ST. LOUIS COUNTY, Mo. — Lettuce tested from a St. Louis County banquet and catering facility has come back negative for E. coli, but the St. Louis County Department of Health (DPH) has not ruled out the business as the source.

Approximately 106 people became sick after attending five separate off-campus events earlier this month, including students, family and staff from Rockwood Summit High School and Oakville High School.

DPH named Andre’s Banquets and Catering as a link to the E. coli outbreak exposure before any food testing was done. Health officials suspect the salad served by the business may be the source of illness. 

The company’s owner says he has cooperated from the beginning and maintains that it is not responsible for the outbreak.

“While I am relieved to learn of the Missouri State Public Health Laboratory’s negative test results, I will continue to cooperate with the state and local health departments as they now work to determine the source of E. coli that has caused illnesses in the region and which has resulted in individuals who did not attend any events affiliated with Andre’s contracting E. coli,” the owner said in a statement. 

While the lettuce sampling came back negative, DPH says the test result does not rule out salad from the company as a potential source of the E. coli outbreak.

“This is because bacteria like E. coli often occur in isolated pockets within food products, making it possible for a sampling event to miss the pathogen entirely,” DPH said in a press release.

“A negative result does not necessarily indicate the absence of the bacteria or eliminate Andre’s as a potential source,” explained DPH.

DPH says that dozens of individuals with consistent, clinically compatible symptoms are all linked by the exposure to a salad from Andre’s.

“This shared exposure is highly significant and remains the strongest link to the outbreak, regardless of whether a specific contaminated ingredient is identified through testing,” DPH said in the press release.

The health department says it continues to build a “clearer picture of the contamination pathway” to prevent further cases. 

“This shared exposure is highly significant and remains the strongest link to the outbreak, regardless of whether a specific contaminated ingredient is identified through testing,” DPH said in the press release.

Two people among the E. coli outbreak have developed a rare and serious disease caused by the bacterial infection.

The investigation is ongoing by DPH.