Biomedical subjects

G C Smith

Publications and source records attributed to G C Smith.

At least 73 records · Page 4Linked to original sources

PubMed2001

Effects of gestational age and labor on expression of prostanoid receptor genes in baboon uterus.

We determined the effect of gestational age and labor on the regional expression of prostanoid receptor genes in baboon myometrium. Cesarean hysterectomy was performed on 15 pregnant baboons of known gestational age in the last third of pregnancy, five of them during spontaneous term labor. Expression of prostanoid receptor genes was studied using Northern blot analysis. Transcripts of similar size to the human were detected for prostanoid EP(1), EP(2), EP(3), EP(4), IP, FP, and TP receptor genes using Northern blot analysis. There were no gestational age-related changes in expression of these genes. Expression of EP(1), EP(3), and IP receptor RNA mRNA was significantly higher in myometrium from the fundus (compared with the lower segment), whereas EP(2) gene expression was significantly lower in the fundus. Labor was associated with a reduction in the regional variation of both EP(2) and IP receptor gene expression, but not EP(1) and EP(3) expression. Labor was also associated with an overall lower level of expression of EP(2) receptor mRNA. We conclude that regional and labor-related variation in myometrial expression of prostanoid receptor genes may have a key role in primate parturition.

Animals↗

PubMed2001

Effect of gestational age, corticosteroids, and birth on expression of prostanoid EP receptor genes in lamb and baboon ductus arteriosus.

The aim of this study was to determine the effect of corticosteroids, gestational age, and birth on the expression of genes encoding prostanoid receptors in the lamb and baboon ductus arteriosus. The ductus arteriosus was obtained from 34 lambs and eight baboons, including chronically instrumented fetuses of both species exposed to either corticosteroid or vehicle. Expression of prostanoid receptor genes was quantified using Northern blot analysis relative to each of two housekeeping genes. Expression of both the EP3 and EP4 receptor genes was detected in lamb ductus and the level of expression of both genes was unaffected by corticosteroids. Expression of the EP4 receptor gene was lower in the ductus obtained from term lambs compared with preterm lambs and was lower still in neonatal animals, whereas no variation was observed in EP3 receptor gene expression. Expression of the EP4 receptor gene was also confirmed in fetal baboon ductus arteriosus, and maternal administration of corticosteroid did not reduce EP4 receptor gene expression in the baboon. We conclude that advancing gestational age and birth may inhibit prostaglandin E2-mediated relaxation of the ductus through a corticosteroid-independent reduction in EP4 receptor gene expression.

Adrenal Cortex Hormones↗

PubMed2001

Influence of the natural microbial flora on the acid tolerance response of Listeria monocytogenes in a model system of fresh meat decontamination fluids.

Depending on its composition and metabolic activity, the natural flora that may be established in a meat plant environment can affect the survival, growth, and acid tolerance response (ATR) of bacterial pathogens present in the same niche. To investigate this hypothesis, changes in populations and ATR of inoculated (10(5) CFU/ml) Listeria monocytogenes were evaluated at 35 degrees C in water (10 or 85 degrees C) or acidic (2% lactic or acetic acid) washings of beef with or without prior filter sterilization. The model experiments were performed at 35 degrees C rather than lower (</=15 degrees C) temperatures to maximize the response of inoculated L. monocytogenes in the washings with or without competitive flora. Acid solution washings were free (<1.0 log CFU/ml) of natural flora before inoculation (day 0), and no microbial growth occurred during storage (35 degrees C, 8 days). Inoculated L. monocytogenes died off (negative enrichment) in acid washings within 24 h. In nonacid (water) washings, the pathogen increased (approximately 1.0 to 2.0 log CFU/ml), irrespective of natural flora, which, when present, predominated (>8.0 log CFU/ml) by day 1. The pH of inoculated water washings decreased or increased depending on absence or presence of natural flora, respectively. These microbial and pH changes modulated the ATR of L. monocytogenes at 35 degrees C. In filter-sterilized water washings, inoculated L. monocytogenes increased its ATR by at least 1.0 log CFU/ml from days 1 to 8, while in unfiltered water washings the pathogen was acid tolerant at day 1 (0.3 to 1.4 log CFU/ml reduction) and became acid sensitive (3.0 to >5.0 log CFU/ml reduction) at day 8. These results suggest that the predominant gram-negative flora of an aerobic fresh meat plant environment may sensitize bacterial pathogens to acid.

