pH post-mortem on poultry carcasses in a slaughter line for industrial identification of PSE (Pale, Soft, Exudative) and normal meat [pdf]

Background. Some quality defects can cause changes in the attributes of meat, among which we can high-light PSE (Pale, Soft and Exudative) meats. PSE results from a sudden drop in pH while the carcass is still at an elevated temperature. The identification of PSE meat has previously been done through the measurement of pH and L* value (Luminosity). Studies suggest that a more accurate assessment of the kinetics of pH and temperature decrease needs to be conducted to better understand the etiology of PSE meat in poultry. The objective of this work was to obtain a glycolytic curve for normal meat and chicken PSE through the analysis of pH, L*, and WHC (Water holding capacity).Materials and methods. A glycolytic curve was obtained for normal meat and PSE through pH, L* and WHC. Samples of breast fillets were obtained from carcasses immediately after sampling from the chiller, and the pH, temperature, and L* were measured between the times of 1h35min and 25h35min postmortem (pm). The WHC analysis was performed at 25h35 pm.Results. As of 8h35 pm, the pH values of the meat were found to have stabilized, with the pH of the PSE meat being 5.69 +/- 0.07, and of the regular meat being 5.93 +/- 0.09. The final pH (25h35min pm) was 5.98 +/- 0.06 and the L* 57.30 +/- 2.39 for normal meat, while the result for the PSE meat was 5.72 +/- 0.06 for pH and 59.44 +/- 1.51 for L*. The WHC results showed a difference between the normal chicken fillets and PSE, which were 67.19 +/- 3.13 and 64.45 +/- 2.66 respectively. Conclusion. We conclude that under industrial conditions of slaughter, the resolution of rigor mortis occurs 8h35 pm.