Factors affecting the pH decline in lamb after slaughter

Area of Science:

• Meat Science
• Animal Science
• Food Science

Background:

• Early postmortem pH is a critical factor influencing meat tenderness, particularly in processing methods like electrical stimulation and rapid chilling.
• Understanding factors affecting early postmortem pH is essential for optimizing meat quality and predicting tenderness outcomes.

Purpose of the Study:

• To investigate the influence of various factors, including season, age, and sex, on early postmortem pH decline in lamb meat.
• To develop predictive models for 4-hour postmortem pH using early pH measurements and carcass traits.

Main Methods:

• A 12-month trial involving 96 lambs, recording carcass traits (age, sex, weight).
• Measurement of M. longissimus thoracis et lumborum pH at 0.5, 1.5, 4, and 24 hours postmortem.
• Regression analysis to compare combined and sex-specific models for predicting 4-hour pH.

Main Results:

• Significant seasonal variations in pH were observed over 12 months, but not attributable to season or age.
• Animal sex did not affect early (0.5, 1.5 h) or final (24 h) pH, but 4-hour pH was significantly lower in females (P<0.001).
• Sex-specific regression models (R(2)=0.80) provided better prediction of 4-hour pH than a combined model (R(2)=0.74).

Conclusions:

• Early postmortem pH in lamb is influenced by factors beyond season and age, with sex playing a role at 4 hours.
• Sex-specific prediction models for 4-hour pH offer improved accuracy in lamb carcass assessment.
• These findings aid in understanding and managing factors affecting meat quality and tenderness in lamb production.