Acetic Acid↗

PubMed2001

Expression of prostanoid receptor genes in baboon chorion and decidua during pregnancy and parturition.

The aim of this study was to determine whether expression of prostanoid receptor genes varied with gestational age or labour in the decidua and chorion of baboons. Tissues were obtained at the time of Caesarean hysterectomy in 15 baboons, 10 prior to the onset of labour in the last third of pregnancy and 5 in spontaneous labour at term. Expression of prostanoid receptor genes was determined using Northern blot analysis and the level of expression was related to each of three housekeeping genes. Expression of the genes encoding the EP(1) and FP receptor in decidua and the EP(4) receptor in chorion was lower with advancing gestational age. Expression of the EP(2) receptor gene was lower in labour in decidua, whereas expression of the IP receptor gene was higher in labour in both decidua (twofold) and chorion (fourfold). It is concluded that there is a complex pattern of change in expression of prostanoid receptor genes in chorion and decidua with advancing gestational age and in association with labour. It seems likely that direct effects of prostaglandins on the choriodecidua may have an important role in parturition in the primate.

Animals↗

PubMed2001

Incidence of injection-site lesions in beef top sirloin butts.

Damaged beef muscle tissue resulting from intramuscular injections of animal-health products represents a "quality control" problem and an economic loss to the beef industry. Fifteen individual and sequential national audits of injection-site lesions in beef top sirloin butts have been conducted at the steak provisioner/cutting level between November 1995 and July 2000. The national incidence of injection-site lesions in top sirloin butts (n = 240,080) decreased (P < 0.05) between November 1995 (11.4%) and July 2000 (2.1%). From November 1995 to July 1997, mean weight per injection-site lesion, across all lesion classes, increased (P < 0.05) from 192.5 g to 435.8 g, respectively; mean weight per lesion subsequently decreased (P < 0.05) to 249.8 g in July 2000 but was still heavier (P < 0.05) than in November 1995. Results of these audits suggest that producers have changed injection practices. These changes have likely been in response to educational efforts, such as those made by National Cattlemen's Beef Association and through state beef quality assurance programs. Analyses of results for lesion classes, partitioning lesions according to chronological stages of the healing process, suggested that the majority of lesions were induced at times that coincide with cow-calf, stocker, or early finishing-period stages of cattle production.

Animals↗

PubMed2001

National market cow and bull beef quality audit-1999: a survey of producer-related defects in market cows and bulls.

The 1999 National Market Cow and Bull Beef Quality Audit comprised face-to-face interviews with industry representatives (n = 49); in-plant evaluations of cattle in holding pens (n = 3,969), carcasses on harvest floors (n = 5,679), and in carcass coolers (n = 4,378); and a strategy workshop. Face-to-face interviews suggested that the beef industry was most frequently concerned about the presence of antibiotic residues in carcasses, presence of lead shot in carcasses, and price discovery for carcasses following excessive trimming of bruises and testing due to arthritic joints, pathogens, or antibiotic residues. Although live animal evaluations determined that 73.4% of beef cows, 60.8% of dairy cows, 63.7% of beef bulls, and 70.9% of dairy bulls did not exhibit evidence of lameness, losses due to lameness were greater (P < 0.05) than in the 1994 National Non-Fed Beef Quality Audit. In-plant audits revealed that 88.9, 10.3, and 88.2% of cow carcasses and 18.9, 21.2, and 52.9% of bull carcasses had inadequate muscling, arthritic joints, and at least 1 bruise, respectively, all of which resulted in greater (P < 0.05) losses than the same defects in 1994. Audits revealed that 88.9% of cow carcasses and 18.9% of bull carcasses were lightly muscled, resulting in greater (P < 0.05) losses for cow carcasses, and similar (P > 0.05) losses for bull carcasses, than the same defect in the 1994 audit. Also, 14.5 and 30.8% of cow carcasses and 6.9 and 5.9% of bull carcasses had excess external fat and yellow-colored external fat, respectively, which was an improvement (P < 0.05) over 1994 results. In aggregate, 24.1, 19.2, 7.2, 6.7, 9.5, and 1.1% of livers, tripe, hearts, heads, tongues, and whole cattle or carcasses, respectively, were condemned and 60.6, 2.4, and 46.5% of cattle had hide damage from latent defects, insect damage, and brands, respectively. Condemnation rates were generally lower (P < 0.05), but tongue condemnations and frequency of branded hides were higher (P < 0.05) than in 1994. Producers should promote value in cows and bulls by managing to minimize quality defects, monitoring health and condition, and marketing in a timely manner. Using these techniques, producers might have recaptured $13.82, $27.50, and $27.50, respectively, for each cow or bull harvested in 1999.

