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

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

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

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

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

The Effect of Cooking Method and Cooked Color on Consumer Acceptability of Boneless Pork Chops

The objective was to determine the effects of sous-vide cooking and degree of doneness on consumer eating experience of pork chops when cooked color was expected to differ. The hypothesis was consumers would prefer a cooked brown color and would rate grilled chops more acceptable than sous-vide chops. Chops were cooked to 63 &deg;C or 71 &deg;C using either an open-hearth grill or a sous-vide device. Participants evaluated four samples for tenderness, juiciness, flavor, and overall acceptability. Participants rated a greater percentage of chops cooked sous-vide at 63 &deg;C as tender (82.82%), juicy (55.83%) and acceptable (60.34%) compared with all other cooking method and degree of doneness combinations. Participants rated a greater percentage of sous-vide chops as tender and acceptable compared to grilled chops. Participants rated a greater percentage of chops cooked to 63 &deg;C as tender, juicy, flavorful, and acceptable when compared to 71 &deg;C. Even when participants could visualize cooked color, they preferred chops cooked to 63 &deg;C compared with chops cooked to 71 &deg;C. Overall, participants preferred chops cooked to 63 &deg;C compared to 71 &deg;C regardless of the cooking method and preferred chops cooked to 63 &deg;C using the sous-vide cooking method the most among all treatments

Effect of Salt Inclusion Level on Commercial Bacon Processing and Slicing Yields

The objectives were to determine effects of salt inclusion on production yields, commercial slicing yields, sensory characteristics, and lipid oxidation of bacon. A total of 144 bellies that ranged in weight from 5.8 to 6.6 kg were selected from 2 different suppliers. Fresh bellies were weighed to determine an initial weight (green weight). Then, bellies were randomly assigned to salt levels of 1.2, 1.5, or 1.8% in the final product and manufactured into bacon. Bacon was stored frozen, in aerobic packages, for approximately 0 d, 30 d, 60 d, or 90 d and analyzed for lipid oxidation. Sensory analysis was conducted approximately 14 d after slicing and again 90 d later. Cook yield was increased ( ≤ 0.05) in 1.2% bacon compared with 1.5 and 1.8% bacon, but slicing yield was 1% unit greater ( ≤ 0.05) in 1.8% bacon compared with 1.2% bacon. Increasing salt content from 1.5 to 1.8% increased the number of bacon slices generated from a slab of bacon by 12 slices and by nearly 16 slices when compared with the 1.2% treatment. Sensory saltiness increased ( ≤ 0.05) as intended salt level increased. Lipid oxidation and oxidized odor and flavor intensity was not different among salt treatment levels within any storage period. Reducing salt from 1.8 to 1.2% in bacon can adversely affect slicing yield, but was not detrimental to cook yield and did not reduce the rate of lipid oxidation of bacon