The FDA, along with the CDC and state and local partners, is investigating a multistate outbreak of Listeria monocytogenes infections potentially linked to Dole packaged leafy greens. A recall has been initiated, but there is concern consumers may have unused portions in their homes.

A full list of recalled products is available on FDA’s website. In addition to Dole Fresh Vegetables Inc. brand products the recall includes salads packaged for Walmart, Kroger, and Lidl brands, among others.

According to the Centers for Disease Control and Prevention, as of Dec. 22, there are 16 people infected with the outbreak strain of Listeria monocytogenes reported from 13 states. Illnesses started on dates ranging from August 16, 2014, to Oct. 17, 2021. One case occurred in 2014 and the remaining cases occurred between 2018 and 2021. Of 14 people with information available, 12 have been hospitalized.

Two deaths have been reported from Michigan and Wisconsin. Whole genome sequencing showed that bacteria from sick people’s samples are closely related genetically. This suggests that people in this outbreak got sick from the same food.

In response to sample analyses and the ongoing outbreak investigation, Dole has agreed to voluntarily suspend operations at its Bessemer City, NC, facility and Yuma, AZ, facility and has voluntarily recalled all products and brands from those facilities. Those products have production lot codes beginning with either the letter “N” or “Y” in the upper right-hand corner of the package and Best if Used By dates from Nov. 30, 2021, to Jan. 8, 2022.

“A common question is why did it take so long to link all the illnesses?,” said food safety attorney Bill Marler.

“It is likely that there has been low-level, but persistent Listeria contamination in both processing facilities that was not being picked up in the first epidemiological investigations.  It is most likely that the outbreaks were noticed, and the illnesses linked – both past and present – when product samples from various states were uploaded to CDC’s PulseNet.”

The CDC investigated this outbreak in 2019 and 2020 but was unable to gather enough data to identify the source in the past. CDC reopened the investigation in November 2021 when four new illnesses were reported since the end of August.

In October 2021, as a part of routine retail sampling, the Georgia Department of Agriculture collected a product sample of prepackaged salad mix from a grocery store for testing. According to the U.S. Food and Drug Administration the sample tested positive for Listeria monocytogenes.

In response to the sample results, Dole initiated a recall of packaged garden salads in October 2021. These products are now past their “Best if Used By” dates. The positive sample was later sent for whole genome sequencing (WGS) analysis; and in December 2021, WGS analysis was completed. The results show that the Listeria monocytogenes in the product sample was a match to the outbreak strain. The FDA is conducting an inspection at the facility that produced the product that tested positive for Listeria monocytogenes.

The FDA is also reporting that the Michigan Department of Agriculture and Rural Development also recently initiated retail sampling of Dole products in their state as part of this investigation. One product containing lettuce from a Dole facility in Yuma, AZ, tested positive for Listeria monocytogenes. Whole genome sequencing analysis showed that the Listeria monocytogenes in the product sample is also a match to the outbreak strain.

The recall related to this outbreak does not include whole head packaged lettuce. A full list of recalled products is available on FDA’s website.

The FDA recommends that anyone who received recalled products use extra vigilance in cleaning and sanitizing any surfaces and containers that may have come in contact with these products to reduce the risk of cross-contamination. Listeria can survive at refrigeration temperatures and can easily spread to other foods and surfaces.

About Listeria infections
Food contaminated with Listeria monocytogenes may not look or smell spoiled but can still cause serious and sometimes life-threatening infections. Anyone who has eaten any recalled products and developed symptoms of Listeria infection should seek medical treatment and tell their doctors about the possible Listeria exposure.

Also, anyone who has eaten any of the recalled products should monitor themselves for symptoms during the coming weeks because it can take up to 70 days after exposure to Listeria for symptoms of listeriosis to develop.

Symptoms of Listeria infection can include vomiting, nausea, persistent fever, muscle aches, severe headache, and neck stiffness. Specific laboratory tests are required to diagnose Listeria infections, which can mimic other illnesses.

Pregnant women, the elderly, young children, and people such as cancer patients who have weakened immune systems are particularly at risk of serious illnesses, life-threatening infections, and other complications. Although infected pregnant women may experience only mild, flu-like symptoms, their infections can lead to premature delivery, infection of the newborn, or even stillbirth.