P1-211 Efficacy of Peracetic Acid Washes Applied at Increasing Concentrations to Control Shiga Toxin-producing Escherichia coli Contamination on Chilled Beef Subprimals

Monday, July 10, 2017
Exhibit Hall (Tampa Convention Center)
Matthew Krug , Kansas State University , Manhattan , KS
Sarah Jones , Kansas State University , Manhattan , KS
Nicholas Sevart , Kansas State University , Manhattan , KS
Jennifer Acuff , Kansas State University , Manhattan , KS
Amanda Wilder , Kansas State University , Manhattan , KS
Minto Michael , Kansas State University , Manhattan , KS
Christopher Vahl , Kansas State University, Department of Statistics , Manhattan , KS
Randall Phebus , Kansas State University , Manhattan , KS
Introduction: Shiga toxin-producing E. coli (STEC) are bacteria commonly associated with foodborne disease outbreaks, especially attributable to beef. Evaluation of intervention methods is necessary to better control these pathogens in the beef industry.

Purpose: This study validated the efficacy of increasing concentrations of a peracetic acid applied as a spray (PAA; Microtox Plus, ZEE Company) prior to chilled subprimal packaging for reducing populations of STEC. Impact on raw beef color was documented.

Methods: Ten beef strip loins were inoculated to ca. 5 log CFU/cm2 with a 7-serogroup (O157:H7, O26, O45, O103, O111, O121, O145) cocktail of rifampicin-resistant STEC. After 30-min attachment, subprimals were sprayed with PAA at increasing concentrations from 200–1800 ppm (at 200 ppm intervals) or a water control (0 ppm) before being vacuum packaged and stored for 24 h at 4°C. Excised tissue samples were taken from the top and bottom of each subprimal and microbiologically analyzed to quantify STEC reductions and L, a*, and b* color measurements were taken from the sides of the subprimals at three sampling points: post-inoculation, 5 min post-PAA spray, and post-24 h vacuum packaged chilling.

Results: Post-PAA treatments, STEC populations decreased by 0.5–1.3 log CFU/cm2 across all concentrations, which were different (P ≤ 0.05) than the water control (0.1 log CFU/cm2 reduction). No differences (P > 0.05) were observed among application of concentrations between 400–800 ppm. STEC populations did not change (P > 0.05) in the PAA-treated subprimals after 24 h of chilled vacuum packaged storage. Although subprimal color changed over time, no difference (> 0.05) was seen in color readings among PAA treatments of increasing concentrations.

Significance: These data suggest that a wide range of peracetic acid concentrations (≥ 400 ppm) will significantly reduce STEC on chilled beef subprimals, while having no effect on raw product color.