REDUCTION OF LISTERIA-MONOCYTOGENES, ESCHERICHIA-COLI O157-H7 AND SALMONELLA-TYPHIMURIUM DURING STORAGE ON BEEF SANITIZED WITH FUMARIC, ACETIC, AND LACTIC ACIDS

Cylindrical samples of beef semitendinosus muscle were dipped into an inoculum of listeria monocytogenes, Escherichia coli O157: H7, and Salmonella typhimurium. After air drying for 10 min, samples were sanitized by dipping in fumaric acid (1.0 or 1.5%), lactic acid (1%) or acetic acid (1.0%) solutions for 15 or 30 s at 550. The 1.5% fumaric acid was most inhibitory against L. monocytogenes, resulting in inactivation of this pathogen after 7 days of storage. Samples treated with 1.0% and 1.5% fumaric acid solutions for 30 sec gave 2.54 and 1.51 log(10) reductions, respectively, in S. typhimurium population compared to nontreated samples. The 1.5% fumaric acid treatments for 30 s exerted the maximum inhibition of E. coli O157:7. Acetic and lactic acid treatments were significantly less effective in reducing populations of the tested pathogens than fumaric acid treatments. As the sanitizing time in acid solutions increased from 15 to 30 s, the numbers of surviving organisms were reduced significantly.