Influence of dietary lysine level, pre-slaughter fasting, and rendement napole genotype on fresh pork quality.

Sixty-four gilts from a commercial hybrid line were selected based on rendement napole (RN) genotype and live weight to evaluate the effects of feeding a lysine-deficient diet and feed withdrawal prior to slaughter on fresh pork quality. Glycolytic potential was measured and the bimodal distribution was utilized to predict RN genotype. Diets containing 4.8 (deficient) or 6.4 g/kg lysine were fed for the last six weeks prior to slaughter. Feed withdrawal treatments were imposed 12 or 36 h prior to slaughter. The lysine-deficient diet increased intramuscular fat content; however, feed withdrawal did not consistently impact fresh pork quality. Pork from RN carriers had a lower ultimate pH and Hunter L(*). Results from this study suggest that feeding a lysine-deficient diet can increase the intramuscular fat content of both RN genotypes, but feed withdrawal did not impact pork quality.

Creatine monohydrate supplementation and the quality of fresh pork in normal and halothane carrier pigs.

The objective of this research was to examine the impact of supplementation with creatine monohydrate (CMH) on the quality of various muscles from normal and heterozygous halothane carrier pigs. Twenty-nine crossbred pigs, 16 normal (NN) and 13 halothane carrier (Nn) genotypes, were supplemented with 0 or 25 g x pig(-1) x d(-1) of CMH for 5 d before slaughter. Supplemented pigs gained 2.26 kg more weight (P < 0.05) during 5 d of supplementation. There were trends (P < 0.10) toward higher objective marbling scores and lower cooking loss for supplemented pigs. The 45-min pH was 0.27 units higher (P < 0.05) for supplemented pigs in the semimembranosus; CMH supplementation did not influence (P > 0.05) drip loss or muscle composition. Supplementation with CMH also resulted in lower L* values in two ham muscles, semitendinosus (5.15 units) (P < 0.05) and semimembranosus (1.95 units) (P < 0.10) for Nn carcasses. Genotype had significant effects on most quality indicators, with Nn carcasses producing lower-quality lean as evidenced by less desirable subjective and objective color and higher drip losses. Genotype also affected the composition of several muscles, with the NN carcasses having more fat and less moisture.

Factors influencing consumer demand for U.S. pork exported to the Republic of Korea (South Korea).

The potential market for single-ribbed bellies and Boston butts in South Korea was characterized and quantitative selection criteria were identified for use by U.S. packers when selecting pork for export. South Korean retail meat market managers and traders/wholesalers in Seoul and Pusan were interviewed and asked to identify the quality attributes that are considered when making pork-purchasing decisions. In addition, pork labeling characteristics and meat display case measurements and space allocations were recorded in each retail store. Data from box labels were recorded in retail storage coolers to characterize pork products currently being merchandized in South Korea. Sample retail packages of belly and butt slices were collected and sent to a commercial laboratory for analysis of iodine values, ether-extractable fat content, total aerobic plate count (APC), total coliform count (TCC), and generic Escherichia coli count (ECC). No quality attributes of U.S. products exceeded the expectations of retailers. Quality attributes of U.S. pork products that exceeded the expectations of traders included presence of foreign material, marbling, tenderness, juiciness, flavor, and overall eating satisfaction. Traders/wholesalers assigned negative ratings for overall workmanship and adherence to purchase criteria for U.S. pork products. Retail APC for South Korean belly samples were higher (P < 0.05) than APC for U.S. belly samples. Retail TCC and ECC for butts and belly samples and APC for butt samples did not differ by country of origin. Retail prices for South Korean bellies were higher (P < 0.05) than prices for retail U.S. and Danish bellies. Pork butt prices did not differ (P > 0.05) by country of origin. Beef, pork, and poultry products comprised 66.8, 27.8, and 5.4%, respectively, of the total meat display case frontage. U.S. beef products occupied, on average, 18% of the total beef display area, whereas U.S. pork products comprised 2.6% of the total pork display case area.

Quantification of pork belly and boston butt quality attribute preferences of South Korean customers.

