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Biomedical subjects

M F Miller

Publications and source records attributed to M F Miller.

At least 37 records · Page 2Linked to original sources
PubMed2002

Alternative housing systems for pigs: influences on growth, composition, and pork quality.

Effects of pig birth (first 3-wk period) and rearing environments on growth and muscle quality characteristics of loins were evaluated in three experiments over seasons in west Texas and central Missouri. Housing systems included indoor slatted-floor buildings, indoor deep-bedded buildings, outdoor housing on dirt, and outdoor housing on alfalfa pasture. Experiments were conducted during the growing/finishing phases and pigs were slaughtered at the same age. Loins were collected, vacuum-packaged, and stored for 14 d at 2 degrees C. Pigs born and finished in an outdoor environment during the summer months (Exp. 1) had a greater ADG (0.92 vs 0.82+/-0.06 kg/d, P < 0.05) and had heavier carcass weights (87.9 vs 78.4+/-2.4 kg, P < 0.05) than pigs born and finished in an indoor environment with a slatted-floor finishing building. Carcasses from the outdoor-reared group measured a larger (P < 0.05) loineye area and were fatter (P < 0.01) at the first rib, last rib, and last lumbar vertebra measurements than carcasses from the indoor-reared group. Loin chops from outdoor-reared pigs had darker color scores in the retail display case throughout the 4-d period, measured lower L* values on d 1, and had more discoloration and browning on d 4 than loin chops from the indoor-reared group. During the winter months (Exp. 2), no difference was detected in ADG, carcass measurements, sensory characteristics, or shear force values from indoor-born pigs placed in either an outdoor or indoor finishing environment. Pigs finished on deep bedding (Exp. 3) had heavier carcass weights and more backfat (P < 0.01) than pigs finished on slats, but no differences were detected in sensory panel or shear force results. Overall, carcass measurements, pH, drip loss, sensory panel, and shear force values were similar among the groups finished in different housing systems. Outdoor or deep-bedded systems may increase growth rates of pigs if suitable land area and resources are available, but pork quality of loins will be similar for pigs finished in either conventional or alternative systems.

Animal Husbandry↗
PubMed2002

Shear gradient in longissimus steaks.

Boneless top loin subprimals (n = 320) from Slight and Small marbled carcasses were fabricated into 2.54-cm thick steaks to determine core location effects on tenderness. In Exp. 1, top loins were aged to 7 d before steaks were cut and cooked to an internal temperature of 71 degrees C. After cooking, a maximum of 15 1.27-cm diameter cores were removed and sheared with a Warner-Bratzler shear force (WBSF) device. There was not a marbling score x core location interaction (P = 0.36). However, there was a main effect of core location (P < 0.01). Cores from the medial, middle, and lateral portion of the longissimus muscle (LM) aged for 7 d differed, with less resistance (P < 0.05) in the medial than the lateral end. Also, there was an effect of marbling score on WBSF, with Small-marbled steaks having lower (P < 0.02) WBSF values than Slight-marbled steaks. In a second experiment, steaks were removed from the middle of the top loin subprimals and aged an additional 7 d to produce 14-d aged steaks. Shear values decreased (P < 0.05) from Exp. 1 to 2 for all core locations. Neither the main effect of marbling score nor the core location x marbling score interaction was significant (P > 0.40); however, the same lateral to medial gradient in WBSF values was discovered again in Exp. 2. Both experiments indicated there were regions of WBSF values that differed (P < 0.05) across the cross section of the LM producing a shear-force/tenderness gradient, with the most medial cores having the lowest WBSF values in both experiments independent of marbling score. Regression analyses indicated the middle and center portions of LM steaks tended to have the most predictive capacity of average WBSF. Because of the variability in tenderness caused by location within the LM, care should be exercised when selecting sampling areas for the measurements of tenderness using the WBSF measure.

Aging↗
PubMed2002

Effects of the transportation of beef cattle from the feedyard to the packing plant on prevalence levels of Escherichia coli O157 and Salmonella spp.

