Date of Award:

5-2012

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Nutrition, Dietetics, and Food Sciences

Committee Chair(s)

Brian A. Nummer

Committee

Brian A. Nummer

Committee

Daren P. Cornforth

Committee

Marie K. Walsh

Committee

Silvana Martini

Committee

Bruce Miller

Abstract

Most outbreaks of foodborne illness in the United States occur as a result of improper food-handling and preparation practices in homes or food establishments. The lack of food-safety knowledge is one of the several reasons for this. However, researchers also suggest that food-operators and consumers with adequate food-safety knowledge, attitudes, and intentions do not always follow the food-safety recommendations because not all recommendations are easy to put into practice. Therefore, the first part of this study sought to establish safe alternative processing of meat products that can be easily practiced by food-operators and consumers. In Chapter 3, a novel method was developed to thaw frozen chicken breast by submersion in hot water at 60 °C. This is an appropriate temperature setting for foodservice hot-holding equipment. This method is rapid (compared to either refrigerator or cold-water thawing that also uses lots of water), safe, and the final cooked-product sensory-quality was not different from refrigerator-thawed and cooked product (microwave thawing results in localized overheating potentially lowering sensory quality). Chapter 4 developed a marinade-cooking (91 °C) and holding (60 °C) procedures of hamburger-patties. Frozen patties were partially grilled and finished cooking in marinade. The moderate temperature of marinade cooking overcomes the chances of thick-patties being surface-overcooked (quality defect) while innermost portions remain undercooked (temperature not sufficient enough to kill any harmful bacteria if present) as seen in high-temperature cooking methods such as grilling and pan-frying. Consumers liked the marinade-finished cooked and held patties (up-to 4 h) equally or more compared to patties grilled and held in hot-steam cabinet.

Reducing salt in perishable foods including cheese is a microbial-safety concern especially in their distribution and storage. The second part of this study (Chapter 5, 6) sought to evaluate the microbial safety of low-salt hard-type cheese. Aged Cheddar cheeses were inoculated with either Listeria monocytogenes or Salmonella spp. and their survival or growth was monitored at 4, 10, and 21°C for up-to 90, 90, and 30 d, respectively. Low-salt (0.7% NaCl) Cheddar exhibited no-growth or gradual reduction in L. monocytogenes and Salmonella counts. The results suggest that low- or reduced-salt cheeses are as safe as their full-salt counterparts (1.8% NaCl) and that salt may only be a minor food-safety hurdle regarding the post-aging contamination and growth of L. monocytogenes and Salmonella spp. However, as none of the treatments resulted in a complete kill of these pathogens, the need for good sanitation practice exists.

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Comments

This work made publicly available electronically on April 10, 2012.

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