Pounds of beef and E. coli O157 are joint products in the feedlot industry, according to the Impact Center E-Newsletter. "The level of E. coli naturally occurring in beef is not necessarily harmful," said Washington State University researcher Tom Marsh. "It is when these levels go up dramatically that an increased likelihood of an outbreak occurs."

“It is ideal to identify those practices in the feedlot that increase cattle performance and decrease E. coli prevalence,” said Marsh. “Controlling insects and rodents, as well as manure management, are strategies that were significantly associated with reduced E. coli and increased profit level.”

While feedlot managers may not have an incentive to keep E. coli out of their herds, spinach farmers have an incentive to keep E. coli out of their fields.