Market pigs (n = 120) were rested 0, 1, 2, or 3 h before slaughter. One carcass side was hot-fat trimmed (HFT) immediately after dressing, and the other was not fat trimmed (NFT). Sides received conventional chilling (CC) or accelerated chilling (AC) in a freezer at -32 degrees C for 100 min. Skin temperatures of live pigs decreased 5 degrees C during 3 h of rest, and resting reduced muscle temperature at .5 and 1.5 h postmortem. Early postmortem muscle pH was .3 higher if pigs were rested up to 2 h if CC was used (P < .01). Resting pigs 2 h decreased loin purge about 1% and increased cured ham yields 6% over those not rested. The AC carcasses had about .15 higher muscle pH from 4.5 to 24 h postmortem than CC carcasses (P < .03). The AC improved loin quality about 15% and lowered L values of loins and hams about 4% (P < .04). The AC substantially reduced the incidence of unacceptable quality in loins and hams, with the most effect on hams, and slightly toughened loin muscles but not cured ham muscles. Resting of pigs and AC of carcasses gave superior color of loin chops at d 0 of retail display and lowered L values during display. The HFT process improved ham quality scores about 8% but not loin scores. Resting pigs for 2 h, AC, and HFT in concert or separately are effective means of improving pork quality; AC had by far the greatest effect.

The effects of chilling (normal chill or freeze chill) and trimming (hot fat trim or no fat trim) on the microbial populations of pork carcases were evaluated. In a two-part study, composited ham, loin, belly, and shoulder samples from 30 park carcasses had similar aerobic plate counts, averaging 5.5 log10 CFU/cm2. The nofat trim, normal chill procedure typically used in the industry, however, produced higher coliform and Staphylococcus spp. counts (P < 0.05). The hot fat trim, freeze chill treatment had the lowest lactic acid bacteria counts. Only 1 sample in 60 tested positive for Salmonella spp. Vacuum-packaged hams and loins stored at 4 degrees C for 14 days had similar (P > 0.05) aerobic plate counts, lactic acid bacteria and Staphylococcus spp. counts regardless of trim, chill, or the location of treatment, averaging 5.7, 6.3 and 1.4 log10 CFU/cm2, respectively. Hams had higher counts than loins all three days; however, only the difference on day 2 was significant. The desire to reduce microbial populations on pork carcasses as a food-safety issue and the coming implementation of hazard analysis critical control points (HACCP) programs warrants the use of trimming and chilling methods as critical control points or good manufacturing practices and standard operating procedures in the pork slaughter, processing, and packaging industry.

The objective of our study was to explore relationships between Japanese color score (JCS) and pork-quality attributes and develop equations to predict JCS. Pork carcass traits in population one (n = 781) was used to develop prediction equations and population two (n = 684) was used to test the equations for accuracy. Pearson's correlation coefficients found firmness, ultimate pH, drip loss percentage, L*, a*, b*, hue angle, and chroma were significantly (P < 0.01) correlated to JCS. Correlation loading found 96% of the variation in firmness, pH, drip loss percentage, L*, a*, b*, and hue angle explained 81% of the variation in JCS. Three prediction equations were developed using these traits. Averages for population one traits were used to develop the initial prediction equations. Predicted JCS, which fell within ±0.25 of the actual JCS, were retained and multiple linear regression (MLR) was run, resulting in the first prediction equations. Data from population two were then used to evaluate the success of these equations. of the actual JCS, respectively. All prediction equations predicted 92% or more of the JCS observations within ±0.50 and would be useful when sorting pork carcasses for export to valuable Asian markets. The second and third prediction equations would be advantageous as they require fewer measurements and could be more rapidly collected.

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Food safety concerns know no global boundaries. Information is disseminated daily, and even hourly via Internet, which describes concerns ranging from E. coli 0157:H7 in American beef to Listeria monocytogenes in Greek feta cheese. According to the CDC website (2002), an estimated 1.4 million cases of salmonellosis occur annually in the United States with an estimated 500 or more fatal cases each year. Although these numbers are rather staggering, Hedberg (2001) indicated that pork or pork containing foods were implicated as the source for only 3% of salmonellosis outbreaks reported by CDC from 1990-97. Sarwari et al. (2001) indicated that serotypes impacting human illness may not correlate as well as expected to those found in animals. There remains the question of variable virulence between types of Salmonella spp., which might cause one to reconsider treating all Salmonella as equals. Investigations into virulence of specific strains of Listeria monocytogenes and Campylobacter are being conducted as well.