豚肉の品質向上を目的としたと殺システムの検討

Abstract

Systems for moving pigs from their holding place to the electric stunning space in a slaughter house were investigated in relation to the resultant meat quality. In the restrainer system, pigs got excited and early rigor mortis, which suggested the development of physiologically abnormal meat (PSE and DFD), developed in 4.3% of carcasses. Temperature of the carcasses was higher and the pH decreased rapidly. The quantity of blood which remained in muscles of the carcasses was higher than that obtained when pigs were stunned by striking their forehead while at rest. In the floor conveyor system, pigs were stunned quietly and early rigor mortis developed in only 0.7% of the carcasses. The temperature of these carcasses was relatively low and the pH decreased gradually. The blood quantity in muscles of the carcasses was lower than in the restrainer system. In the revolving round table system, the carcasses showed a lower incidence of early rigor mortis and a smaller quantities of blood in muscles, when compared with the results of the restrainer system. In experimental CO2gas stunning, the muscles relaxed and the blood quantity in the muscles was rather low. However, lactate levels in the blood and muscles were high, and the pH of the carcasses decreased rapidly. On the basis of the results obtained, it was suggested that the floor conveyor system was superior to the restrainer system. The CO2gas stunning system should be investigated further, as it way further enhance the production of good quality meat.