Investigators were looking into a possible link between salad bars at a major grocery chain and 33 suspected E. coli cases in the St. Louis area, a state health official said Tuesday.
The Missouri Department of Health and Senior Services said 26 people have tested positive for the E. coli strain 0157:H7. Results of tests on seven other people were pending.
St. Louis County had just five cases of E. coli in all of 2010, county health department spokesman John Shelton said.
"We are calling this an outbreak, which is a word we don't throw around loosely," he said.
State health department spokeswoman Jacqueline Lapine said several of those who became ill had obtained food from salad bars at Schnucks Markets Inc., which operates 66 stores in the St. Louis area. Inspectors have tested food samples taken from lettuce, strawberries and Caesar dressing from those salad bars. All the tests so far were negative.
The Missouri state lab also tested strawberries taken from the home of someone who got sick. Those strawberries also tested negative.
More food testing is planned, Lapine said. Meanwhile, food safety investigators inspected Schnucks stores, warehouses and even food supplier facilities and found no conditions that would allow for E. coli, the state said.
Investigators have now asked the U.S. Food and Drug Administration to extend the investigation up the distribution chain, a move that could lead to inspections of distributors and food producers outside of Missouri, Lapine said.
Lapine said 20 of the people who became ill shopped at Schnucks stores, and 17 of them reported obtaining food from the salad bar. The stores were spread across the St. Louis region.
Illnesses have been reported in people ranging in age from 1 to 94 and live in St. Louis city and four surrounding counties _ St. Louis, Jefferson, St. Charles in Missouri and St. Clair County, Ill. None of the illnesses were considered life-threatening.
Schnucks spokeswoman Lori Willis said the chain is cooperating fully with investigators and has removed items that were potential causes.
"There is a correlation between Schnucks and this outbreak, but we won't know the scope until we can pinpoint a source," Willis said. "We are the seller of the product, but we didn't make those items on the salad bar."
It was too early to determine how news of the outbreak has affected sales at Schnucks, Willis said, but she noted that customers "have been very understanding and have accepted our information and explanation very graciously."
So far, no food items have been tested from other stores in the region, Lapine said.
E. coli are a group of bacteria that can cause diarrhea, urinary tract infections, respiratory illness and pneumonia. The illness is typically spread through consumption of contaminated food, unpasteurized milk, contaminated water or contact with the feces of infected people.
Young children and the elderly are most at risk of serious illness which can, in rare instances, be fatal. Health officials encouraged immediate medical attention for anyone with bloody or persistent diarrhea, severe stomach cramps or nausea
Health officials encourage people to wash hands thoroughly, especially after going to the bathroom; wash produce and cooking equipment; and cook all meats to at least 167 degrees, the level at which germs are killed.
Lapine said investigators with the state and the U.S. Centers for Disease Control and Prevention are interviewing patients to determine a "dietary history" in an effort to determine the source of contamination.