This study was conducted to determine the effectiveness of trimming the original external carcass surfaces from subprimals during fabrication on the reduction of surrogates for Escherichia coli O157:H7. Carcass sides from five cattle (n = 10 sides) were inoculated along the pattern hide opening before entering the blast chill cooler with a gelatin slurry containing a bacterial cocktail of three rifampicin-resistant, nonpathogenic E. coli Biotype I strains. Following a 48 h chill, sides were fabricated to produce eight subprimals (brisket, chuck, clod, rib, bottom round, top sirloin, short loin, and inside round). Microbiological samples were taken from the original carcass fat surface area, initial lean surface area, trimmed fat surface area (where applicable), and trimmed lean surface area (where applicable). Trimming of the external fat surfaces reduced (P < 0.05) microbiological counts on the newly exposed lean surfaces of all eight subprimals during fabrication. However, these data also indicated that fat and lean surfaces that were not initially exposed to contamination became contaminated during the fabrication process. Trimming external surfaces reduces levels of pathogens, but under normal fabrication processes, pathogens may still be spread to the newly exposed surfaces.

Master of Science / Department of Animal Sciences and Industry / Terry A. Houser / Nursery age pigs (n=198) were used to evaluate the difference in the occurrence of injection site abscesses between needle-free jet injection and conventional needle-and-syringe injection systems. Pigs were fed for 21 d prior to treatment administration to acclimate the pigs to the environment of the Kansas State University Segregated Early Weaning (SEW) unit. On d 21 each pig was injected with aluminum hydroxide adjuvant in the neck and ham with needle-free jet injection (Pulse Needle-Free Systems, Lenexa, KS) and conventional needle-and-syringe injection. Needle-free and conventional needle-and-syringe injections were randomly assigned to pig side yielding a total of 396 injections per treatment with a total of 792 injections sites. Immediately prior to injection, the external surface of the injection sites were contaminated with an inoculum of Arcanobacterium pyogenes, a bacterium commonly associated with livestock abscesses. The pigs were then fed for a period of 27 or 28 d. On d 27 or d 28 the pigs were humanely euthanized and sent to the Kansas State Veterinary Diagnostics Laboratory where necropsies were performed and the injection sites harvested for histopathological evaluation. The needle-free jet injection system was associated with more injection site abscesses than the conventional needle-and-syringe injection method for both neck (P=0.0625) and ham (P=0.0313) injection sites. Twelve abscesses were found at injection sites administered via needle-free jet injection method while only 1 abscess was found with the conventional needle-and-syringe injection method. 5 abscesses were found at the neck injection sites and 8 abscesses were found at ham injection sites. There were no significant differences seen in tissue granulation resulting from reaction to the adjuvant. In summary, the implementation of needle-free jet injection systems in market hog production will be beneficial to eliminate needles and needle fragments in meat products but, when in the presence of Arcanobacterium pyogenes, it may increase the occurrence of injection site abscesses in pork carcasses that will need to be trimmed in pork processing plants. Although more abscesses were associated with needle-free jet injection, their occurrence was observed at a very low rate given that all injection sites were intentionally contaminated prior to injection.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Resolution n.4 authorizes the use of carcasses washing systems in poultry slaughtering processes to remove contamination from visible gastrointestinal content present in the internal and external surfaces of the carcasses, as an alternative to trimming. The publication of this resolution led to uncertainty as to possible damage to the safety of the product. Thus, the objective of this study was to evaluate the initial results of implementing carcass washing in poultry slaughterhouses of Rio Grande do Sul state and to compare these data with those obtained in the same companies before the change in system, determining if the new system is or not equivalent to the traditional method. Additionally, we sought to evaluate the influence of pressure and water flow from the hoses used in the decontamination of carcasses. The percentages of total and partial condemnation by SIFs, technical data from washers (pressure at the outlet of the water jet spray nozzles and volume water per carcass) and the results from microbiological tests carried out at five slaughterhouses in Rio Grande do Sul state which have already