P1-210 Efficacy of an Ambient Water Wash, Hot Water Wash, and Application of Three Antimicrobial Sprays Using a Three-stage Commercial Carcass Washing Cabinet for Reducing Shiga Toxin-producing Escherichia coli Contamination on Beef Carcasses

Monday, July 10, 2017
Exhibit Hall (Tampa Convention Center)
Matthew Krug , Kansas State University , Manhattan , KS
Jennifer Acuff , Kansas State University , Manhattan , KS
Nicholas Sevart , Kansas State University , Manhattan , KS
Minto Michael , Kansas State University , Manhattan , KS
Daniel Vega , Kansas State University , Manhattan , KS
Christopher Vahl , Kansas State University, Department of Statistics , Manhattan , KS
Gary Acuff , Texas A&M University , College Station , TX
Harshavardhan Thippareddi , University of Georgia , Athens , GA
Randall Phebus , Kansas State University , Manhattan , KS
Introduction:  Shiga toxin-producing Escherichia coli (STEC) associated with live cattle pose a risk for beef contamination during slaughter. To control these risks, beef carcass intervention methods are widely implemented across the industry.

Purpose:  The antimicrobial effectiveness of intervention methods applied sequentially to pre-rigor beef carcass sides, using a three-stage commercial spray cabinet (Chad Equipment) to reduce STEC contamination, was evaluated.

Methods:  Four pre-rigor carcass sides were inoculated by electrostatic spraying with a 7-serogroup STEC cocktail (ca. 6 log CFU/100 cm2). The following treatments were applied, in order, to each side in the cabinet: ambient water wash, hot water wash, and antimicrobial mist. Each side was assigned one of four chemical treatments: no treatment (control), peracetic acid (200 ppm), lactic acid (4.5%), or Centron™ (1.1 pH). Excision samples were taken from the top, middle, and bottom region of each side at: 30 min post-inoculation, post-ambient water wash, post-hot water wash, post-antimicrobial spray, and after 18 h spray chilling (three replications conducted).

Results:  The cabinet’s ambient water stage reduced the STEC population on sides by 0.9, 1.1, and 1.5 log CFU/100 cm2 and the hot water stage, additionally, by 2.6, 3.6, and 3.3 log CFU/100 cm2 at the bottom, middle, and top of the carcass, respectively. Although the STEC reduction observed at the top of the carcass was higher (≤ 0.05) than the bottom for ambient water, no differences (> 0.05) among sampling locations were observed at the other sampling points. Minimal additional STEC reductions were obtained after chemical spray application and chilling, due to STEC contamination reaching very low or undetectable levels with the post-hot water wash.

Significance:  Sequential antimicrobial treatments applied using a carcass wash cabinet (ambient and hot water washes, followed by approved chemical sprays) reduced STEC populations on pre-rigor beef carcasses by 4.5–5.3 log CFU/100 cm2; significantly reducing STEC risks on fabricated beef products.