U.S. packers must have quantitative criteria for selection of pork bellies and Boston butts for export to South Korea. Pork bellies (IMPS 409A) and Boston butts (IMPS 409A, 406B, 407) were selected from normal production in a U.S. pork packing plant and transported to Seoul, South Korea, via seafreighter in refrigerated containers (frozen < -5 degrees C) or via air freight (fresh > 0 degrees C; frozen < -5 degrees C). Participants at the Seoul Food Show were surveyed about their preferences for specific quality attributes of these cuts. Bellies were selected to differ in seam fat content (low = < 20%, moderate = 20 to 40%, high = > 40% extractable fat), lean color (pale = L* > 50, medium = L* 48-50, dark = L* < 48), weight (3.36, 4.04, or 5.36 kg), state of refrigeration and packaging (frozen, poly-wrapped; chilled, poly-wrapped; frozen, vacuum-packaged; chilled, vacuum-packaged), shape (round, wavy, square), and belly thickness (3.81, 4.32, or 4.90 cm). Boston butts were selected to differ in USDA marbling score (Slight, Small, Modest, Moderate, and Slightly Abundant), seam fat content (low = < 10%, moderate = 10 to 20% fat, high = > 20% extractable fat), lean color (pale = L* > 44, medium = L* 40-42, dark = L* < 38), weight (2.91, 3.82, or 4.66 kg), state of refrigeration and packaging (frozen, poly-wrapped; chilled, poly-wrapped; frozen, vacuum-packaged; chilled, vacuum-packaged), and shape (square, oblong, round). In Seoul, pork subprimals were tempered (if frozen), sliced, and arrayed by quality attribute and category in a retail display case. Over 4 d of testing, attendees (n = 210) of the food show were asked to rate the displayed samples for each quality attribute on a standardized ballot. Mid-weight (3.82 kg) Boston butts that displayed Moderate or higher USDA marbling scores with moderate amounts of seam fat, Japanese lean color scores of 2 or 4, round geometric shape, and that were vacuum-packaged and transported to Korea in the freshly chilled state best characterized the quality attribute preferences of respondents. Pork bellies that exhibited moderate amounts of seam fat, Japanese lean color scores of 3, square shape, belly thickness of 3.94 cm, approximate weight of 4.04 kg, and that were vacuum-packaged and transported to Korea in the freshly chilled state best met the quality needs of South Korean customers.

Frequency of the Rendement Napole RN- allele in a population of American Hampshire pigs.

A total of 204 purebred Hampshire pigs were obtained from 23 breeders. These animals were the progeny of 41 sires and 123 dams. A sample of purebred Yorkshire (n = 24) pigs were also used in the study. Animals were classified by glycolytic potential determined on a live-animal longissimus muscle biopsy sample. Hampshire pigs (n = 176) with glycolytic potential greater than 185 micromol/g (x = 238.8 micromol/g; SD = 29.54) were classified as heterozygous or homozygous for the dominant RN- allele (RN-rn+ or RN-RN-, respectively), whereas cohorts (n = 28) with glycolytic potential less than 185 micromol/g (x = 141.3 micromol/g; SD = 24.48) were considered as homozygous normal (rn+rn+). All Yorkshire pigs (n = 24) had a mean glycolytic potential level of 146.1 micromol/g (SD = 20.18) and were considered as homozygous normal (rn+rn+). The Hardy-Weinberg equilibrium yielded frequencies of .630 and .370 for the dominant RN- allele and normal rn+ alleles in the Hampshire population, respectively, and genotypic frequencies of .397 (RN-RN-), .466 (RN-rn+), and .137 (rn+rn+). Hampshires with glycolytic potential > or = 185 micromol/g had significantly lower longissimus muscle ultimate pH, intramuscular fat, subjective marbling scores, and percentage of protein (P < .001) and had greater longissimus muscle percentage of moisture (P < .001), drip loss (P < .01), and cooking loss (P < .001) than rn+rn+ Hampshires and Yorkshires. These data suggest the RN- allele exists at a high frequency within the American Hampshire breed. Higher glycolytic potential levels, which accompany the allele, may cause decreased meat quality.