Purpose: This study evaluated effects of acidified peroxyacetic acid (PAA) on Escherichia coli populations inoculated onto beef trimmings and head meat, and its effect on natural microflora and color of ground beef from treated trimmings.
Methods: In phase I, trimmings and head meat (n=5) were separately inoculated (6-7 log CFU/g) with a five-strain mixture of non-pathogenic E. coli. Samples were spray-treated (10-s) with PAA (345-360 ppm), a sulfuric acid+sodium sulfate blend (SSS; pH 1.0 or 1.2), PAA (345-360 ppm) acidified with SSS (aPAA; pH 1.0 or 1.2), lactic acid (LA; 4%), or water. Untreated (control) and treated samples were analyzed for Enterobacteriaceae (EB) counts. In phase II, uninoculated trimmings (n=5) were spray-treated with the same treatments, except water, and were then ground (with and without antioxidant addition), packaged under modified atmosphere (MAP), stored (0°C, 21 days), and then placed in simulated retail display (0-4°C, 5 days). Ground beef samples were analyzed for aerobic plate counts (APC), and objective and subjective color characteristics were obtained during retail display.
Results: The most effective (P<0.05) spray treatment against inoculated EB populations on trimmings was aPAA, with 0.6 log CFU/g lower counts than those of the control. Surviving inoculated populations on antimicrobially-treated head meat were not (P>0.05) different to those of water-treated samples. In phase II, LA- and aPAA-treated ground beef stored for 21 days under MAP conditions had APC that were 3.0 and 2.7 log CFU/g lower (P<0.05), respectively, than those of control samples. Trained panelists scored aPAA-treated ground beef most similar (P>0.05) in redness and discoloration to that of the control through day-3 of retail display.
Significance: With appropriate application, aPAA can be an effective alternative to LA for improved shelf-life of ground beef.