Ice cream products from Big Olaf Creamery in Sarasota, Florida, are likely responsible for a multistate listeria outbreak, according to an investigation from the Centers for Disease Control and Prevention.
One person has died and 22 others have been hospitalized since the outbreak started in January 2021, according to the CDC. A dozen of the cases were reported in Florida, and eight others were among people who had traveled to Florida in the month before they got sick.
Listeria monocytogenes, a bacteria that infects people via contaminated food, is rare but can cause serious infections. Nearly 95% of people with listeriosis — the disease the bacteria causes— require hospitalization, according to the CDC. The disease’s fatality rate is around 20%.
The bacteria poses the biggest threat to pregnant people, newborns, adults 65 years or older and people with weakened immune systems.
“When we have a listeria outbreak, we have a very high concern because the ramifications are so serious. While we don’t have a lot of cases, the ones we do have tend to be serious,” said Keith Schneider, a food safety professor at the University of Florida.
At least 14 people in the recent outbreak said they ate ice cream in the month before their illness started, the CDC said. Six said they ate Big Olaf Creamery ice cream or consumed ice cream from locations that may have carried the brand.
Big Olaf products are only sold in Florida. The company began telling stores not to sell its ice cream on Friday, the CDC said. Although Big Olaf did not respond to NBC News' requests for comment, it said in a statement to the Associated Press that the link between its ice cream and the listeria outbreak is not confirmed.
The company added that it is cooperating with state and federal health officials.
“We have been transparent and have answered all their questions and provided them with all the information requested from us, as the health and well being of the public is our first priority,” the statement said.
On Tuesday, the estate of Illinois resident Mary Billman filed a lawsuit against Big Olaf, alleging that contaminated ice cream was responsible for her death in January.
How listeria gets into food
The CDC recommends that people throw away Big Olaf products and contact their health care provider if they develop symptoms such as diarrhea accompanied by fever.
Schneider said listeria can survive for extended periods of time in cold, damp spaces.
In 2015, the CDC linked a multistate listeria outbreak to Blue Bell Creameries products. Ten people were hospitalized and three of them died. In 2020, a federal court in Texas ordered Blue Bell to pay $17.25 million in criminal penalties.
Other listeria outbreaks have been linked to packaged salads, cantaloupes and frozen vegetables. Schneider said most listeria outbreaks occur when bacteria from soil, water or vegetation is introduced into a food processing or manufacturing facility.
“It could come on somebody’s shoe walking in from the parking lot,” he said. “So it’s one of those things where almost anybody or any business can be susceptible.”
In the Blue Bell outbreak, he said, contaminated liquid from condensation dripped onto the processing line.
“Typically, where we see listeria becoming a problem is when sanitation breaks down or it gets established in a floor drain or on a piece of equipment, and that piece of equipment isn’t sanitized to a high enough standard and then it ends up contaminating a food product,” he said.
The CDC recommends that businesses clean and disinfect any areas or equipment that may have touched Big Olaf ice cream. Consumers should also clean areas, containers or utensils that touched the products.
“What’s protecting the listeria is the moisture content of that ice cream, the fat content of that ice cream. Once it gets outside of that, it’s not going to survive for extended periods of time,” Schneider said. “But out of an abundance of caution, you might want to wipe everything down.”
Listeriosis symptoms can be wide-ranging
Listeriosis affects about 1,600 people in the U.S. each year, far less than the most common food-borne illnesses. (The country records 1.35 million annual salmonella infections, by comparison.)
“Despite the fact it’s not very common, it’s the one that we worry about the most when talking about processed foods,” Schneider said.
People with listeriosis may develop muscle aches, nausea, vomiting, joint pain, headache, stiff neck, confusion, loss of balance and convulsions.
Among pregnant people who get infected, fever is the most common symptom, but vomiting and diarrhea are rare. Listeriosis can cause dangerous pregnancy-related complications such as miscarriages, stillbirths or premature births. Newborns whose mothers were infected may develop life-threatening blood infections, pneumonia or meningitis.
In some listeriosis cases, people get sick within 24 to 72 hours, Schneider said. But if the bacteria spreads to parts of the body beyond the gut, it may take several weeks for symptoms to develop.
“If you have an invasive form, Listeria has the ability to actually hide out in white blood cells. It’s kind of insidious," Schneider said.
He added that the severity of an infection isn't necessarily correlated with the amount of contaminated food someone ate.
“If I have a very susceptible individual, it may take a very small amount," he said.