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Ecological superiority and inhibition of growth of pathogens in ground beef chubs produced from decontaminated beef carcasses
Abstract
Numerous studies have addressed the effectiveness of interventions designed to reduce numbers of bacteria on beef carcass surfaces. These treatments have included hot water, organic acids, and other sanitizers, and have been highly effective in reducing pathogens and spoilage organisms. Although these treatments are beneficial, unusual spoilage patterns due to the treatments have been claimed by members of the beef industry, including suggestions that meat becomes too clean with these treatments, and that pathogens might be able to grow faster due to a lack of competition secondary to reductions in the numbers and types of microflora. This study focused on reproducing conditions in ground beef production that may lead to unusual spoilage patterns or pathogen growth. In order to detect potential differences in spoilage patterns due to carcass decontamination treatments, bacteria were isolated and identified from packages of ground beef that were obtained from the treated carcasses. Additional studies were performed using beef inoculated with pathogens which included E. coli O157:H7 and Salmonella serotype Typhimurium. The treatments consisted of the application of one of three sanitizers to the carcass surface: hot water, lactic acid, or acetic acid. Ground beef was obtained from the treated carcass, packaged under a vacuum in high oxygen barrier bags, and stored at 10°C and 4°C, and then sampled for numbers of bacteria every seven days for seven weeks. Results from the present study indicate that antimicrobial treatments applied to carcasses are not likely to affect spoilage patterns in ground beef. Unusual spoilage patterns resembling those in industrial settings were only observed when packages were stored at elevated refrigeration temperatures (10°C). In addition, no treatment caused an excessive outgrowth of pathogens. Bacterial type distributions were similar for all treatments, indicating no selection of bacteria due to particular treatments. Based upon the data collected in this study, it is most likely that the unusual spoilage patterns reported in the industry are caused by storage in upper ranges of refrigeration temperatures, and not by changes in the microflora of the meat.
Description
Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references (leaves 65-68).
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Citation
Shellenberger, Amy King (2000). Ecological superiority and inhibition of growth of pathogens in ground beef chubs produced from decontaminated beef carcasses. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /ETD -TAMU -2000 -THESIS -S5423.
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