Two hundred steers and heifers from a large feedyard (65,000-head capacity) were used to determine the prevalence levels of enterohemorrhagic Escherichia coli O157 (EHEC O157) and Salmonella spp. prior to and after shipping to a commercial packing facility. Two samples, a ventral midline hide swab and a fecal sample, were aseptically collected from each animal 2 weeks prior to the date of transportation and at the packing plant immediately after exsanguination. Samples were collected from all trailers (n = 46) before animals were loaded for transport to the packing facility. The average prevalence levels of EHEC O157 on hides (18%) and in feces (9.5%) at the feedyard decreased (P > 0.05) at the packing plant to 4.5 and 5.5%, respectively. The average prevalence levels of Salmonella spp. on hides (6%) and in feces (18%) at the feedyard increased to 89 and 46%, respectively, upon arrival at the packing plant. Average prevalence levels for EHEC O157 and Salmonella spp. on the trailers were 5.43 and 59%, respectively. The results of this study demonstrate that transportation may be a potential stressor for cattle, as evidenced by the increased shedding of Salmonella spp.

Animals↗
PubMed2001

The current practice of intra-aortic balloon counterpulsation: results from the Benchmark Registry.

OBJECTIVES: This study presents clinical data from the first large registry of aortic counterpulsation, a computerized database that incorporates prospectively gathered data on indications for intra-aortic balloon counterpulsation (IABP) use, patient demographics, concomitant medication and in-hospital outcomes and complications. BACKGROUND: The intra-aortic balloon pump (IABP) is widely used to provide circulatory support for patients experiencing hemodynamic instability due to myocardial infarction, cardiogenic shock, or in very high risk patients undergoing angioplasty or coronary artery bypass grafting. METHODS: Between June 1996 and August 2000, 203 hospitals worldwide (90% U.S., 10% non-U.S.) collected 16,909 patient case records (68.8% men, 31.2% women; mean age 65.9 +/- 11.7 years). RESULTS: The most frequent indications for use of IABP were as follows: to provide hemodynamic support during or after cardiac catheterization (20.6%), cardiogenic shock (18.8%), weaning from cardiopulmonary bypass (16.1%), preoperative use in high risk patients (13.0%) and refractory unstable angina (12.3%). Major IABP complications (major limb ischemia, severe bleeding, balloon leak, death directly due to IABP insertion or failure) occurred in 2.6% of cases; in-hospital mortality was 21.2% (11.6% with the balloon in place). Female gender, high age and peripheral vascular disease were independent predictors of a serious complication. CONCLUSIONS: This registry provides a useful tool for monitoring the evolving practice of IABP. In the modern-day practice of IABP, complication rates are generally low, although in-hospital mortality remains high. There is an increased risk of major complications in women, older patients and patients with peripheral vascular disease.

Age Factors↗
PubMed2001

Consumer thresholds for establishing the value of beef tenderness.

In the present study, a national consumer evaluation was conducted for beef tenderness on USDA Select strip loin steaks of known Warner-Bratzler shear (WBS) force values, ranging from tough (> 5.7 kg) to tender (< 3.0 kg), and to assess the monetary value that consumers place on tenderness by determining the average price a consumer would pay for a steak in three tenderness categories. Three supermarkets in each of five metropolitan areas (Baltimore, MD/Washington D.C.; Chicago, IL; Dallas/Fort Worth, TX; Los Angeles, CA; and Lubbock, TX) were selected to represent a wide range of income, education, and ethnicity at each city. Five trained research teams traveled to the cities to collect data during the same 10-d period. Consumers (n = 734; minimum of 15 consumers/panel, three panels/store, three stores/city, five cities) were asked to evaluate samples from each tenderness classification (tender, intermediate, or tough) for overall and tenderness acceptability, overall quality, beef flavor, juiciness, tenderness, how much they would pay for the steak ($17.14, 14.28, or 10.98/kg), if they would pay more than current market price if guaranteed tender, and to estimate the number of meals in a 2-wk period that included beef. The consumers were 52% light beef users, consuming 0 to 8 meals containing beef in 2 wk, 41% heavy beef users (greater than 12 meals/2 wk), and 6% moderate beef users (9 to 12 meals/2 wk). Consumer tenderness acceptability increased as WBS values decreased (P < 0.05). The transition in consumer perception from tender to tough beef occurred between 4.3 and 4.9 kg of WBS based on > or = 86% consumer acceptability. Consumer acceptability for tenderness decreased from 86% at 4.3 kg for a "slightly tender" rating to 59% at 4.9 kg for a "slightly tough" rating. Data from the present study suggested that consumer WBS tenderness values of < 3.0, 3.4, 4.0, 4.3, and > 4.9 kg would result in 100, 99, 94, 86, and 25% customer satisfaction for beef tenderness, respectively. Seventy-eight percent of the consumers would purchase steaks if the retailer guaranteed them to be tender. The retail steak value differences found in this study would result in the opportunity for a premium to be paid for a guaranteed tender (< 3.0 kg WBS value) carcass of $76.26 vs the toughest (> 5.7 kg) classification. A premium of $66.96 could be paid to the tender classification carcasses vs the tough (> 4.9 kg) classification carcasses, and a premium of $36.58 could be paid for the tender classification carcasses vs the intermediate (> 3.0 to < 4.6 kg) classification carcasses. Results from the present study show that consumers can segregate differences in beef tenderness and that consumers are willing to pay more for more-tender beef.

