INFLUENCE OF LAIRAGE ENVIRONMENTAL-CONDITIONS AND RESTING TIME ON MEAT QUALITY IN PIGS

This study investigated the influence of lairage environmental conditi ons and resting time on pig carcasses and meat quality. The experiment al material consisted of 1001 cross Pietrain-Duroc-HampshirexBelgium-L R-LW pigs, held in lairage for either approximate to 30 min (direct sl aughter) or between 2-3 h under 12 degrees C/90% relative humidity (RH ), 20 degrees C/80% or 90% RH and 35 degrees C/50% or 85% RH. Prior to arrival at the lairage plant they were transported for about 45-60 mi n and subjected to a fasting period of 36 h before loading. Unloading operation and the driving of pigs to the point of stunning were carrie d out according to the practices used in the plant (sticks and electri cal goods were used). Batches of 20-30 mixed pigs were used in each tr ial, held at a stocking density of approximately 0.55 m(2)/pig (approx imate to 100 Kg live weight). Lairage environmental conditions (LC), s ignificantly affected almost all measurements, but not pH(1), in Semi- membranosus (SM) and Longissimus dorsi (LD) muscles and the carcass da mage score. The influence of resting time (RT) was basically exerted o n pH(u), deep ham temperature and in pH(1), of SM, the internal muscle reflectance being mostly unaffected There were also significant batch (B) effects in a large range of parameters. Factors greatly interacte d their influence on carcass and meat quality, denoting LCxB, LCxRTxB and LCxRT the most significant effects. RTxB only showed two low signi ficant interactions for rigor value and pH(1), in SM, suggesting that, conversely to the lairage environmental conditions the influence of r esting time is practically unaffected by the day of slaughter. The inc rease of lairage temperature decreased the frequency of nor mal carcas ses, followed by an expressive higher incidence of PSE status. The inf luence of lairage relative humidity on the PSE/DFD muscle incidence de pended on the associated temperature, but the most important detriment al effects were noticed in experiments carried out at 35 degrees C. In respect to lairage resting time, the influence on meat quality is str ictly related to environmental conditions, mainly the temperature. Nev ertheless, and excepting the assays at 35 degrees C/85% RH, direct sla ughter of pigs (=30 min in pens) generally produced less carcasses of normal quality than vesting periods up to 2-3 h. (C) 1997 Elsevier Sci ence Ltd.