When stress turns into economic losses

Does pre-slaughter stress affect meat quality? Science has the answer

Scientific studies confirm that heat stress and physiological stress prior to slaughter negatively impact meat quality (color, pH, texture, tenderness, water-holding capacity, shelf life, and overall poultry health). However, there is no conclusive scientific evidence showing that stress-related chemical mediators present in muscle and viscera directly affect human consumer health.

Research focuses on the following aspects:

Meat quality
Acute or chronic stress before slaughter depletes glycogen reserves, leading to abnormal meat pH levels (either too low, resulting in pale, soft, and exudative meat - PSE; or too high, resulting in dark, firm, and dry meat - DFD), which affects texture and appearance.

Animal health
Stress compromises the bird’s immune system and intestinal integrity, making it more susceptible to pathogens such as Salmonella and Campylobacter. These pathogens are the leading causes of foodborne illness in humans associated with the consumption and handling of contaminated poultry meat, representing the main risk to the consumer.

Chemical compounds during cooking
Some studies investigate the formation of potentially carcinogenic compounds (such as heterocyclic amines) when chicken meat is cooked at high temperatures, regardless of the stress experienced by the animal.

In summary
The main health risk to consumers associated with meat from stressed birds does not come from stress hormones or chemical mediators such as cortisol, which breaks down or is present in insignificant levels, but rather from a potential increase in bacterial contamination due to a compromised immune system and changes in meat quality that may affect shelf life.

Good management practices during pre-slaughter, slaughter, and post-slaughter stages, as well as an adequate distribution chain and proper meat cooking, are essential to ensure food safety.