Recent reports show E. coli appearing on fruits and vegetables. There aren't many long-term studies on the effects of E. coli and gardening. According to Cornell University horticulturist Stephen Reiners, E. coli typically is killed by summertime temperatures but remains viable under cooler conditions for as long as 77 days in slurry, and for as long as 100 days in manure-fertilized soil. Fortunately, most gardeners apply manure in the late fall or early spring, giving ample time for the E. coli to die. Bacteria also need a moist environment to remain alive.
Dry conditions hasten their death.
Nancy Pataky, Plant Pathologist with the University of Illinois, questions whether the E. coli bacteria would infect plants. E. coli, as non-traditional soil bacteria, would not be an aggressive invader. In fact, the other bacteria and fungi may actually feed on it. Additionally, no research has indicated that the E. coli bacterium is anything more than a surface contaminant. Caution, though, should always be the key word when using manure around edible crops.