At least 30 people in four states have been sickened by a rare, virulent strain of E. coli in pre-shredded Romaine lettuce.
Some cases may have gone unreported because many labs do not test for the E. coli strain causing the outbreak. Michigan, Ohio, New York, and Tennessee have reported cases.
Lettuce harvested from other areas does not appear to be associated with the outbreak, the FDA investigation suggests.
The illnesses occurred between April 10 and April 26. Because of a lag time between the last reported illness and testing, it’s possible new illnesses may still be occurring.