Drivers of pork quality

Pigs are highly sensitive to stress during transport and handling before harvest. Factors such as loading conditions, lairage time, and handling methods can accelerate muscle metabolism and trigger a rapid decline in pH after slaughter. When this drop in pH occurs while the carcass temperature is still high, muscle proteins begin to break down, resulting in pale, soft, and exudative (PSE) pork.

Controlling temperature decline is one of the most effective ways to manage this risk. A faster chilling rate slows postmortem glycolysis, reducing the rate of pH decline and helping maintain color and water-holding capacity.

In commercial environments, these parameters are difficult to measure continuously. Most studies have relied on limited data collected at set intervals. PIC scientists used specialized equipment to capture pH and temperature readings every minute throughout the chilling process, creating a detailed picture of how carcasses respond to different cooling systems. This continuous data allowed for stronger modeling and a clearer understanding of the biological changes that influence final product quality.

Study design

The research evaluated 210 carcasses across four commercial facilities. Two plants used blast chilling, one used soft-blast chilling, and one used conventional chilling. Temperature and pH were measured continuously in the loin muscle for 20 hours postmortem, starting 40 minutes after slaughter. Loin quality was assessed 24 hours postmortem based on color, pH, firmness, marbling, and drip loss. Data were analyzed to identify time points and patterns that best predicted final product quality.

Key findings

Carcasses that consistently cooled faster produced higher-quality loins. Facilities using blast chilling showed a reduced rate and extent of pH decline (P < .05), resulting in darker color (P < .05) and less drip loss (P < .05). Conventional chilling, which allowed a slower temperature decline, was associated with faster pH decline and more drip loss.

The most accurate predictive model used pH values taken at 75, 300, and 360 minutes postmortem along with temperature data at 345 and 1,200 minutes. This model predicted 20-hour bone-in pH with a correlation coefficient of r = 0.94, demonstrating that early postmortem data can accurately forecast final product quality.

Moderate correlations were also found for predicting color and drip loss, showing that both traits are influenced by how quickly the carcass cools within the first several hours postmortem.

Applying the findings in the plant

These results provide practical insights for commercial processors who want to fine-tune chilling systems and reduce variation in product quality. By identifying specific time points in the temperature and pH decline curves, plants can target process adjustments where they have the most impact, optimizing air flow, carcass spacing and chilling duration to consistently achieve desired quality outcomes.

The research also highlights the potential for more data-driven process control. As sensor technology and automation continue to advance, early postmortem measurements could eventually be used for real-time carcass classification. This would enable processors to make immediate adjustments that protect meat quality and improve overall efficiency.

Integrating genetics and processing

This research builds on PIC’s broader focus on genetic improvement and carcass value realization. While genetics define the biological potential for meat quality, postharvest management determines how much of that potential is achieved.

Environmental factors such as chilling rate and handling practices often have a stronger influence on final meat quality than genetics alone. By measuring how temperature and pH interact during the chilling process, the study connects PIC’s genetic advancements to practical applications that help processors consistently deliver high-quality pork.

Industry Impact

While these models will require validation within individual plants, they represent a practical step toward predictive quality management. Each abattoir operates under unique conditions — such as chilling system design, carcass size and airflow — that influence cooling and pH patterns. Developing facility-specific models could further improve accuracy and allow processors to fine-tune their systems for optimal performance.

Understanding and controlling pH and temperature decline early in processing offers a new way to enhance meat quality and consistency across the supply chain. For processors and consumers alike, this approach helps ensure that every cut meets the standard of quality expected from modern pork production.

By Brandon Fields, McKenna Kent, Xuenan Chen, Bruno Valente, Neal Matthews, L. Clay Eastwood, Andrzej Sosnicki