral side of loins along with dimensions and firmness scores of fresh bellies from 50% of the carcasses. Ten percent of the boneless loins and fresh hams were evaluated for slice shear force (SSF) or cured ham characteristics. Correlation coefficients between traits were computed using the CORR procedure of SAS and considered significantly different from 0 at P = 0.05. Temperature decline, beginning at 31 min postmortem and concluding at 22 h postmortem, for the longissimus dorsi and semimembranosus muscles were evaluated on 10% of the carcasses. Ultimate loin pH was correlated with dimensional belly Characteristics (r = |0.07|; P < 0.0001) fresh ham instrumental color (r = |0.03|; P = 0.05), and semimembranosus ultimate pH (r = 0.33; P < 0.0001). Further, ultimate loin pH was correlated (P = 0.01) with pump retention (r = 0.087) and cooked yield (r = 0.156) of cured hams. Instrumental L*on the ventral surface of the loin was related to L* on both muscles of the ham face (P = 0.0001). Even though significant relationships between the loin, belly, and ham were detected, the variability in belly and ham quality explained by variability in loin quality was poor (= 22.09%). Compositional differences between the loin and belly may have contributed to those poor relationships. Additionally, differences in temperature declines during chilling between the loin and ham likely contributed to the weak nature of relationships. Equilibration of longissimus dorsi temperature to ambient cooler temperature occurred at 14 h postmortem (P = 0.0005), yet the semimembranosus had not equilibrated with ambient (equilibration bay) temperature (P < 55 0.0001) at 22 h postmortem. Using loin quality to draw conclusions about fresh belly and fresh and cured ham quality may be misleading.