Title

Bacterial Abundance and Resistance in Ground Beef Varieties

Date

5-31-2018 10:00 AM

End Time

31-5-2018 10:20 AM

Location

HWC 105

Session Chair

Jeff Snyder

Session Chair

Arlene Courtney

Session Title

Natural Sciences presentations

Presentation Type

Presentation

Faculty Sponsor(s)

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). Regular beef contained 14 times more fecal E. coli and 8 times more fecal Hafnia-like bacteria than organic beef. Pseudomonas was only isolated from organic beef. This procedure was repeated using MacConkey plates containing commonly used agricultural antibacterial drugs to assess the prevalence and types of drug-resistant bacteria. Preliminary results show no tetracycline or kanamycin resistance in either ground beef source. Extensive penicillin, sulfamethazone, cefazolin and ampicillin resistance was retrieved from regular beef- but not organic.

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May 31st, 10:00 AM May 31st, 10:20 AM

Bacterial Abundance and Resistance in Ground Beef Varieties

HWC 105

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). Regular beef contained 14 times more fecal E. coli and 8 times more fecal Hafnia-like bacteria than organic beef. Pseudomonas was only isolated from organic beef. This procedure was repeated using MacConkey plates containing commonly used agricultural antibacterial drugs to assess the prevalence and types of drug-resistant bacteria. Preliminary results show no tetracycline or kanamycin resistance in either ground beef source. Extensive penicillin, sulfamethazone, cefazolin and ampicillin resistance was retrieved from regular beef- but not organic.