Animals↗
PubMed2001

Tasco-Forage: III. Influence of a seaweed extract on performance, monocyte immune cell response, and carcass characteristics in feedlot-finished steers.

Tall fescue (Festuca arundinacea Schreb.) infected with the endophyte Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon, and Hanlin) causes fescue toxicosis in cattle grazing the forage, but effects of the endophyte were considered to be abated soon after removal of the animals from pastures. Tasco-Forage, a proprietary extract from the brown seaweed Ascophyllum nodosum, is a known source of cytokinins and has increased antioxidant activity in both plants and the animals that graze the forage. Tasco was applied at 0 and 3.4 kg/ha to infected and uninfected tall fescue pastures in Virginia and Mississippi. Forty-eight steers grazed the pastures at each location during each of 2 yr (n = 192) before being transported to Texas for feedlot finishing. On arrival at the feedlot, steers from Tasco-treated pastures had higher (P < 0.01) monocyte phagocytic activity and tended (P < 0.07) to have higher major histocompatibility complex class II expression than steers that grazed the untreated pastures. A depression (P < 0.05) in monocyte immune cell function due to grazing infected fescue was detected throughout the feedlot finishing period but was reversed by Tasco. Rectal temperatures were elevated (P < 0.07) in steers that had grazed the infected tall fescue when they arrived in Texas, but by d 14 no difference was detected. However, by d 28 the temperature effects of infected tall fescue were reversed. Steers that had grazed infected fescue had lower (P < 0.01) rectal temperatures on d 112 of the feedlot period, demonstrating a much longer-lasting effect of the endophyte on thermoregulatory mechanisms than previously thought. Steers that had grazed Tasco-treated pastures had higher (P < 0.01) rectal temperatures on d 56 than steers that had grazed untreated fescue. Steers that had grazed the Tasco-treated pastures had higher marbling scores (P < 0.05) regardless of the endophyte, but no effect of Tasco or endophyte on gain was measured. Our data suggest that Tasco application to tall fescue pastures alleviated some of the negative effects of tall fescue toxicity.

Animal Feed↗
PubMed2001

Tasco-Forage: IV. Influence of a seaweed extract applied to tall fescue pastures on sensory characteristics, shelf-life, and vitamin E status in feedlot-finished steers.

Tasco-Forage is an Ascophyllum nodosum seaweed-based product that has increased antioxidant activity in both plants and animals. Endophyte (Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon, and Hanlin)-infected and uninfected tall fescue (Festuca arundinacea Schreb.) pastures in Virginia and Mississippi during 1997 were treated or not with 3.4 kg Tasco/ha in April and July. There were two replications of each treatment at each location. Forty-eight steers (6/replication) grazed pastures at each location (n = 96) from April to October prior to transportation to Texas Tech, Lubbock, for finishing during a 160-d period in the feedlot. Blood (antemortem) and liver (postmortem) samples were collected. After slaughter and chilling, the left strip loins (IMPS #180) were collected from three randomly selected steers from within each pasture replication (n = 48). Strip loins were vacuum-packaged and stored at 2 degrees C. At postmortem d 7, 14, 21, and 28, strip loins were removed from packaging and fabricated into 2.54-cm steaks. Following each fabrication day postmortem, the strip loins were repackaged and stored at 2 degrees C until the following postmortem time. After the prescribed fabrication, steaks were overwrapped with polyvinyl chloride film, subjected to simulated retail display at 2 degrees C for up to 3 d, and subjective and objective color were evaluated daily by a trained panel. Steaks from Mississippi steers that had grazed Tasco-treated fescue retained higher (P < 0.05) CIE a* color scores throughout retail display. Steaks were more uniform and had less discoloration and less browning (P < 0.05) if they were from steers that had grazed Tasco-treated fescue, and the effect was greatest for steers from Mississippi (location x Tasco interaction; P < 0.05). The endophyte in tall fescue may decrease uniformity and increase lean discoloration and two-toning of beef steaks when removed from vacuum packaging on or beyond d 21 postmortem (endophyte x Tasco x postmortem day interaction: P < 0.05). Vitamin E in liver was increased (P < 0.06) and serum vitamin E was decreased (P < 0.09) in steers that had grazed the treated pastures. These experiments indicated that Tasco applied to tall fescue during the grazing season can improve color stability and extend beef shelf-life, particularly in cattle grazing infected tall fescue. The mode of action of Tasco is not clear, but antioxidants and specific vitamins may be involved.