Animal Husbandry↗

PubMed2001

Evaluation of the Tendertec beef grading instrument to predict the tenderness of steaks from beef carcasses.

Four experiments were conducted, using carcasses from cattle identified for anticipated variability in tenderness (Exp. 1, 2, and 3) and carcasses selected for variability in physiological maturity and marbling score (Exp. 4), to evaluate the ability of the Tendertec Mark III Beef Grading Probe (Tendertec) to predict tenderness of steaks from beef carcasses. In Exp. 1, 2, and 3, longissimus steaks were aged for different periods of time, cooked to a medium degree of doneness (70 degrees C), and evaluated for Warner-Bratzler shear force (WBS) and trained sensory panel ratings. In Exp. 4, longissimus steaks were aged 14 d and cooked to 60, 65, 70, 75, or 80 degrees C for WBS tests and to 65 or 75 degrees C for sensory panel evaluations. Tendertec output variables were not correlated with 1) 24-h calpastatin activity, steak WBS (following 1, 4, 7, 14, 21, or 35 d of aging), or d-14 sensory panel tenderness ratings in Exp. 1 (n = 467 carcasses) or 2) 14-d WBS in Exp. 2 (n = 202 carcasses). However, in Exp. 3 (n = 29 carcasses), Tendertec output variables were correlated (P < 0.05) with tenderness of steaks aged 1, 21, 28, or 35 d, and we were able to separate carcasses into groups yielding tough, acceptable, and tender steaks. In Exp. 4 (n = 70), Tendertec output variables were correlated (P < 0.05) with steak WBS at 60 degrees C and with steak ratings for muscle fiber tenderness, connective tissue amount, and overall tenderness at 65 degrees C, but these relationships weakened (P > 0.05) as degree of doneness increased. Consequently, Tendertec output variables only were effective for stratifying carcasses according to tenderness when steaks from those carcasses in Exp. 4 were cooked to a rare or medium-rare degree of doneness. Although Tendertec was able to sort carcasses of older, mature cattle based on tenderness of steaks at some cooked end points, it failed to detect tenderness differences in steaks derived from youthful carcasses consistently, and was thus of limited value as an instrument for use in improving the quality, consistency, and uniformity of the U.S. fed-beef supply.

Animals↗

PubMed2001

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.

Animals↗

PubMed2001

Supranutritional oral supplementation with vitamin D3 and calcium and the effects on beef tenderness.

