16 research outputs found

    Correlation Comparisons of Early and Aged Quality Traits of Pork Aged Either as Intact Loins or Case-Ready Chops

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    Approximately half of retail pork chops in the U.S. arrive at the store in case-ready packages. The other half arrives as intact-loins and are sliced when needed. Cutting chops from loins may increase moisture loss leading to lighter colored and less juicy meat. Therefore, it is possible that correlations between loin quality traits observed early postmortem (PM) and aged quality traits would differ between intact-loin aged (ILA) chops and case-ready aged (CRA) chops. Loins (288 total) were selected to fill a matrix that varied in visual color and marbling. Loins were assigned to 1 of 2 packaging treatments (n = 144): ILA or CRA. Loins assigned as ILA remained vacuum-packaged at 4°C until 12 d PM, sliced and chop surface was evaluated. Loins assigned to CRA were sliced into 28-mm thick chops at 2 d PM, packaged in individual Styrofoam trays overwrapped in polyvinyl-chloride (PVC) film, and gas flushed in bulk packages. Quality parameters of packaging treatments at early and aged time points were compared as a randomized complete block design. Pearson correlation coefficients between early and aged quality traits for packaging treatments were transformed using Fisher’s r to z transformation for independent correlation comparisons of packaging treatments. Chops from ILA were darker and redder at 12 d PM than CRA chops (P < 0.0001). Lightness and redness values on ventral surface for ILA loins (r = 0.52 lightness; r = 0.63 redness) and CRA loins (r = 0.45 lightness; r = 0.61 redness) at 1 d PM were both correlated with aged lightness and redness values on aged chop face at 12 d PM and the correlations did not differ (P ≄ 0.43) for either trait. Overall, aging intact loins in vacuum-packaging improved color after 12 d of aging compared with aging chops in case-ready packaging. Despite the differences between aging methods, the correlations between early and aged loin quality didn’t differ

    Evaluation of Muscle Fiber Characteristics Based on Muscle Fiber Volume in Porcine Longissimus Muscle in Relation to Pork Quality

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    In livestock science and meat science, muscle fiber characteristics have been evaluated based on a cross-sectional area (CSA) of muscle fiber. However, muscle fiber is not planar but cylindrical. Thus, muscle fiber volume and volume-based characteristics were evaluated in this study. In addition, their relationships to pork loin quality was assessed and compared with that of CSA-based muscle fiber characteristics. Muscle fiber type IIB was underestimated by CSA-based evaluations with 1.6 times in fiber size and 2.6 times in relative composition. The pennation angle, which ranged from 48.00° to 83.33°, determined the real CSA and total number of fibers (TNF) on the surface of a loin chop. Significant (P < 0.05) correlation coefficients were found: fiber volume (r = –0.37) and volume % (r = –0.37) of type IIX with loin length; volume % of type IIX with CIE L* (r = 0.40); volume % of types IIX (r = 0.39) and IIB (r = –0.39) with Warner-Bratzler shear force. Although those correlations to loin quality differed from those of CSA-based characteristics, the Z-scores did not show any significance between the 2 correlation coefficients, except for TNF. Therefore, the conventional methodology for muscle fiber characteristics can be used for evaluating the relationship to pork quality; however, the new methodology is more useful in estimating the characteristics of muscle fiber, which is elongated and cylindrical and to correct the underestimated fiber size and composition of type IIB

    Characterizing Ham and Loin Quality as Hot Carcass Weight Increases to an Average of 119 Kilograms

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    The objective was to characterize ham and loin quality of carcasses ranging from 78 to 145 kg (average ∌119 kg). Hot carcass weight (HCW), back fat depth, and loin depth was measured on 666 carcasses. Loin pH, instrumental and visual color and iodine value of clear plate fat (all 3 layers) was measured on approximately 90% of the population. Quality measurements of the ham, 14 d aged loin and chop, and loin chop shear force (SSF) were evaluated on approximately 30% of the population. Myosin heavy chain fiber type determination was completed on 49 carcasses. Slopes of regression lines and coefficients of determination between HCW and quality traits were calculated using the REG procedure in SAS and considered significantly different from 0 at P ≀ 0.05. As HCW increased, loin depth (b1 = 0.2496, P 0.15) and did not explain more than 1% (R2 ≀ 0.01) of the variation in 1 d loin color or pH. Loins from heavier carcasses were more tender (decreased SSF; b1 = –0.0674, P 0.22) muscle fiber type percentage or area. These results suggest that increasing HCW to an average of 119 kg did not compromise pork quality