Aging↗
PubMed2001

Shade and water misting effects on behavior, physiology, performance, and carcass traits of heat-stressed feedlot cattle.

One hundred twelve crossbred feedlot heifers were used in two experiments to assess the impact of heat stress and its relief by shade and(or) water misting on behavior, physiology, performance, and carcass traits. Treatments were 1) no shading or misting (CONT); 2) only misting (MIST); 3) only shading (SHADE); and 4) shading plus misting (SHMI). Head in the feed bunk, head in or above the waterer, walking, standing, and lying behaviors were observed. Rectal temperature, respiration rate, and carcass traits were measured, as well as DMI, ADG, and feed:gain. Dietary NEm and NEg concentrations were calculated from performance data. In Exp. 1, (32 heifers; average BW 288 kg) the CONT heifers spent more time lying down than all others (P < 0.01). In addition, CONT heifers spent less time (P < 0.01) standing than SHADE and MIST heifers. Misting decreased (P < 0.01) rectal temperature and MIST as well as SHADE lowered (P < 0.05) respiration rates. In Exp. 2 (80 heifers; average BW = 336 kg), lying and walking behaviors did not differ among treatments, but shade increased (P < 0.01) standing behavior in heifers. The MIST cattle performed less (P < 0.05) head-above-water behavior than unmisted cattle. Rectal temperatures did not differ among treatments, but respiration rate was lower in shaded than in unshaded heifers (P < 0.05). Shaded compared with unshaded heifers had greater DMI (9.46 vs 8.80 +/- 0.14 kg/d, P < 0.01) and ADG (1.6 vs 1.41 +/- 0.1 kg/d, P < 0.01). Heifers provided with shade reached their target BW 20 d earlier than the unshaded heifers and differed in final BW (547 vs 520 +/- 6 kg, P < 0.01). Feed:gain and calculated NEg and NEm concentrations did not differ among treatments, and carcass traits were generally similar among treatments. In conclusion, cattle without shade had a physiological and behavioral stress response to heat that negatively affected productivity. Providing shade for beef cattle was a suitable solution to decrease heat stress and to lower the negative effects of heat on performance, whereas misting was largely ineffective.

Animal Husbandry↗
PubMed2001

Vitamin-mineral supplementation and accelerated chilling effects on quality of pork from pigs that are monomutant or noncarriers of the halothane gene.

We examined the effects of vitamin and mineral supplementation of the finishing diet on growth and accelerated chilling of carcasses on carcass and muscle traits of halothane gene carrier and noncarrier pigs. Barrows and gilts that were either monomutants (MON, n = 49) or noncarriers (NON, n = 28) of the halothane gene were fed a standard finishing diet until they reached 86 kg. They then were randomly assigned to one of four finishing diets formulated to contain 11 IU/kg vitamin E (0), 311 IU/kg vitamin E plus additional vitamins and minerals (300), 611 IU/kg vitamin E plus additional vitamins and minerals (600), or 911 IU/kg vitamin E plus additional vitamins and minerals (900) until they were slaughtered (118 kg). Alternating carcass sides were assigned either a normal chilling procedure (NC, 4 degrees C for 24 h) or an accelerated chilling procedure (AC, -20 degrees C for 1.5 h and then 4 degrees C for 22.5 h). Supplementing vitamin E in the finishing diet increased (P < 0.05) the concentration of vitamin E in the longissimus muscle. Supplementing vitamin E in the diets of MON pigs did not affect color, firmness, or cooking losses of loins or color and firmness of hams. For the NON genotype, increasing the level of vitamin E in the diet decreased (P < 0.05) the percentage of PSE loins and hams. Color and firmness scores of the gluteus medius and longissimus muscles were improved 0.4 unit (P < 0.005) by AC compared with NC of carcasses. Loin chop juiciness and flavor were improved (P < 0.05) in the MON genotype for AC compared to NC. Accelerated chilling reduced (P < 0.05) the percentage of PSE loins from 38 to 17% and PSE hams from 32 to 10% for the MON genotype, but percentage of PSE was not affected (P > 0.05) by chilling treatment for the NON genotype. No interaction between diet and chill treatments existed for muscle quality traits (P > 0.05). Supplementing finishing diets of NON pigs with at least 600 IU/kg vitamin E, in addition to other vitamins and minerals, or accelerated chilling of MON carcasses can reduce the incidence of PSE pork.

