Bacterial Abundance and Resistance in Ground Beef Varieties

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Title: Bacterial Abundance and Resistance in Ground Beef Varieties
Author: Savannah Kumar; Sarah M. Boomer
Faculty Sponsor: Sarah Boomer
Abstract: Raw ground beef purchased at supermarkets across America have one thing in common: they harbor bacteria, some of which are drug resistant and can be detrimental to public health. To understand the impact of farming and processing practices on the quantity of bacteria and drug resistance, organic and regular beef were assessed using MacConkey media. Bacterial colonies were sorted according to lactose utilization, with positive colonies representing fecal E. coli. Lactose negative colonies were further characterized into one of two groups (fecal Hafnia-like or soil Pseudomonas) using a variety of metabolic tests (oxidase, sulfur, indole). Advanced metabolic testing showed that regular beef contained significantly more fecal E. coli-like bacteria, Hafnia-like bacteria and fecal Providencia-like bacteria than organic beef. Soil Pseudomonas was only isolated from regular beef. This procedure was repeated using MacConkey plates containing commonly used agricultural antibacterial drugs to assess the prevalence and types of drug-resistant bacteria. Bacteria resistant to penicillin, sulfamethazine, cefazolin, or ampicillin were found at significantly higher levels on regular beef than organic. Bacteria resistant to more than one of these drugs were only found on regular beef.
Description: I would like to thank the Kenneth M. Walker Undergraduate Research Award for the financial support which provided all culture-based research supplies, antibiotics, and DNA analysis services used for this project. I would also like to thank Western Oregon University for the lab space used to research our topic and Sarah Boomer for the unwavering support and guidance throughout this process. Finally, I would also like to thank Western Oregon University’s Academic Excellence Showcase and The Oregon Academy of Science for the platform on which to share my research.
Subject: Bacteria; Bacterial Infections and Mycoses; Bacteriology; Food Microbiology; Large or Food Animal and Equine Medicine; Microbiology; Pathogenic Microbiology; Public Health Education and Promotion; Ground beef; antibiotic resistance; E. coli; Pseudomonas; food safety; MacConkey
Rights: http://creativecommons.org/licenses/by-nd/4.0/
License: http://creativecommons.org/licenses/by-nd/4.0/
Type: Text
volume: 7
Date Published: 11/26/2018
Note: Sarah Boomer
Alternative Title: Bacterial Abundance and Resistance in Ground Beef Varieties
Identifier: pure/vol7/iss1/6
Language: eng