The U.S. Food and Drug Administration (FDA) is investigating two “mystery” Listeria outbreaks. Not much information, not even a suspected food source, is publicly available even though both investigations have been ongoing for months.


Some people may find this odd considering that, in both cases, the FDA has enough information about the product to conduct a “traceback investigation.”  This means that during interviews with health officials, people who got sick named a common food source and where they purchased it and the FDA began tracing the product’s journey back through the supply chain from the store or restaurant where it was purchased to the source to see where the contamination occurred.

So, the FDA actually has a fair amount of information about these outbreaks. The only mystery is to consumers who haven’t been told the type of product that has made people sick, the brand name(s), the stores or restaurants where it was sold, or if it is still on the market.

Listeria is a leading cause of hospitalizations and deaths from foodborne illness. More than 90 percent of cases require hospitalization. And about 16 percent of cases are fatal. Pregnant women are at high risk for these infections and can suffer miscarriage or stillbirth even if they only experience mild symptoms.

Symptoms of a Listeria infection, including high fever, severe headache, stiff neck, other muscle stiffness, nausea, abdominal pain, and diarrhea, can take as long as 70 days to develop. So, a consumer who ate whatever the FDA announced it was investigating in February might just be beginning to feel sick.

Here’s what we do know.

Listeria Outbreak 1

On February 9, 2022, the FDA announced its investigation of the first mystery Listeria outbreak. Since that time, the agency has conducted a traceback investigation and an on-site inspection, collected samples of the suspected food product, and began testing them. The outbreak has sickened 17 people.

According to the FDA’s reference number for this outbreak, 1040, 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. Both of those outbreaks were announced by the FDA and the CDC in late December 2021.

The Fresh Express salad Listeria outbreak sickened 10 people in eight states. All of the patients were hospitalized, one person died. The Dole salad Listeria outbreak sickened 18 people in 13 states with 16 hospitalizations and three deaths.

Listeria Outbreak 2

On April 13, 2022, the FDA announced its investigation of the second mystery Listeria outbreak. The reference number 1057 means 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 has sickened 15 people.

Experienced Listeria Lawyers

If you developed a Listeria infection after contaminated food and would like to discuss your legal options, please contact our Listeria lawyers. Our Food Safety Team has more experience handling Listeria lawsuits than any other law firm in the country securing some of the largest Listeria settlements in U.S. history including a recent award of $6.4 million.

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.