Animals↗
PubMed2001

Pre-operative intra-aortic balloon counterpulsation in stable patients with left main coronary disease.

OBJECTIVE: To determine whether prophylactic, pre-operative, intra-aortic balloon counterpulsation (IABC) improves clinical outcome in stable patients with severe left main coronary artery disease. METHODS: A post-hoc analysis of 457 prospectively tracked, non-randomized patients undergoing coronary artery bypass graft surgery (CABG) for left main stenoses 50% and multivessel coronary disease, but without any hemodynamic compromise or ongoing angina, was conducted. Patients with heart failure, shock, ongoing ischemia or previous CABG were excluded. In 287 patients, pre-operative IABC was not used (Group 1), while IABC was initiated in 170 patients for "prophylaxis" (Group 2). RESULTS: Groups 1 and 2 were similar in age (67 +/- 10 years versus 67 +/- 11 years, respectively), sex (72% male versus 71% male, respectively), and body mass index (28 +/- 5.5 versus 27 +/- 5.1, respectively). However, more Group 1 patients had peripheral vascular disease (PVD) (25% versus 11%), but more Group 2 patients had diabetes (37% versus 29%), and a lower left ventricular ejection fraction. The unadjusted 30-day mortality was significantly higher in Group 1 [16 (5.6%) versus 2 (1.2%); p = 0.02]. Cardiopulmonary bypass time and post-operative length of stay did not differ between the two groups. After adjusting for PVD in the multivariate analysis, the p-value for the no IABP versus IABP comparison in the presence of PVD was 0.10, even though 0/18 patients with PVD and IABC died. CONCLUSION: While unadjusted mortality appears lower with prophylactic IABC, confounding variables such as PVD mandate a larger, randomized clinical trial in order to establish the role of IABC in stable patients with left main disease.

Age Factors↗
PubMed1999

Accuracy of application of USDA beef quality and yield grades using the traditional system and the proposed seven-grade yield grade system.

Beef carcasses (n = 5,542) were evaluated by three USDA on-line graders and compared with the computed expert USDA quality (QG) and yield grades (YG) during 8-h shifts at a major beef-processing facility for a 2-wk period to evaluate the accuracy of applying USDA QG and YG within the traditional five-grade and the proposed seven-grade (segregating YG 2 and 3 into YG 2A, 2B, 3A, and 3B) YG systems. Quality grade distribution of the carcasses was 1.1% Prime, 50.0% Choice, 43.8% Select, and 5.1% No-Roll. Accuracy of applying QG was not affected (P>.05) by changing from the five-grade (91.5%) to either the seven-grade system, when determining only QG (94.3%), or the seven-grade system, when determining QG and YG (95.0%). Calculated expert YG successfully segregated carcasses into their respective YG, but on-line graders could not differentiate between YG 4 and 5 in the seven-grade systems. The application of YG in the five-grade system was more accurate (P<.05) than either of the seven-grade systems. A trend existed for on-line graders to undergrade carcasses as the numerical YG increased. Total accuracy of applying YG decreased by 19.4 to 21.8% when switching from the five-grade to the seven-grade system. The segmentation of USDA YG 2 and 3 into YG 2A, 2B, 3A, and 3B resulted in a decrease in the ability of on-line graders to accurately apply the YG.

Animals↗
PubMed1999

Electrical stimulation effects on tenderness of five muscles from Hampshire x Rambouillet crossbred lambs with the callipyge phenotype.

