SURVIVAL OF SALMONELLA-TYPHIMURIUM, ESCHERICHIA-COLI O157-H7 AND LISTERIA-MONOCYTOGENES DURING STORAGE ON BEEF SANITIZED WITH ORGANIC-ACIDS

Sterile beef tissue was inoculated with either Salmonella typhimurium, Escherichia coli O157:H7 or Listeria monocytogenes Scott A and washed with 23C distilled water, 1% lactic acid or 1% acetic acid. The washed tissue was subjected to simulated dry chilling or spray chilling followed by storage at 5C. The washed tissue was stored at 5C for up to 21 days at 26% relative humidity, and total bacterial populations were determined by plating on nonselective and selective agars. There was no significant difference in the surviving populations of S. typhimurium, Escherichia coli O157:H7, or L. monocytogenes after storage, irrespective of chilling method. The surviving populations of bacteria were significantly lower on acid washed adipose tissue, when compared to the comparable water washed tissue. These results indicate that although injury and recovery of pathogenic bacteria may occur as a result of organic acid carcass sanitizing treatments, there was no practical significance of this phenomenon after 3 days of storage.