Ultimate meat tenderness can be influenced by numerous preslaughter and postmortem management techniques. Increased levels of intracellular Ca2+, through postmortem injection, infusion, or marination, have been shown to improve the tenderness of cooked meat products. Oral supplementation with vitamin D3 effectively increases serum Ca2+ and has been hypothesized to increase muscle Ca2+ content, the activity of muscle proteases, and thus the tenderness of cooked beef. Individual Charolais x Hereford heifers (n = 191) were assigned to an unsupplemented control group or groups that were supplemented via oral bolus (for dose regulation purposes) with one of seven levels of vitamin D3 (1, 2, 3, 4, or 5 x 10(6) IU D3/d, 2 x 10(6) IU DS/d plus 75 g CaCO3 or 4 x 106 IU D3/d plus 75 g CaCO3) for 2, 4, 6, or 8 d antemortem. Individual feedlot performance, serum Ca2+ levels, and carcass data were collected, and eight longissimus steaks/carcass were used to obtain Warner-Bratzler shear force values measured at 2, 7, 14, and 21 d postmortem for longissimus steaks cooked to 70 degrees or 85 degrees C. Cattle supplemented with 4 x 10(6) IU D3/d plus 75 g of CaCO3 had lower daily feed intake (as-fed) and reduced (P < 0.05) average daily gains compared with controls during the 8-d supplementation period. Additionally, supplemented cattle had numerically higher dressing percentages, possibly due to less fill at the time of slaughter, because carcass weights and USDA yield grades did not differ (P > 0.05) across treatment groups. Supplementation with 1, 2, 3, 4, or 5 x 10(6) IU D3/d, for 2 or more days, increased (P < 0.05) serum Ca2+ concentrations compared with controls. Whereas cattle that received additional dietary Ca2+ in the form of CaCO3 had the lowest blood serum Ca2+ concentration. Although blood serum Ca2+ was increased, supplementation with any level of vitamin D3 for any length of time up to 8 d did not improve (P > 0.05) Warner-Bratzler shear force at 2, 7, 14, or 21 d of postmortem aging compared with controls when steaks were cooked to final internal temperatures of either 70 (control means 6.27, 4.91, 4.64, and 3.80 kg, respectively) or 85 degrees C (control means 7.31, 5.32, 4.69, and 4.46 kg, respectively). Results indicated that oral supplementation with vitamin D3 (at high or low doses) for 2 to 8 d before slaughter increased serum Ca2+ concentration but does not improve cooked longissimus tenderness.

Administration, Oral↗

PubMed2001

Effects of three levels of alpha-tocopheryl acetate supplementation to feedlot cattle on performance of beef cuts during retail display.

Retail packages (n = 288; 24 of each product in each treatment group) of inside round steaks, T-bone steaks (strip loin and tenderloin), top sirloin steaks, and ground beef were used to evaluate effects of dietary supplementation of vitamin E to cattle on product performance during retail display. Products from control animals and cattle fed 500 IU x animal(-1) x d(-1) or 1,000 IU x animal(-1) x d(-1) were evaluated. Except for ground beef, dietary supplementation of vitamin E increased (P < 0.05) alpha-tocopherol concentrations in beef muscle from cattle fed 1,000 IU x animal(-1) x d(-1). Although not all differences were statistically significant, retail display-life was greater for all steaks from cattle fed 1,000 IU x animal(-1) x d(-1) than for those from control cattle. Ten percent of the inside round and tenderloin steaks from cattle fed 1,000 IU x animal(-1) x d(-1) had mean overall appearance scores of 3 ("moderately undesirable") at 72 to 78 h and 54 to 60 h, respectively, whereas 10% of the inside round and tenderloin steaks from control cattle had mean overall appearance scores of 3 at 54 to 60 h and 42 to 48 h, respectively. Each of the retail cuts in this study (irrespective of the amount of alpha-tocopheryl acetate that was fed to the animal that generated it) was categorized as "high," "medium," or "low," based on the alpha-tocopherol concentration in the primal cut or ground beef batch from which it originated. Retail cuts in the medium a-tocopherol concentration category had increased retail display life of 4.0 h for ground beef (P < 0.05) over those in the low alpha-tocopherol category. Retail cuts in the high alpha-tocopherol concentration category had increased retail display life of 10.7 h for inside round steaks and 4.0 h for ground beef (P < 0.05) over those in the medium concentration category. Vitamin E supplementation of cattle at 1,000 IU x animal(-1) x d(-1) for at least 100 d can be used to increase retail caselife and to improve the overall color acceptability of steaks and ground beef products. Although far from a perfect relationship, these data strongly suggest that increasing the alpha-tocopherol concentration in a beef cut will increase its retail case life.

Animal Feed↗

PubMed2001

Detection of eastern equine encephalitis virus in infected mosquitoes using a monoclonal antibody-based antigen-capture enzyme-linked immunosorbent assay.

