ANTIMICROBIAL INTERVENTIONS APPLIED TO BEEF SUB-PRIMALS FOR THE CONTROL OF ESCHERICHIA COLI AND THEIR IMPACT ON GROUND BEEF QUALITY

Authors

Kelly Ann McCarty, University of Nebraska-LincolnFollow

First Advisor

Dennis E. Burson

Date of this Version

12-2016

Document Type

Article

Citation

McCarty, K. A. 2016. Antimicrobial Interventions Applied to Beef Sub-Primals for the Control of Escherchia coli and Their Impact on Ground Beef Quality. University of Nebraska-Lincoln Thesis.

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science Major: Animal Science Under the Supervision of Professor Dennis E. Burson Lincoln, Nebraska December, 2016

Copyright 2016 Kelly Ann McCarty

Abstract

Due to their severe health implications, seven shiga toxin-producing E. coli (STEC) serotypes were declared adulterants by USDA-FSIS in raw, non-intact beef products. Small business beef processing facilities are being asked to implement an intervention on the beef sub-primals and trim they receive for ground beef production. This study evaluates the efficacy of reducing rifampicin-resistant E. coli (E. coli^Rif) using 4.5% lactic acid (LA), 2.5% Beefxide™ (BX), and 380 ppm peroxyacetic acid (PAA) when applied by dip, spray or electrostatic spray (ESS) to the mostly fat lateral surface and mostly lean medial surface of beef shoulder clods (IMPS 114) and compared to an inoculated control on reducing the presence of E. coli^Rif on beef sub-primals meant for ground beef. All organic acid treatments had a greater reduction (P < 0.01) than the inoculated control using E. coli petrifilm. However, when using APC petrifilm, all ESS treatments were similar (P > 0.05) to the control. In addition, LA had greater (P < 0.05) E. coli^Rif reductions on E. coli petrifilm than BX treatments. PAA had greater (P < 0.05) E. coli^Rifreductions using APC petrifilms than BX. Ground beef samples from electrostatic spray treatments had similar reductions (P > 0.05) to that of the inoculated control and had lower reductions (P < 0.001) than the dip or spray methods. A second study was designed to determine the effects of the same acids and application methods on ground beef quality. Ground beef samples from the PAA spray were darker (P < 0.05) than the control, PAA dip and electrostatic spray, BX spray and electrostatic spray, and LA spray. In addition, LA electrostatic spray was less yellow (P < 0.01) than the control and BX dip and spray treatments. When looking at APC counts, LA electrostatic spray had higher CFU/g than PAA spray and dip, BX spray and electrostatic spray, and LA dip. TBARS values showed that LA treatments had greater (P < 0.01) oxidation than PAA treatments. LA dip and electrostatic and BX spray had lower (P < 0.001) pH values compared to the control. All treatments reduced E. coli^Rif counts and had minimal effects on quality attributes.

Advisor: Dennis E. Burson