More bags of spinach tainted with toxic E. coli bacteria have been found and could help investigators track down an outbreak that may have killed three people, the U.S. Centers for Disease Control and Prevention said Tuesday.
Investigators found the bags in Pennsylvania, Illinois, and Ohio. The CDC said the DNA "fingerprint" of the strain isolated in Pennsylvania matches that of the outbreak strain.
"'DNA fingerprinting' is underway on the strains isolated in Illinois and Ohio," the CDC said in a statement.
It said 183 people in 26 states had been confirmed with E. coli O157:H7 infections in the outbreak.
The Toronto Star newspaper said a woman in Canada's Ontario province had also been infected.
At least one person has died in the outbreak, in Wisconsin, and state health officials were checking the cases of a 2-year-old boy who died in Idaho and an 86-year-old woman who died in Maryland, both reportedly after eating spinach.
Escherichia coli is a usually harmless bacteria normally resident in the guts of animals, including humans. A new and pathogenic strain called E. coli O157:H7 was identified in 1982 and it now causes an 73,000 cases of infection and 61 deaths in the United States each year.
Most illness has been associated with undercooked, contaminated ground beef. But if contaminated manure gets into irrigation water or is used in fertilizer, it can get onto fresh produce or into the water supply.
Environmental groups said large-scale farming and poor regulation by the Environmental Protection Agency, the Food and Drug Administration and the U.S. Department of Agriculture were to blame for the outbreak.
"Factory farms are a major source of E.coli contamination, but the EPA is not doing enough to protect our food or water supplies," said Melanie Shepherdson of the Natural Resources Defense Council.
"These factory farms generate some 500 million tons of manure annually, and routinely over-apply the liquid waste on land. It then runs off fields into nearby streams or seeps into underground water supplies, polluting the water with viruses, bacteria, pesticides, antibiotics, hormones and excessive nutrients," the NRDC added in a statement.
"We have the technology to significantly reduce the bacteria, viruses and parasites in factory farm animal waste. We shouldn't have to worry about eating contaminated vegetables or drinking water."
The NRDC, the Sierra Club and the Environmental Integrity Project sent out joint releases saying they were meeting with EPA officials with their complaints.
"In the case of the E. coli contamination of spinach, state authorities notified the Food and Drug Administration on August 23 that individuals had become ill; but it took the FDA until September 14 to warn the public," the NRDC said.
"Even now, more than a month after learning of the E. coli poisoning, FDA has yet to take any enforcement action."
The FDA has experts on a team of 20 inspectors looking at farms in three California counties where the outbreak seems to have originated. FDA officials have said tighter regulations of such farms may be necessary.