No description available.

Master of Science / Food Science Institute / Randall Phebus / Shiga toxin-producing E. coli (STEC) are frequently associated with foodborne illness outbreaks, especially attributable to beef. Intervention methods, such as water washes and organic acid application, are widely implemented across the beef industry to combat this risk. This research evaluates the efficacy of intervention methods applied to chilled beef subprimal pieces and pre-rigor beef carcasses to reduce STEC contamination. Beef strip loins were inoculated (ca. 5 log CFU/cm²) with a 7-serotype STEC cocktail and sprayed with increasing concentrations of peracetic acid (200-1800 ppm; ambient temperature), lactic acid (3-10%; 55°C), or a water control before being vacuum-packaged and stored for 24 h at 4°C. Meat surface excision samples and color readings (L*, a*, and b*) were obtained from each subprimal at three sampling points: post-inoculation, 5 min post chemical spray, and post-24 h vacuum packaged chilling. Peracetic acid spray and lactic acid spray reduced STEC populations by 0.5 -1.3 log CFU/cm² and 0.2 – 0.7 log CFU/cm², respectively, across the incremental concentration increases. All concentrations of peracetic acid and lactic acid concentrations ≥3.5% reduced (P ≤ 0.05) STEC populations compared to their respective control. Application of higher concentrations of lactic acid (7-10%) decreased (P ≤ 0.05) L* and b* values compared to the control, indicating that quality attributes of the subprimals were negatively effected. Carcass intervention methods were evaluated using a three-stage commercial carcass washing cabinet (Chad Equipment). Four pre-rigor carcass sides were inoculated by electrostatically spraying with a 7-serogroup STEC cocktail (ca. 6.5 log CFU/100 cm²). Three treatments were applied, in order, to each side: ambient water wash, hot water wash (82-92°C at the nozzle head), and antimicrobial mist. Meat surface excision samples were taken from the bottom, middle, and top section of each carcass side at five sampling points: 30 min post-inoculation, post-ambient water wash, post-hot water wash, post-antimicrobial spray, and after 18 h spray chilling. The combination of the high-volume ambient water wash stage and subsequent hot water wash stage reduced STEC populations on sides by 3.5, 4.7, and 4.8 log CFU/100 cm² at the bottom, middle, and top of the carcass, respectively. Due to STEC populations declining to very low or undetectable levels after the hot water stage, minimal additional STEC reductions were observed after chemical spray application and chilling. Sequential antimicrobial treatments applied using a three-stage Chad carcass wash cabinet and a subsequent chill step reduced STEC populations on pre-rigor beef carcasses by 4.5 – 5.3 log CFU/100 cm².

Callipyge (CLPG, n=16) and normal (N, n=11) lambs were produced from Polypay dams and Dorset sires heterozygous for the CLPG gene to study the effects of the gene on growth and carcass and meat quality parameters. CLPG lambs had higher average daily gain than N lambs (0.26 vs 0.23 kg/day, p<.05); however, the CLPG gene did not affect feed efficiency. Lambs were slaughtered in three groups to achieve moderate uniformity in slaughter weight. At the time of slaughter, weights of head, pelt, and internal organs were recorded. Two leg muscles, two shoulder muscles, the longissimus dorsi muscle, and two loin chops cut 2.5 cm thick, were dissected from each carcass. CLPG lambs had a higher dressing percent (p<.01) and lighter head, pelt, liver (all p<.01), and kidney/pelvic fat (p<.05). CLPG lambs had less fat over 12th rib (p<.05) and larger ribeye area (p<.01). CLPG lambs had greater weights of Biceps femoris (42%, p<.05), Semimembranosus (34%, p<.01), Triceps brachii (20%, p<.05), longissimus dorsi muscle (29%, p<.01) and whole leg (6%, p<.05) than N lambs. All the dissected muscles from all carcasses and one whole leg from each ewe lamb carcasses (n=11) were cooked to an internal temperature of 70��C. CLPG carcasses produced higher Warner-Bratzler shear values for loin chops (4.79 vs 2.93 kg, p<.01), Biceps femoris (3.94 vs 2.92 kg, p<.05), Semimembranosus (4.75 vs 3.46 kg, p<.05) and Longissimus dorsi muscle (5.29 vs 3.4 kg, p<.01) than N lambs. However, no significant differences were detected in shear values for Biceps femoris (3.10 vs 3.04 kg) or Semimembranosus (3.77 vs 3.29 kg) when the muscles were dissected after roasting the whole leg. The CLPG gene also had no effect on the shear values for two dissected shoulder muscles (Deltoid and Triceps brachii). The two genotypes did not differ in either cooking loss or percent moisture in any of the muscles compared. / Graduation date: 1998