    Effects of Increased Pork Hot Carcass Weights. I: Chop Thickness Impact on Consumer Visual Ratings

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    The objective of this study was to evaluate the effect of increased pork hot carcass weights on consumer visual acceptability and purchase intent ratings of top loin chops cut to various thicknesses in a price labeled versus unlabeled retail display scenario. Pork loins (N = 200) were collected from 4 different hot carcass weight groups: light weight (LT; less than 111.8 kg), medium-light weight (MLT; 111.8 to 119. kg), medium-heavy weight (MHVY; 119.1 to 124.4 kg), and a heavy weight group (HVY; 124.4 kg and greater). Loins were fabricated into 4 pairs of chops of specified thicknesses (1.27, 1.91, 2.54, and 3.18 cm). One chop from each pair was assigned to be packaged with or without a label. Consumers assessed chops for appearance, desirability, and purchase intent. For both appearance and purchase intent ratings, chops from HVY carcasses were given more desirable (P < 0.05) ratings compared to LT chops. Consumers gave greater (P < 0.05) appearance ratings to thicker cut chops. There was a hot carcass weight × chop thickness interaction (P < 0.05) for the percentage of consumers that indicated the chop was desirable overall. Regardless of hot carcass weight group, chops with a thickness of 1.27 cm had the lowest (P < 0.05) percentage of consumers indicate they were desirable overall. A greater (P < 0.05) percentage of consumers indicated “yes” they would purchase chops cut to a thickness of 2.54 cm compared to all other thicknesses. Additionally, there was a greater (P < 0.05) percentage of consumers who indicated they would purchase unlabeled chops compared to labeled chops. These results, within the population sampled, indicate that carcass weight and chop thickness can affect consumer preference and thus should be considered by retailers when marketing fresh pork loin chops

    Effects of Increased Pork Hot Carcass Weights. II: Loin Quality Characteristics and Palatability Ratings

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    The objective of this study was to evaluate the effects of increased pork hot carcass weight on loin quality and palatability of top loin chops. Pork loins (N = 200) were collected from 4 different hot carcass weight groups: A light weight (LT; less than 111.8 kg), medium-light weight (MLT; 111.8 to 119.1 kg), medium-heavy weight (MHVY; 119.1 to 124.4), and a heavyweight group (HVY; 124.4 and greater). Following fabrication, chops were assigned to fat and moisture analysis, Warner-Bratzler shear force (WBSF), consumer sensory panels, or trained sensory panels. Chops from the HVY group were rated as more (P 0.05) consumer flavor liking ratings. Hot carcass weight treatment did not contribute (P > 0.05) to the percentage of chops rated acceptable for flavor and overall liking. The greatest (P 0.05), with greater (P < 0.05) overall tenderness ratings compared to chops from LT carcasses. These results indicate chops from heavier weight carcasses may have improved tenderness and juiciness compared to chops from lighter carcasses

    Effects of gonadotropin releasing factor immunological (Improvest??) on carcass characteristics, pork quality, and further processing characteristics of finishing male pigs

