Effects of heat and acid stress on bacterial populations of beef, and on susceptible and multi-antimicrobial resistant Salmonella isolated from beef

Studies were conducted to serve as initial investigations evaluating antimicrobial efficacies of decontamination treatments applied to beef carcass tissue following chilling, prevalence of susceptible and antimicrobial resistant Salmonella on beef animal hides and carcasses, and whether antimicrobial resistance provided cross-protection against low-pH or heat stress. Results of studies evaluating methods to improve microbiological quality of chilled beef carcasses, subprimal cuts, and fabrication table surfaces, suggested reduced antimicrobial efficacy (≤ 1 log CFU/100 cm2 reduction) of steam-vacuuming and lactic acid solution rinsing when applied during beef carcass fabrication. Study results also supported concerns regarding increased antimicrobial resistance among foodborne bacterial populations, as data indicated that 10.7% of beef animal hide samples contained Salmonella resistant to at least one of thirteen antimicrobials screened. Salmonella isolated from beef animal hides and carcasses were used to evaluate acid and heat tolerance among susceptible and multi-antimicrobial resistant strains. Under the conditions of these studies, results comparing the stress resistance between susceptible and multi-antimicrobial resistant Salmonella, following preparation under acid tolerance-inducing and noninducing conditions, suggested that previous induction of a stationary-phase acid tolerance response afforded increased acid and heat resistance. However, the ability of Salmonella to avoid or repair damage associated with low-pH or thermal stress appeared to be independent of antimicrobial susceptibility.

Name thesis:degree_name

Doctor of Philosophy (Ph.D.)

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Animal Sciences

Grantor dc:publisher

Colorado State University. Libraries

Year dc:date.issued

2002

Authors dc:creator

• Bacon, Richard Todd, author
• Sofos, John N., advisor
• Smith, Gary C., committee member
• Belk, Keith E., committee member
• Hyatt, Doreene R., committee member

• microbiology

Statement dc:rights

• Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.

Language dc:language.iso

eng, English

Identifier URI

https://doi.org/10.25675/3.027043

OAI identifier oai:identifier

oai:mountainscholar.org:10217/244594