Antimicrobial interventions implemented in slaughter establishments for the reduction of enteric pathogens on beef carcasses must be validated to demonstrate efficacy under commercial operation conditions. Validation studies can be conducted using surrogates which are nonpathogenic organisms that respond to a particular treatment in a manner equivalent to a target pathogen. The purpose of this study was to identify surrogates for enteric pathogens to validate antimicrobial interventions on beef carcasses. The growth, attachment, resistance properties as well as the response to interventions on beef carcasses of nonpathogenic fluorescent protein-marked E. coli strains were evaluated and compared to E. coli O157:H7 and Salmonella strains. Growth curves were performed in tryptic soy broth at 37°C and it was demonstrated that in general, growth parameters were not different among surrogates and target pathogens. Thermal resistance was compared in phosphate buffered saline (PBS) at 55, 60 and 65°C; D-values of surrogates were not different or were higher than those of target pathogens. The acid resistance of surrogates was not different to that of E. coli O157:H7 in PBS acidified with lactic acid at pH 2.5, 3.0 and 3.5. Some Salmonella serotypes were found to be less acid resistant than the surrogates. Survival of surrogates after storage at low temperatures (4°C and -18°C) was not different or was longer than survival of E. coli O157:H7 and Salmonella. Additionally, the cell surface hydrophobicity and attachment to beef carcasses surfaces was not different among surrogates and pathogens. Antimicrobial interventions were applied on carcass surfaces under laboratory controlled conditions. After application of hot water washes, D-values were not different among surrogates and pathogens, while no differences were observed in log reductions (CFU/cm2) among surrogates and pathogens when 2% L-lactic acid sprays at 25 and 55°C were applied, regardless of the temperature and volume of the acid solution. The response of surrogates to water washes and lactic acid sprays on beef carcasses was also evaluated in commercial slaughter facilities. Reductions of surrogates were not different to those of aerobic plate count, coliforms and E. coli. However, the surrogates showed less variation and provided more consistent results than traditional indicators.

No description available.

Data from the 2001-2002 Texas A&M University Ranch to Rail Program-South were used to determine factors that influence cattle feedlot performance and profitability. Steers (n=860) were classified according to sire (SBIO) and dam (DBIO) biological groups, kill groups (KILL), and entry month (ENTRYMON). Biological groups were determined by predominant genetic make up of the sire or dam. Traits evaluated included net income (NI), feedlot average daily gain (ADG), slaughter weight (OUTWT), carcass weight (CW), fat thickness (FT), longissimus muscle area (LMA), marbling score (MS), yield grade, (YG), medicine costs (TOTMED), and carcass value (CVL). Analyses of covariance were performed to determine differences between SBIO and DBIO, KILL, and ENTRYMON, and the influence of initial feedlot weight (INWT). Sire biological type had a significant effect on NI, ADG, FT, LMA, MS, YG, and CVL. Dam biological type and KILL had significant effects on all traits excluding TOTMED. Entry month accounted for no differences. Among SBIO groups, British-sired steers exhibited greatest values for ADG (1.39 kg/d), MS (457), FT (1.45 cm), CVL ($891), and NI ($25.62). Continental-sired steers exhibited the largest LMA (97.65 cm) and lowest YG (2.51). Brahman-sired steers exhibited the lowest ADG (1.32kg/d), MS (405), CVL ($859), and NI ($-17.80). Multiple regression was performed to determine which traits had the greatest effect on CVL and NI. Independent categorical effects were SBIO, DBIO, KILL and ENTRYMON, while independent continuous effects were INWT, ADG, FT, LMA, MS and TOTMED. Both CVL and NI were influenced by CW, FT, LMA, and MS, but not by ADG, INWT, or TOTMED. Phenotypic correlation coefficients were determined among all traits. Highest correlations were present between CVL: and NI, CW, ADG, and LMA (0.80, 0.81, 0.54, and 0.49, respectively). Strong correlations were seen between ADG and CW (0.63), FT and YG (0.87) and YG and LMA (-0.51). Marbling score was moderately correlated to CVL (0.30) and NI (0.30). This study indicates that a wide variety of traits interact to determine CVL and NI in retained ownership programs, and that maximizing carcass value does not ensure increased profitability.

Thesis (M.I.S.)--University of Montana, 2008. / Title from title screen. Description based on contents viewed Nov. 18, 2008. Includes bibliographical references (p. 39-41).

