The St. Louis region's largest grocery chain is removing some items from its salad bar amid concerns about E. coli, even though investigators still don't know the cause of the outbreak.

Health officials say nearly two dozen people have been sickened by the illness in St. Louis city and four surrounding counties.

Investigators from the state of Missouri and the U.S. Centers for Disease Control and Prevention are in St. Louis to try and determine the cause.

Lori Willis of Schnuck Markets Inc. says the removal of some items is strictly precautionary. Representatives from the region's other big grocers - Dierberg Markets Inc. and Shop 'n Save - say they have not removed any items because they have no indication of the possible culprit.

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