Date of Award:


Document Type:


Degree Name:

Doctor of Philosophy (PhD)


Nutrition, Dietetics, and Food Sciences

Committee Chair(s)

Brian A. Nummer


Brian A. Nummer


Marie K. Walsh


Luis Bastarrachea


Karin Allen


Michael Pate


This study evaluated microbial safety of relatively new and modified food products prepared especially by small-scale foodservice establishments and home producers. In the first part, microbial safety during fermentation at room temperature was evaluated. Chapter 3 monitored Listeria monocytogenes and Escherichia coli O157 survival during Sauerkraut’s natural fermentation. Chapter 4 evaluated the survival of acid-adapted E.coli O157 during kombucha fermentation and in kombucha-fruit blend during refrigeration. During both fermentations, the pathogens were inactivated before the recommended duration of fermentation. However, E.coli O157 introduced after fermentation survived in kombucha-fruit blends during refrigerated storage. The second part (Chapter 5) evaluated the safety of commercial and lab-prepared fry sauce by monitoring the survival of acid-adapted E. coli O157, L. monocytogenes, and Salmonella at room temperature and refrigerated storage. The pathogens survived longer under refrigeration in the treatments in comparison to storage at room temperature. Inverse relationship of pH and pathogen reduction were observed more prominently at refrigerated storage. The third part (Chapter 6) assessed the survival of L. monocytogenes in commercial cold-brewed coffee under refrigeration. 18 ready-to-drink and concentrate samples were monitored for the survival of inoculated L. monocytogenes for 60d. The pathogen was undetectable within 60 d in 10 samples, whereas the pathogen survived in the remaining 8 samples. The last part of the study (Chapter 7) assessed the survival of E. coli O157, L. monocytogenes, and Salmonella in 10, 20, 30, 40, and 50% ethanol and juice mixtures at ambient temperature for 48 h. The pathogens did not survive in the mixture of juice and ethanol at 40 or 50% after 48 hours. In the mixtures prepared with 10-30% ethanol and juice, the decrease in pathogen was variable between the pathogen itself and the juice evaluated, with some demonstrating survival after 48 h. The study's finding does not imply that the products evaluated in this study and other similar products can be made without individual product evaluation.



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