Dispersion and survival of Escherichia coli O157:H7 and Salmonella Typhimurium during the production of marinated beef inside skirt steaks and tri-tip roasts

To determine the depth of pathogen dispersion and the ability of pathogens to survive in enhanced beef products and spent marinade, beef inside skirt steaks and tri-tip roasts were vacuum tumbled with two commercial marinades. The marinades were inoculated with Escherichia coli O157:H7 and Salmonella Typhimurium, resulting in an approximate count of 5.2 log CFU/ml. Both inside skirt steaks and tri-tip roasts were vacuum tumbled for 1 h and sampled immediately after tumbling (day 0), or were vacuum packaged, stored (ca. 4°C), and sampled on days 7 and 14. Samples of the spent marinade were taken after tumbling (day 0) and on days 3 and 7. For both marinades, Salmonella Typhimurium and E. coli O157:H7 were dispersed throughout the inside skirt steaks during vacuum tumbling. Although Salmonella Typhimurium and E. coli O157:H7 for the skirt steaks were still detectable after 14 days of storage, the log values were lower than those on days 0 and 7. For the tri-tip roasts, the pathogen distribution varied, depending on the thickness of the roasts, and pathogens were detectable on days 0, 7, and 14. The spent marinade sampled on days 0, 3, and 7 showed that the pathogens survived at refrigerated temperatures. Because pathogens can transfer to the interior of beef inside skirt steaks and tri-tip roasts when vacuum tumbled with contaminated marinade and survived during refrigerated storage, establishments should consider the potential food safety risks associated with reuse of marinade during the production of vacuum-tumbled beef products.