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Survival Of Microorganisms On Meat Surfaces Treated With Ultra-High Temperatures, Bret Max Mattinson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sterile ceramic plates and the surface of beef steaks were inoculated with the pathogenic microorganisms Listeria monocytogenes, Campylobacter jejuni, Escherichia coli and Salmonella typhimurium. Samples were also inoculated with nonpathogenic microorganisms Clostridium sporogenes ATCC 7955, Pseudomonas aeruginosa, and Bacillus stearothermophilus. Concentrations of organisms in the pure culture used to inoculate the samples were selected within the range of 10⁶ to 10⁸ colony forming units/ml (CFU/ml). Samples were treated with ultra-high temperature (UHT), and· the surviving organisms were recovered and counted. Meat samples were exposed to 1100°C for 22 seconds.

Beef steaks inoculated with pathogenic microorganisms had …