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    The objective of the research was to evaluate a new technology used to suppress testicular function of male pigs using an immunological designed to block the communication of gonadotropin releasing factor (GnRF) with the anterior pituitary gland. This disrupts the production of a number of male sex hormones such as testosterone and androstenone. The reduction of testosterone allows for an increase in hepatic metabolism of skatole. Androstenone and skatole are the two primary compounds associated with objectionable odors and aromas collectively known as "boar taint". Boar taint issues are the one of the key reasons physical castration (surgical castration) has been so widely adopted in United State swine production systems. Improvest?? (Pfizer Animal Health, Kalamazoo, MI) is a 9 amino-acid base pair GnRF conjugate that prevents boar taint in entire male pigs even when allowed to grow to ending live weights over 130 kg. This research used two populations of pigs of PIC genetics (Pig Improvement Company, Hendersonville, TN) divided over three independent experiments. The objectives of the first experiment were to determine if increasing lysine levels in the diets of immunologically castrated (IC) male pigs will increase percent fat free lean and carcass cutability. The objective of the second experiment was to determine if increasing lysine levels in the diets of IC male pigs will affect further processed product characteristics when compared to physical castrates or entire males. Raw materials for this experiment were derived from the same pigs used in the previous experiment evaluating carcass characteristics and cutability. The objectives of the final experiment were to determine if advantages in cutting yields of immunocastrated (IC) males over physical castrates, demonstrated in the first experiment, would persist when pigs were harvested at either 4 weeks (early harvest group) or 6 weeks (late harvest group) post second injection and to evaluate belly quality and bacon processing characteristics of IC males fed a moderate level of dietary unsaturated fatty acids (DDGS). In the first experiment, 96 pigs (16 per treatment) were selected based on ending live weight (weight 48 h prior to harvest) for further analysis. The experiment used four dietary programs differing in percent lysine inclusion where the diets ranged in a low lysine level (0.7% in the late finishing diet) to a high lysine level (1.0% in the late finishing diet). Percent fat-free lean increased 3.7 percentage units in IC males as lysine level was increased from low (56.1% fat-free lean) to high (59.8% fat-free lean) dietary lysine. There were no differences (P > 0.05) among IC males fed low, low/medium, or medium/high lysine levels, but there was a linear increase (P = 0.01) in fat-free lean as dietary lysine level increased. There were no differences in shear force, cook loss, or ultimate pH (P ??? 0.05) among any of the treatment groups. Extractable lipid of loin chops decreased 1.01 percentage units from IC males fed the low lysine diet (2.29%) to the IC males fed the high lysine diet (1.28%). Lean cutting yields and carcass cutting yields were higher in IC males than in physical castrates, but were lower than entire males. There was a linear increase in lean cutting yield (P = 0.05) and carcass cutting yield (P = 0.01) in IC males as dietary lysine level increased. Entire males (2.85 cm) had the thinnest (P 0.05) among physical castrates or IC males regardless of lysine level. There were no differences (P ??? 0.05) in protein content or protein fat-free values in cured and smoked hams among any treatment group. A total of 156 pigs (78 IC males and 78 physical castrates) were used in the second population of pigs. Selection criteria were based on sex and ending live weight where the heaviest 15 pigs within a pen were selected at 4 weeks post-second injection and the remaining 10 pigs in the pen were selected at 6 weeks post second injection. Pigs were harvested at either 4 or 6 weeks post-second injection and within each harvest group pigs were classified as heavy, light, or median weight. There were no differences between IC males and physical castrates for shear force (P = 0.09), ultimate pH (P = 0.57), L* (P = 0.93), a* (P = 0.33), b* (P = 0.31), subjective color score (P = 0.64), or drip loss (P = 0.30). There were no interactions between sex and harvest time (P = 0.99) or between sex and weight category (P = 0.43) or the three-way interaction (P = 0.84) for lean cutting yields. There were also no interactions between sex and harvest time (P = 0.49) or between sex and weight category (P = 0.66) or the three-way interaction (P = 0.28) for carcass cutting yields. Lean cutting yields of IC males (28.84 kg) were 1.20 kg heavier, 2.62 percentage units higher (P < 0.0001), than physical castrates (27.64 kg) and carcass cutting yields were 1.06 kg heavier, 2.27 percentage units higher (P < 0001), for IC males (33.98 kg) when compared to physical castrates (32.91 kg). Bellies from IC males were thinner (P = 0.01) and had wider belly flops (P < 0.0001) than bellies from IC males. Even though cook loss percentage was greater (P < 0.0001) in IC males when compared to physical castrates, cooked yields were not different (P = 0.74) between the two sexes. Over both populations of pigs, immunological castration with Improvest?? does not affect pork quality, improves cutting yields, makes fresh bellies thinner, but does not affect cured product characteristics

    Relationship between Inherent Cooking Rate and Warner-Bratzler Shear Force of Pork Chops Cooked to Two Degrees of Doneness

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    The objective was to test inherent cooking rate differences on tenderness values of boneless pork chops when exogenous factors known to influence cooking rate were controlled. Temperature and elapsed time were monitored during cooking for all chops. Cooking rate was calculated as the change in &deg;C per minute of cooking time. Warner-Bratzler shear force (WBSF) was measured on chops cooked to either 63 &deg;C or 71 &deg;C. Slopes of regression lines and coefficients of determination between cooking rate and tenderness values for both degrees of doneness (DoD) were calculated. Shear force values decreased as cooking rate increased regardless of DoD (p &le; 0.05), however changes in tenderness due to increased cooking rate were limited (&beta;1 = &minus;0.201 for 63 &deg;C; &beta;1 = &minus;0.217 for 71 &deg;C). Cooking rate only explained 3.2% and 5.4% of variability in WBSF of chops cooked to 63 &deg;C and 71 &deg;C, respectively. Cooking loss explained the most variability in WBSF regardless of DoD (partial R2 = 0.09&ndash;0.12). When all factors were considered, a stepwise regression model explained 20% of WBSF variability of chops cooked to 63 &deg;C and was moderately predictive of WBSF (model R2 = 0.34) for chops cooked to 71 &deg;C. Overall, cooking rate had minimal effect on pork chop tenderness

