It takes E. coli one to 10 days to incubate before symptoms become present, so public health officials believe more cases could still develop in the St. Louis area.A week into their investigation, public health officials are stressing there is no evidence linking an E. coli outbreak in the St. Louis area to salad bars at Schnucks Markets.
Even though some of the 35 people in the St. Louis area who have fallen ill say they ate food from various Schnucks Markets salad bars before becoming sick, health officials say they are still looking at a wide variety of possible contamination sources.
No one has died, but nine people have been admitted to area hospitals.
St. Louis media reports that officials are focusing on the Schnucks salad bars are worded “a little strong,” John Shelton, St. Louis County Health Department spokesman, said on Nov. 1.
“Some patients have said that they ate there but none of the tests (from Schnucks) have come back positive,” Shelton said.
In an Oct. 31 news release, Schnucks officials said the company’s food safety team had recommended swift preemptive action just in case. “All items in question” have been removed from the chain’s salad bars, according to the release. Schnucks operates 66 stores in St. Louis and surrounding areas.
Shelton said public health investigators from the county, state and federal Centers for Disease Control and Prevention are interviewing the sick people to try to find a common thread linking them.
Four staffers from the CDC arrived in St. Louis Oct. 28 to help with the investigation, which spans the metro area in addition to St. Charles, Jefferson and St. Louis counties in Missouri and St. Claire County in Illinois.
“The interviews take more than an hour with each person,” Shelton said. “It is a 37-page questionnaire.”
“Once we heard that the health department had declared an outbreak, we took some proactive steps with our food safety team to switch products out that recent history told us could be potential sources,” Schnucks spokeswoman Lori Willis said Oct. 28.
Different Schnucks locations took different precautions. One location pulled strawberries, lettuce and croutons out of its salad bar on Oct. 26. A downtown St. Louis Schnucks had already pulled some fresh-cut lettuce products because of an unrelated recall and posted a sign reassuring customers that its salad bar does not use lettuce involved in the recall.
Health officials became concerned Oct. 24 when multiple reports of E. coli started coming in. For the entire year of 2010 St. Louis County had only five reported cases of E. coli. Officials expect more people to become sick because the incubation time between exposure and onset of symptoms can be from one to 10 days.
About two dozen lab tests done so far show that samples from infected people and other sources, such food from their homes, have shiga toxin present. Shiga toxin is a byproduct from E. coli and generally indicates the pathogen is present. Specific tests for E. coli take several days in the lab before conclusive results are available. Tests are being conducted at the Missouri State Health Department laboratory.