Year of Publication

2019

Degree Name

Master of Science (MS)

Document Type

Master's Thesis

College

Agriculture, Food and Environment

Department

Animal and Food Sciences

First Advisor

Dr. Gregg Rentfrow

Abstract

The objective of this study was to evaluate the survival of non-O157:H7 STEC, Salmonella spp., and S. aureus in dry fermented sausages. Chorizo and Landjager sausages were inoculated with individual bacterial cocktails and stuffed into natural casings. Temperature, relative humidity, pH, and water activity were monitored through fermentation, drying, and storage. Bacterial counts were determined by serial dilution and plated in triplicates on selective media. Plates were incubated at 37°C for 24 hours and colony forming units per gram (CFU/g) were observed.

Results of the first study validate that contaminated raw materials contribute to pathogen survival and background bacteria outcompeted the starter culture. The pH critical limit of < 5.3 was met but there was no pathogen inhibition. Results from the second study confirm that pH and water activity are not enough to eliminate pathogens when post processing interventions are not used. Critical pH (< 5.3) and water activity (< 0.85) limits were met, but pathogens still survived.

In chorizo, non-O157:H7 was recovered through enrichments until the end of the study. In landjager, non-O157:H7 STEC and Salmonella were recovered through enrichments until the end of the study.The studies suggest that sausages produced without post processing interventions are a health risk to consumers.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2019.074

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