The discovery of \o7E. coli \f7in Salinas Valley irrigation water used on a lettuce crop indicates that fecal bacteria is widespread in the environment but offers no new insight into the contaminated spinach that has sickened nearly 200 people, food safety experts said Monday.
Nunes Co. of Salinas, Calif., voluntarily recalled more than 8,500 cartons of green-leaf lettuce Sunday after discovering \o7E. coli \f7in irrigation water used on the crop. The water came from a farm's deep wells but had been stored in a reservoir before it was pumped into the farm's irrigation system.
Most \o7E. coli \f7bacteria are not harmful to humans and, in fact, are found in the stomachs of people as well as other mammals and birds. The bacterium identified in the lettuce irrigation water was this generic form of \o7E. coli, \f7which is common in water and soil around the world.
Further testing will show whether the water also contained a virulent strain of \o7E. coli, \f7known as O157:H7, that sickened people who ate spinach grown in the Salinas Valley, Food and Drug Administration officials said. Of 199 people who fell ill in the spinach outbreak, 102 were hospitalized and three died.
The type of \o7E. \f7\o7coli \f7in the water used on the recalled lettuce is found in the feces of every warm-blooded animal, said Dean Cliver, a food safety professor at UC Davis. "It typically does no harm but is used as an indicator of fecal contamination," Cliver said. "Unless it was present in unusually high levels, it probably did not indicate a threat to consumer health."
Water from that reservoir apparently does not share a common source with water supplies used on the region's spinach and other crops.
"Currently there is no link between the Nunes Co. and the previous spinach outbreak," said David Acheson, chief medical officer at the FDA's food safety center.
Food safety experts say Nunes Co.'s recall indicates growers in the region are being very cautious in light of the spinach outbreak.
Acheson praised the company for taking preventive action and recalling the lettuce despite the lack of evidence of a health threat. "We do not have an outbreak. We have a recall of lettuce that may be contaminated with generic \o7E. coli," \f7Acheson said.
"At this stage we don't know whether the \o7E. coli \f7found in the irrigation water contains any harmful \o7E. coli \f7to humans," he added.
