USDA-FSIS recently updated their data on E. coli O157:H7 in ground beef and trim through July 8, 2012 (http://www.fsis.usda.gov/Science/RGBC_STEC_Results/index.asp). In order to get a visual representation of the risk associated with ground beef, the year-end results were plotted. Only routine samples were evaluated for ground beef (both federal plant and retail). Based upon this sampling, E. coli O157:H7 is found in approximately 0.1% to 0.2% of ground beef samples.
This rate is a lower than the percent positive found in trim (beef trim that goes into ground beef). For 2011, trim verification yielded a 0.64% positive and thru 7/2012, 0.53%.
The results indicate that interventions put in place by the meat industry have had an impact in reducing the level of E. coli in ground beef, however, from a consumer's perspective, careful handling and preparation is required. Specifically, cleaning hands and food contact surfaces when handling and preparing, and cooking to the proper internal temperature of 160ºF.