Over the weekend, federal health officials expanded their initial warning not to eat bagged spinach to include any fresh, raw spinach. As of late Saturday, the CDC reported 102 cases of E. coli exposure in 19 states, including one death in Wisconsin.

This latest incident, taken with earlier reports of E. coli contamination in greens, exposes a glaring weakness, experts say, and that effective health standards and cleanliness enforcement should be dependent on the farm itself. Currently, FDA enforcement authority begins in the packaging facilities where produce is washed and packaged for transport.

Consumer watchdogs hope the more-frequent appearance of E. coli in leafy vegetables will finally cause Congress to expand the reach of the Federal Drug Administration to farms.

Scientists say E. coli bacteria live in the intestines of cattle and other animals and are passed to plants through contact with fecal matter. Produce could become contaminated several ways: manure used for fertilizer, fecal runoff into streams that are used for farm irrigation, or even droppings from birds that had swallowed manure. As a result, many observers say that stricter FDA oversight is needed at sites where produce is grown.