Surveillance of mosquito populations for virus activity is not often performed by small, vector-control districts because they do not have the financial resources to use virus isolation, or newer methods such as the polymerase chain reaction. Consequently, development and refinements of rapid, sensitive, and simple enzyme-linked immunosorbent assays (ELISAs) applicable to a wide variety of public health settings are justified. We have developed an antigen-capture ELISA for the detection of eastern equine encephalitis (EEE) virus in mosquitoes that uses both monoclonal capture and detector antibodies. The sensitivity of this assay is 4.0-5.0 log10 plaque-forming units/ml, which is comparable to previously published EEE antigen-capture assays developed with polyclonal antibody reagents. This test identifies only North American strains of EEE virus and does not react with either western equine encephalitis or Highlands J viruses. Test sensitivity was enhanced by sonicating mosquito pools, treating them with Triton X-100, and increasing the time and temperature of antigen incubation. The conversion of this ELISA to a monoclonal antibody-based format should result in a readily standardizable and transferable assay that will permit laboratories lacking virus isolation facilities to conduct EEE virus surveillance.

Aedes↗

PubMed2001

Organic acids and their salts as dipping solutions to control listeria monocytogenes inoculated following processing of sliced pork bologna stored at 4 degrees C in vacuum packages.

Postprocessing contamination of cured meats with Listeria monocytogenes has become a major concern for the meat processing industry and an important food safety issue. This study evaluated aqueous dipping solutions of organic acids (2.5 or 5% lactic or acetic acid) or salts (2.5 or 5% sodium acetate or sodium diacetate, 5 or 10% sodium lactate, 5% potassium sorbate or potassium benzoate) to control L. monocytogenes on sliced, vacuum-packaged bologna stored at 4 degrees C for up to 120 days. Organic acids and salts were applied by immersing (1 min) in each solution inoculated (10(2) to 10(3) CFU/cm2) slices of bologna before vacuum packaging. Growth of L. monocytogenes (PALCAM agar) on inoculated bologna slices without treatment exceeded 7 log CFU/cm2 (P < 0.05) at 20 days of storage. No significant (P > 0.05) increase in L. monocytogenes populations occurred on bologna slices treated with 2.5 or 5% acetic acid, 5% sodium diacetate, or 5% potassium benzoate from day 0 to 120. Products treated with 5% potassium sorbate and 5% lactic acid were stored for 50 and 90 days, respectively, before a significant (P < 0.05) increase in L. monocytogenes occurred. All other treatments permitted growth of the pathogen at earlier days of storage, with sodium lactate (5 or 10%) permitting growth within 20 to 35 days. Extent of bacterial growth on trypticase soy agar plus 0.6% yeast extract (TSAYE) was similar to that on PALCAM, indicating that the major part of total bacteria grown on TSAYE agar plates incubated at 30 degrees C was L. monocytogenes. Further studies are needed to evaluate organic acids and salts as dipping solutions at abusive temperatures of retail storage, to optimize their concentrations in terms of product sensory quality, and to evaluate their effects against various other types of microorganisms and on product shelf life. In addition, technologies for the commercial application of postprocessing antimicrobial solutions in meat plants need to be developed.

Acetates↗

PubMed2001

Antimicrobials in the formulation to control Listeria monocytogenes postprocessing contamination on frankfurters stored at 4 degrees C in vacuum packages.

