Alternative methods of pig chilling

Abstract

Comparisons were made of the effect on cooling rate, weight loss, texture, bacterial numbers, drip and appearance of pork sides (average dead weight 75 kg) in refrigeration systems using high humidity (ice bank) or conventional chilling, both with and without a rapid pre-chill or delayed chilling, with and without a water spray. All treatments took between 15·7 and 19h post mortem to cool the deep leg of sides to 7°C. Weight loss varied between 0·95% for sides in the delay and spray treatment to 2·17% for conventional chilling. The texture of the M. longissimus dorsi of sides from the rapid pre-chill and conventional chilling treatment was significantly tougher than from the other methods, including those from the rapid pre-chill and high humidity system. Variation in texture between animals within treatments was far greater than between treatments, and could not be explained by variations in cooling and glycolytic rate. There were no significant differences ( P > 0·05) in bacterial numbers, drip and appearance between treatments. The choice of chilling system can be made on the basis of weight loss and capital and running costs. The delay and spray treatment would save £37 800 on an annual throughout of 3 080 tonnes of pork compared with a conventional system.