The Application of Biological, Chemical, and Physiological Food Interventions on Meat Trim to decrease Salmonella Population in final Ground Products
Advisorde Mello, Amilton S
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The work presented in Chapter 1 was conducted to study the effects of bacteriophage application during tumbling on Salmonella populations in ground meat and poultry. Four strains associated with previous Salmonella outbreaks were used in the study. Strains included S. enterica (ATCC 51741), S. Heidelberg (ATCC 8326), S. Newport (ATCC 27869), and S. Enteritidis (Se 13) whereas a cocktail comprising of two bacteriophages (S16 and FO1a) was applied as an antimicrobial intervention. Intact beef and pork trimmings and turkey and chicken thighs were inoculated with all four Salmonella strains to result in a contamination level of 7 log CFU/g. Bacteriophages were applied during tumbling, a common process used to treat meat parts with antimicrobials. Subsequently, samples were individually ground and Salmonella counts were enumerated. Results indicated that bacteriophage applications during tumbling of intact meat provided additional Salmonella control in ground products. The work presented in Chapter 2 evaluated the effects of organic acids (lactic and peroxyacetic), bacteriophages S16 and FO1a, and ultraviolet light (UV), as well as combinations of those interventions on Salmonella populations of ground beef. Beef trim samples (80% lean 20% fat) were inoculated with the same four Salmonella strains used in the first experiment, resulting in a contamination level of 3.5 log CFU/g. Organic acids and bacteriophage solutions were pipetted on the surface of inoculated samples, whereas UV was applied by tumbling (800 µW/cm2 for 30 seconds). Samples were ground and Salmonella counts were enumerated. Results indicated that organic acids commonly used as antimicrobials by the industry do not significantly reduce Salmonella in ground products. Applications combining bacteriophages and UV led to a 99% reduction (2 log cycles) of Salmonella in ground beef when applied on trim.