Postprocessing contamination of cured meat products with Listeria monocytogenes during slicing and packaging is difficult to avoid, and thus, hurdles are needed to control growth of the pathogen during product storage. This study evaluated the influence of antimicrobials, included in frankfurter formulations, on L. monocytogenes populations during refrigerated (4 degrees C) storage of product inoculated (10(3) to 10(4) CFU/cm2) after peeling of casings and before vacuum packaging. Frankfurters were prepared to contain (wt/wt) sodium lactate (3 or 6%, as pure substance of a liquid, 60% wt/wt, commercial product), sodium acetate (0.25 or 0.5%), or sodium diacetate (0.25 or 0.5%). L. monocytogenes populations (PALCAM agar and Trypticase soy agar plus 0.6% yeast extract [TSAYE]) exceeded 10(6) CFU/cm2 in inoculated controls at 20 days of storage. Sodium lactate at 6% and sodium diacetate at 0.5% were bacteriostatic, or even bactericidal, throughout storage (120 days). At 3%, sodium lactate prevented pathogen growth for at least 70 days, while, in decreasing order of effectiveness, sodium diacetate at 0.25% and sodium acetate at 0.5 and 0.25% inhibited growth for 20 to 50 days. Antimicrobials had no effect on product pH, except for sodium diacetate at 0.5%, which reduced the initial pH by approximately 0.4 U. These results indicate that concentrations of sodium acetate currently permitted by the U.S. Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS) (0.25%) or higher (0.5%) may control growth of L. monocytogenes for approximately 30 days, while currently permitted levels of sodium lactate (3%) and sodium diacetate (0.25%) may be inhibitory for 70 and 35 to 50 days, respectively. Moreover, levels of sodium lactate (6%) or sodium diacetate (0.5%) higher than those presently permitted by the USDA-FSIS may provide complete control at 4 degrees C of growth (120 days) of L. monocytogenes introduced on the surface of frankfurters during product packaging.

Animals↗

PubMed2001

Extent of microbial contamination in United States pork retail products.

To determine the extent of microbiological contamination of U.S. pork, 384 samples of retail pork were collected from 24 stores in six cities, including (i) whole-muscle, store-packaged pork; (ii) fresh, store-packaged ground pork and/or pork sausage; (iii) prepackaged ground pork and/or pork sausage; and (iv) whole-muscle, enhanced (injected or marinated; 60% store-packaged, 40% prepackaged) pork. Additional samples (n = 120) of freshly ground pork and/or pork sausage were collected from two hot-boning sow/boar sausage plants, two slaughter and fabrication plants, and two further-processing plants. Samples were analyzed for aerobic plate counts (APC), total coliform counts (TCC), Escherichia coli counts (ECC), and incidences of Salmonella spp., Listeria monocytogenes, Campylobacter jejuni, Campylobacter coli, and Yersinia enterocolitica. Mean log APC and TCC were highest (P < 0.05) for store-ground pork, while whole-muscle, enhanced products and prepackaged ground products had the lowest (P < 0.05) APC. Mean log APC and TCC were higher (P < 0.05) in samples from the slaughter and fabrication plants than in samples from hot-boning and further processing plants. Mean log ECC were lower (P < 0.05) in samples from further-processing plants compared to slaughter and fabrication plants and hot-boning, sow and boar sausage plants. L. monocytogenes was detected in 26.7% of plant samples and 19.8% of retail samples and was present more frequently in ground products. Y. enterocolitica was detected most often in whole-muscle, store-packaged cuts (19.8%) and in store-ground product (11.5%). Salmonella spp. were found in 9.6% of retail samples and 5.8% of plant samples, while C. jejuni and C. coli were found in 1.3% of retail samples and 6.7% of plant samples. Pork products exposed to the most handling and processing appeared to be of the poorest microbiological quality. These results should be useful in risk assessments that are directed at the identification of actions that could enhance food safety.

Animals↗

PubMed2001

Microbial contamination occurring on lamb carcasses processed in the United States.

Lamb carcasses (n = 5,042) were sampled from six major lamb packing facilities in the United States over 3 days during each of two visits (fall or winter, October through February; spring, March through June) in order to develop a microbiological baseline for the incidence (presence or absence) of Salmonella spp. and for populations of Escherichia coli after 24 h of chilling following slaughter. Samples also were analyzed for aerobic plate counts (APC) and total coliform counts (TCC). Additionally, incidence (presence or absence) of Campylobacter jejuni/coli on lamb carcasses (n = 2,226) was, determined during the slaughtering process and in the cooler. All samples were obtained by sponge-sampling the muscle-adipose tissue surface of the flank, breast, and leg of lamb carcasses (100 cm2 per site; 300 cm2 total). Incidence of Salmonella spp. in samples collected from chilled carcasses was 1.5% for both seasons combined, with 1.9% and 1.2% of fall or winter and spring samples being positive, respectively. Mean (log CFU/cm2) APC, TCC, and E. coli counts (ECC) on chilled lamb carcasses across both seasons were 4.42, 1.18, and 0.70, respectively. APC were lower (P < 0.05) in samples collected in the spring versus fall or winter, while TCC were higher in samples collected in the spring. There was no difference (P > 0.05) between ECC from samples collected in the spring versus winter. Only 7 out of 2,226 total samples (0.3%) tested positive for C. jejuni/coli, across all sampling sites. These results should be useful to the lamb industry and regulatory authorities as new regulatory requirements for meat inspection become effective.

