Effect of microclimate temperature during transportation of broiler chickens on quality of the pectoralis major muscle

This study investigated the effect of microclimate temperature during preslaughter transportation on chicken meat quality. Ninety broilers per load of 2,900 were monitored individually during 3 to 4 h of preslaughter transport in an actively ventilated trailer. Six transport test runs were conducted at average ambient temperatures of -27, -22, -17, -5, +4, and +11 degrees C. Birds were classified into 4 groups based upon the temperatures recorded in their immediate surroundings as follows: -16 to 0, 0 to 10, 10 to 20, and 20 to 30 degrees C. Internal body temperatures of the birds were recorded using Thermocron DS1922L iButtons. Birds were slaughtered in a commercial facility and meat quality of the chilled carcasses was evaluated by determination of pH, color, drip loss, thaw loss, cook loss, shear force, water-binding capacity, and pellet cook yield of the pectoralis major muscle. The breast meat from birds exposed to temperatures below 0 degrees C showed a significantly higher (P < 0.05) ultimate pH. Breast meat from birds exposed to temperatures below 0 degrees C showed significantly higher (P < 0.05) ultimate pH, a* value, water-binding capacity, and pellet cook yield and a significantly lower L* compared with breast meat of birds exposed to temperatures above 0 degrees C. The average core body temperatures were significantly lower (P < 0.05) during transport for birds exposed to temperatures below 0 degrees C compared with those exposed to temperatures between 0 and 10 degrees C. The latter birds had significantly lower (P < 0.05) core body temperatures compared with those exposed to temperatures above 10 degrees C. Thaw loss was significantly higher (P < 0.05) for breast meat of birds exposed to temperatures above 20 degrees C during transportation. There was no significant trend for b* value, drip loss, cook loss, or shear values based on environment temperature immediately surrounding the birds. Exposure to temperatures below 0 degrees C increased the incidence of dark, firm, and dry breast meat and decreased the incidence of pale, soft, and exudative breast meat. These results demonstrate that preslaughter transport may influence breast meat quality characteristics of broiler chicken.