    Non-Destructive Luminescence-Based Screening Tool for Listeria monocytogenes Growth on Ham

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    Listeria monocytogenes is a food-borne pathogen often associated with ready-to-eat (RTE) food products. Many antimicrobial compounds have been evaluated in RTE meats. However, the search for optimum antimicrobial treatments is ongoing. The present study developed a rapid, non-destructive preliminary screening tool for large-scale evaluation of antimicrobials utilizing a bioluminescent L. monocytogenes with a model meat system. Miniature hams were produced, surface treated with antimicrobials nisin (at 0&ndash;100 ppm) and potassium lactate sodium diacetate (at 0&ndash;3.5%) and inoculated with bioluminescent L. monocytogenes. A strong correlation (r = 0.91) was found between log scale relative light units (log RLU, ranging from 0.00 to 3.35) read directly from the ham surface and endpoint enumeration on selective agar (log colony forming units (CFU)/g, ranging from 4.7 to 8.3) when the hams were inoculated with 6 log CFU/g, treated with antimicrobials, and L. monocytogenes were allowed to grow over a 12 d refrigerated shelf life at 4 &deg;C. Then, a threshold of 1 log RLU emitted from a ham surface was determined to separate antimicrobial treatments that allowed more than 2 log CFU/g growth of L. monocytogenes (from 6 log CFU/g inoculation to 8 log CFU/g after 12 d). The proposed threshold was utilized in a luminescent screening of antimicrobials with days-to-detect growth monitoring of luminescent L. monocytogenes. Significantly different (p &lt; 0.05) plate counts were found in antimicrobial treated hams that had reached a 1 log RLU increase (8.1&ndash;8.5 log(CFU/g)) and the hams that did not reach the proposed light threshold (5.3&ndash;7.5 log(CFU/g)). This confirms the potential use of the proposed light threshold as a qualitative tool to screen antimicrobials with less than or greater than a 2 log CFU/g increase. This screening tool can be used to prioritize novel antimicrobials targeting L. monocytogenes, alone or in combination, for future validation

    Characteristics of Ham Knuckles and Bacon Cured Using Different Brine and Meat Temperatures

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    Three experiments were conducted to evaluate the effect of brine and meat temperature on the processing characteristics of pork knuckle hams and bacon. Experiment 1 used 111 pork knuckles tempered to 4°C, randomly allotted to 1 of 3 in-going brine temperatures; 1) –1°C (Cold), 2) 7.2°C (Medium), or 3) 15°C (Warm). Experiment 2 used 59 hams, randomly allotted to 1 of 3 brine temperatures similar to Experiment 1 but meat was tempered to match brine temperature resulting in treatments of: 1) Cold/Cold, 2) Medium/Medium, and 3) Warm/Warm. Experiment 3 used the same treatments as Experiment 1, but applied to bellies ( = 60). Experiments 1 and 3 were analyzed as randomized complete block designs and Experiment 2 was analyzed as a completely randomized design. In Experiment 1, there was no effect ( ≄ 0.32) of brine temperature on processing traits, but L* of warm-brine hams were 1.2 units greater ( = 0.02) than cold-brine hams, but not different ( = 0.19) than medium-brine. Cold-brine hams tended ( = 0.07) to have greater a* than warm-brine hams. In Experiment 2, drained-brine-uptake of Warm/Warm and Medium/Medium hams were 14 and 10% units greater ( < 0.0001) than Cold/Cold hams, resulting in 9.09 and 10.65% units greater ( < 0.0001) overall yield. Warm/Warm and Medium/Medium hams had greater moisture content ( < 0.01) and tended to have reduced ( = 0.10) L* than Cold/Cold hams, but did not differ ( = 0.18) a*. In Experiment 3, brine temperature had no effect ( ≄ 0.14) on any bacon processing trait, composition, or sensory traits. Overall, brine temperature alone had minimal effects on ham or bacon processing traits, but in combination with meat temperature, may influence processing yields and product quality
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