implemented the system were collected. Total and partial condemnation, as well as mesophilic and enterobacteria counts were compared within each slaughterhouse before and after the washing system had been implemented using the chi-square test. The response variables were correlated to each other and to the washing system by means of Spearman correlation analysis, at 5% probability. Also correlation tests were conducted to verify that the different pressures and water flows from washers exerted influence in the decontamination of carcasses. Total condemnation differed between treatments at the slaughterhouse 3 and partial condemnations in Slaughterhouses 2, 3, and 4. The water pressure at the outlet of the sprinkler varied from 3.1 kgf / cm² to 16.3 kgf / cm² and water flow from 0.4 to 1.5 liters per carcass. Visible carcass contamination levels were not different between removal systems, except for Enterobacteriaceae counts at Slaughterhouse 3, which were reduced. There was a positive correlation between the pressure and water flow and the percentage of reduction of mesophilic and enterobacteria. Based on the results obtained in this study, it is clear that both systems were equivalent in the microbiological standpoint, however, if all evaluated washing equipment would use the most efficient parameters, the results of washing system would probably be better than the trimming; the washing system is superior to the trimming from an operational point of view; the pressure has a greater influence on the decontamination of carcasses than the water flow; Additional studies are needed to establish minimum acceptable standards of volume and water pressure for internal and external washing of carcasses in order to improve the method; the feasibility of replacing the carcasses trimming system with the washing system should also be studied in the Department of Final Inspection. / A Resolução n.4 autorizou o emprego do sistema de lavagem de carcaças no processo de abate de aves para remover a contaminação por conteúdo gastrintestinal visível presente nas superfícies internas e externas das carcaças, como alternativa à prática do refile e sua publicação gerou insegurança quanto a possíveis prejuízos à inocuidade do produto. Sendo assim, o objetivo deste trabalho foi avaliar os primeiros resultados da implantação da lavagem de carcaças nas indústrias avícolas do estado do Rio Grande do Sul e comparar esses dados com os obtidos nas mesmas empresas previamente à mudança do sistema, determinando se o novo sistema é equivalente ou não ao método tradicional de refile. Adicionalmente, buscou-se avaliar a influência da pressão e da vazão de água dos lavadores na descontaminação das carcaças. Coletaram-se os percentuais de condenações total e parcial realizadas pelos SIFs, dados técnicos dos lavadores (pressão do jato de água na saída dos bicos aspersores e volume de água por carcaça) e os resultados de análises microbiológicas nos cinco abatedouros que já implantaram o sistema no estado. As condenações totais e parciais, assim como as contagens de mesófilos e enterobactérias, foram comparadas dentro de cada frigorífico antes e após a implantação do sistema de lavagem por meio do teste do qui-quadrado. As variáveis resposta foram correlacionadas entre si e em função do sistema de lavagem por meio da análise de correlação de Spearman, a 5% de probabilidade. Também foram realizados testes de correlação a fim de verificar se as diferentes pressões e vazões de água dos lavadores exerceram influência na descontaminação das carcaças. As condenações totais diferiram entre os sistemas no Abatedouro 3 e as condenações parciais nos Abatedouros 2, 3, e 4. A pressão de água na saída dos bicos aspersores variou de 3,1 kgf/cm² até 16,3 kgf/cm² e a vazão de água de 0,4 até 1,5L por carcaça. Os níveis de contaminação das carcaças não diferiram nos dois sistemas de remoção da contaminação visível, com exceção das contagens de enterobactérias do Abatedouro 3, que reduziram. Observou-se correlação positiva entre a pressão e a vazão da água e os percentuais de redução de mesófilos e de enterobactérias. Com base nos resultados obtidos neste estudo, é possível afirmar que os sistemas de refile e de lavagem de carcaças foram equivalentes no aspecto microbiológico, no entanto, se todos os lavadores avaliados utilizassem os parâmetros dos mais eficientes, o resultado do sistema de lavagem provavelmente seria superior ao do refile; o sistema de lavagem é superior ao de refile do ponto de vista operacional; a pressão tem maior influência na descontaminação das carcaças do que a vazão; estudos adicionais são necessários para estabelecer padrões mínimos aceitáveis de volume e pressão de água para a lavagem interna e externa das carcaças, a fim de aprimorar o método; deve-se estudar a viabilidade da substituição do refile pela lavagem de carcaças também no Departamento de Inspeção Final.