3. The Impact of Ante- and Post-Mortem Factors on the Incidence of Pork Defective Meat – A Review

The occurrence of defective meat depends on factors affecting meat quality at the various stages of meat production. Defective meat has a broad definition and includes any property of meat that will dissatisfy end-users. For consumers the main meat quality features are colour, taste and texture (tenderness and juiciness). For processors and butchers very important are technological quality features: water holding capacity, pH, content of connective tissue, fat and protein. The functionality of defective meat is limited. The risk of incidence of defective meat is a result of the combination of ante-mortem and post-mortem factors. The ante-mortem factors are linked with the procedure at the lairage, the slaughtering factors, such as the method of stunning, and the post-mortem factors, including processing of meat carcasses. The ante-mortem factors such as genotype, gender, breeding conditions, nutrition, transport conditions, stress, weather conditions and the methods of slaughter are considered of primary importance for the quality of pork. It is estimated that 40% of meat defects are due to the procedure at the lairage. The impact of stressors causes a loss of weight of the pigs, contributes, in extreme cases, to the death of porkers, increases the risk of incidence of defective meat. Mixing animals from different herds is the cause of stress which leads to aggression and fights between animals. Limiting the stress factors is essential for improving the quality of pork. The applied stunning method affects the quality of meat. Physical stress during electrical stunning is associated with risk of an accelerated post-mortem glycolysis, contributing to the rapid decrease in pH. In comparison with the electrical method, stunning with carbon dioxide causes less stress in swine. In order to reduce the occurrence of defective meat, bleeding should be carried out as soon as possible directly after stunning. Deterioration of the quality of meat in the production chain can occur at any stage and is most often associated with the lack of compliance with the standards. The studies on the improvement of livestock breeding, transport and marketing carried out over a number of years contributed to the introduction of international standards and, consequently, to the reduction of quality and quantity losses in pork.