The FDA has ended its investigation into one of two mystery Listeria outbreaks that have been ongoing for several months. The agency conducted a traceback investigation, an on-site inspection, and testing on samples of the suspected food source, but closed the investigation saying “there is not enough evidence to identify a vehicle.”

The outbreak includes 20 patients who first experienced symptoms on dates ranging from late 2021 or earlier to April 20, 2022. But that number may yet increase as Listeria symptoms can take as long as 70 days to develop.

The U.S. Food and Drug Administration (FDA) charts the progress of its food poisoning outbreak investigations on a table it updates each week.  (The U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA FSIS) has a  less detailed chart that it updates each week.) The FDA assigns reference numbers to these investigations.  The number for this outbreak, 1040, means this investigation began right after the Fresh Express salad Listeria outbreak investigation, reference number 1039, and before the Dole salad Listeria outbreak investigation, reference number 1048. The FDA and the CDC announced both of those outbreaks in late December 2021.

Both the Dole and Fresh Express Express outbreaks included cases over multiple years so it’s possible that outbreak 1040 also included illnesses that occurred even earlier than late 2021. The FDA has not provided enough information to be clear on that point.

Bagged salad outbreak image from CDC

The remaining mystery/unsolved Listeria outbreak has the reference number 1057 meaning this investigation was opened right after the FDA began investigating complaints about infants who became ill after consuming Similac powdered infant formula in early January 2022.

This outbreak includes 19 patients.

Symptoms of a Listeria Infection

Symptoms of a Listeria infection include high fever, severe headache, stiff neck, other muscle stiffness, nausea, abdominal pain, diarrhea, confusion, loss of balance, and convulsions. Among pregnant women, Listeria infections can suffer miscarriage or stillbirth even if the symptoms they experience are mild.

Experienced Listeria Lawyers

If you developed a Listeria infection and would like to discuss your legal options, please contact our Listeria lawyers. You can reach us by calling 1-888-377-8900, sending a text to 612-261-0856, or by completing the form below. There is no obligation and we don’t get paid unless we win.