The objective of this study was to determine effects of electrical stimulation (ES) on muscle quality and sensory traits of 12 Hampshire x Rambouillet callipyge lambs. One side of each carcass was randomly assigned to an ES treatment of 550 V and 60 Hz of electricity for 2 s on and 2 s off 15 times. The other side was a nonstimulated control (NES). Heated calpastatin, sarcomere length, myofibrillar fragmentation index (MFI), Warner-Bratzler shear (WBS), and trained sensory panel values were measured on the semitendinosus (ST), semimembranosus (SM), longissimus (ML), supraspinatus (SP), and triceps brachii (TB) muscles. Electrically stimulating the carcass sides induced a more rapid (P = .001) pH decline in the longissimus muscle, and ES sides had a brighter (P = .001) red color of loineye than nonstimulated sides. At d 14 of storage (2 degrees C), the TB had the highest (P < .05) MFI value, indicating more protein degradation, and the ST and ML muscles had the lowest MFI (P = .008). Regardless of ES treatment, SM and ML had the highest (P < .05) WBS values. The ST muscle had higher (P < .05) WBS values than the SP but did not differ (P > .05) from the TB muscle. Electrical stimulation had no effect on WBS or any trained sensory panel values (P > .05). The percentage of loin chops rated slightly tender or better was improved 30 to 34% by electrical stimulation (P < .05). The ML muscle was scored lower (P < .05) in sustained juiciness compared with the SM, SP, and TB but did not differ (P > .05) from the ST muscle. The SM and ML muscles were rated lower (P < .05) in initial and sustained tenderness scores than other muscles. Tenderness scores were higher (P < .05) for the TB than for the SP but did not differ (P > .05) from the ST muscle. Electrically stimulating callipyge carcasses improves the tenderness of loin chops by increasing the percentage of chops rated from slightly tough to slightly tender.

Animals↗
PubMed1998

Feeding of a well-cooked beef diet containing a high heterocyclic amine content enhances colon and stomach carcinogenesis in 1,2-dimethylhydrazine-treated rats.

Epidemiologic studies have linked the consumption of red meat and the consumption of highly browned meats containing high levels of heterocyclic aromatic amines (HCAs) to increased risk of colorectal cancer or polyps. The present study determined the effects of long-term feeding of beef-containing diets with low and high levels of HCAs (in the context of a low or high beef tallow diet) on a standard 1,2-dimethylhydrazine (DMH)-induced colon tumorigenesis protocol. Very lean beef was cooked by a variety of methods at different temperatures, and the levels of the major HCAs (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline, and 2-amino-1-methyl-6-phenylimidazo[4,5-f]pyridine) were measured by high-performance liquid chromatography. Diets incorporating beef containing low or high levels of HCAs were fed for 12 weeks, during which DMH was administered to induce colon tumors, followed by various dietary regimens as promotional stimuli. Feeding of a beef diet high in HCAs resulted in more DMH-induced colon adenocarcinomas, but only in the context of a low-fat diet. The high-HCA diets increased stomach tumors in all DMH-treated rats. An apparent interaction of high HCA with a high fat level reduced the colon tumor incidence and tumor numbers in those diets containing both factors. These results support the epidemiologic data linking well-cooked meat to increased risk for colon and stomach cancer, but the role of dietary fat level remains puzzling.

1,2-Dimethylhydrazine↗
PubMed1998

Resting of pigs and hot-fat trimming and accelerated chilling of carcasses to improve pork quality.

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.

Animals↗
PubMed1998

Chilling and trimming effects on the microbial populations of pork carcasses.

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.

Abattoirs↗
PubMed1997

Non-promoting effects of iron from beef in the rat colon carcinogenesis model.

Significant alarm has existed among the general public in the past few years that eating red meat may cause human colon cancer. Iron in beef has been hypothesized as one of the factors in the etiology of this cancer. The present study was designed to test the hypothesis that dietary iron solely from beef would enhance colon tumorigenesis induced in rats. Tumors were induced in Sprague-Dawley rats with 1,2-dimethylhydrazine (20 mg/kg body weight for 10 weeks). Seventy male weanling rats were randomized to two dietary treatment groups with two iron sources (very lean beef vs. iron citrate) as the factor. The rats were allowed free access to the respective diet and deionized water for 27 weeks. At termination of the study, the rats were examined for location, size and type of colon or extracolonic lesions. No significant differences were found in total incidence and number of colon tumors between the beef (51.7%, 0.8 tumors/rat) and casein (62.1%, 0.9 tumors/rat) diets, although the serum iron levels of rats fed the beef diet were higher than for those fed the casein diet. The results demonstrate that, when lean beef is used as an iron source, the risk for colon carcinogenesis is not increased.

Adenocarcinoma↗