It is estimated that 52 Americans die each year from exposure to the microbe. As many as 60,000 to 70,000 others are sickened from it annually.
Exposure usually comes from undercooked ground beef.
Each batch of ground beef tested by the USDA contained as much as 3,000 pounds of meat. Only trace amounts of the bacteria were found. But under the right conditions, bacteria can multiply rapidly. Consumer groups are calling for more thorough testing throughout the slaughter and processing of beef to control and reduce the contamination. The ground beef study comes on the heels of an earlier USDA study that showed up to 50 percent of cattle in feedlots may be contaminated with E. coli during certain times of the year.