Thesis (M.A.)--University of Montana, 2007. / Title from title screen. Description based on contents viewed Oct. 7, 2008. Includes bibliographical references (p. 62-64).

Typescript (photocopy).

Orientador: Edir Nepomuceno da Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T01:40:24Z (GMT). No. of bitstreams: 1 Jardim_FernandaBarbosaBorges_M.pdf: 743715 bytes, checksum: 9101df2cb92df47ccea84a3e56d2f3de (MD5) Previous issue date: 2005 / Resumo: O objetivo deste trabalho foi avaliar a contaminação microbiana da pele e superfície de carcaças bovinas, provenientes de bovinos em dois diferentes sistemas de alimentação. Foram selecionados 40 bovinos sadios da raça Nelore, separados em dois lotes de 20, que foram submetidos a dois sistemas de alimentação: extensiva em pastagem e intensiva em confinamento. Os animais foram abatidos no matadouro-frigorífico Boi Bravo sob SIF (Serviço de Inspeção Federal), localizado em Uberaba-MG, no período de Março a Dezembro de 2003. As amostras foram obtidas, conforme ABNT (Associação Brasileira de Normas Técnicas), pela técnica de esfregaço de superfície nas carcaças utilizando-se suabe. As contagens médias (log10 UFC/cm2) de aeróbios totais viáveis, coliformes totais e E. coli foram, respectivamente, 3,72, 1,27 e 0,86 (antes da esfola-na pele); 1,89, 0,40 e 0,40 (após a esfola-na carcaça); 2,19, 0,55 e 0,42 (após a lavagemna carcaça) para os bovinos de pastagem e 3,31, 0,65 e 0,64 (antes da esfola-na pele); 1,78, 0,40 e 0,40 (após a esfola-na carcaça); 1,82, 0,41 e 0,40 (após a lavagem-na carcaça) para os bovinos de confinamento. Os resultados na etapa antes da esfola apresentaram contagens médias mais elevadas, pois a pele pode apresentar acúmulos de fezes, microrganismos e sujeira sobre o pelame. A etapa após a lavagem apresentou contagem intermediária, sendo as etapas subseqüentes à esfola prováveis fontes de contaminação e a etapa após a esfola apresentou o menor nível de contaminação, indicando pequeno contato entre pele e carcaça. Os bovinos em pastagem apresentaram contagens médias superiores em relação aos bovinos em confinamento. Constatou-se que a pele dos animais em confinamento estavam em melhores condições gerais de higiene no momento do abate e, conseqüentemente, suas carcaças obtiveram menores contagens no abate. Sugere-se que as pastagens ofereceram um ambiente susceptível à contaminação dos bovinos, enquanto o ambiente restrito de confinamento ofereceu menores oportunidades de contaminação / Abstract: The objective of this research work was to evaluate the microbial contamination of the hide and surface from bovine carcasses, coming from cattle under two different feeding systems. Forty healthy bovine animals from Nelore breed were selected, being separated into two lots of 20 animals which were submitted to two feeding systems: extensive in pasture and intensive in feedlot. Animals were slaughtered under SIF (Federal Inspection Service) in the Boi Bravo slaughterhouse located in the region of the Uberaba-MG from March to December, 2003. The samples were obtained through the surface smear technique using swab on the bovine carcass, according to the ABNT (Brazilian Association of Technical Rules). The average counting (log10 CFU/cm2) for total viable aerobes, total coliforms and E. coli were respectively 3.72, 1.27 and 0.86 (before skinningon the hide); 1.89, 0.40 and 0.40 (after skinning-on the carcass); 2.19, 0.55 and 0.42 (before washing-on the carcass) for the pasture cattle and 3.31, 0.65 and 0.64 respectively (before skinning-on the hide); 1.78, 0.40 and 0.40 (after skinning-on the carcass); 1.82, 0.41 and 0.40 (before washing-on the carcass) for the feedlot cattle. The results in the stage before skinning presented higher average counting because the hide may present manure accumulation, microorganisms and dirt on the hair. The stage after washing presented an intermediate counting, the stages subsequent to skinning being probable sources of contamination and the stage after skinning exhibited the lowest contamination level indicating a low contact between the hide and carcass. Cattle in pasture presented higher average counting in relation to the cattle in feedlot. It was found that the hide from animals in feedlot was in better general conditions of hygiene at the moment of the slaughter and, consequently, their carcasses achieved the lowest contamination level at the slaughter. It was suggested that the pastures offered a susceptible environment to the contamination of cattle, while the restricted environment of feedlot offered fewer chances of contamination / Mestrado / Tecnologia de Alimentos / Mestre em Tecnologia de Alimentos