Abattoirs↗

PubMed2001

Fate of Escherichia coli O157:H7, Salmonella typhimurium DT 104, and Listeria monocytogenes in fresh meat decontamination fluids at 4 and 10 degrees C.

Bacterial pathogens may colonize meat plants and increase food safety risks following survival, stress hardening, or proliferation in meat decontamination fluids (washings). The objective of this study was to evaluate the ability of Escherichia coli O157:H7, Salmonella Typhimurium DT 104, and Listeria monocytogenes to survive or grow in spray-washing fluids from fresh beef top rounds sprayed with water (10 or 85 degrees C) or acid solutions (2% lactic or acetic acid, 55 degrees C) during storage of the washings at 4 or 10 degrees C in air to simulate plant conditions. Inoculated Salmonella Typhimurium DT 104 (5.4 +/- 0.1 log CFU/ml) died off in lactate (pH 2.4 +/- 0.1) and acetate (pH 3.1 +/- 0.2) washings by 2 days at either storage temperature. In contrast, inoculated E. coli O157:H7 (5.2 +/- 0.1 log CFU/ml) and L. monocytogenes (5.4 +/- 0.1 log CFU/ml) survived in lactate washings for at least 2 days and in acetate washings for at least 7 and 4 days, respectively; their survival was better in acidic washings stored at 4 degrees C than at 10 degrees C. All inoculated pathogens survived in nonacid (pH > 6.0) washings, but their fate was different. E. coli O157:H7 did not grow at either temperature in water washings, whereas Salmonella Typhimurium DT 104 failed to multiply at 4 degrees C but increased by approximately 2 logs at 10 degrees C. L. monocytogenes multiplied (0.6 to 1.3 logs) at both temperatures in water washings. These results indicated that bacterial pathogens may survive for several days in acidic, and proliferate in water, washings of meat, serving as potential cross-contamination sources, if pathogen niches are established in the plant. The responses of surviving pathogens in meat decontamination waste fluids to acid or other stresses need to be addressed to better evaluate potential food safety risks.

Air↗

PubMed2001

Ethics.

Explore the source record for details and available documents.

Dentistry, Operative↗

PubMed2000

Sex, birth weight, and the risk of stillbirth in Scotland, 1980-1996.

The aim of this study was to determine whether the risk of stillbirth associated with male fetal sex was modified by fetal growth. The study group consisted of all singleton first births weighing greater than 500 g delivered between 28 and 43 weeks gestation in Scotland in 1980-1996 (n = 469,152). Overall, male fetuses were at an increased risk of stillbirth (relative risk = 1.19, 95 percent confidence interval: 1.10, 1.29). There was a significant negative interaction between male sex and increasing birth weight quintile in term, but not preterm, births. The interaction was virtually identical when calculated independently for births in the periods 1980-1987 and 1988-1996. There were linear decreases in the proportion of stillbirths and the proportion of birth weights in the lowest quintile over the period 1980-1996. Adjustment for year of birth did not affect the relation between male sex and stillbirth. However, adjustment for birth weight resulted in a loss of the association between year of birth and risk of stillbirth. The authors concluded that 1) the association between male sex and stillbirth diminishes with increasing birth weight quintile, and 2) there was a fall in the proportion of stillbirths in Scotland between 1980 and 1996, which may have been due to a fall in the proportion of small babies over the same period.

Birth Weight↗