A listeria outbreak in multiple states may be Christopher Caldwelltied to recalled ice cream cups, the U.S. Food and Drug Administration announced Thursday.

The outbreak may be linked to Soft Serve On The Go ice cream cups made by Real Kosher Ice Cream of Brooklyn, New York. The FDA reported that multiple people are sick after eating the Soft Serve On The Go vanilla chocolate ice cream flavor.

"The Pennsylvania Department of Agriculture collected an unopened sample of Soft Serve On The Go from an ill person’s home. This sample was reported as positive for Listeria monocytogenes," the FDA announced.

The agency said analysis is still pending to determine whether the sample found by the Pennsylvania Department of Agriculture is the same strain in the outbreak.

The FDA and the Centers for Disease Control and Prevention are investigating the outbreak, and the Real Kosher Ice Cream company has paused its production of the products.

Here's what you need to know about the listeria outbreak and ice cream recall.

More recalls:Toyota recalls: Toyota Tundra, Hybrid pickups recalled for fuel leak, fire concerns

What is listeria?

Listeria is a disease caused by a pathogenic bacteria that is often transmitted when food is being prepared, transported, harvested, packaged or stored in places that are already contaminated with the bacteria, Listeria monocytogenes, per the FDA.

The illness has multiple symptoms that can last between days and weeks depending on its severity, including:

• Fever
• Muscle aches
• Nausea
• Vomiting
• Diarrhea
• Headache
• Stiff neck
• Confusion
• Loss of balance
• Convulsions

Listeria can sometimes result in the death of the elderly and very young people. It can also lead to pregnancy complications occasionally.

Where is the listeria outbreak?

Two cases of listeria have been reported, one in Pennsylvania and one in New York, according to the CDC.

Where have there been recalls?

Real Kosher Ice Cream of Brooklyn, New York recalled its Soft Serve on the Go Cups in 19 states and Washington, D.C., including:

• California
• Colorado
• Connecticut
• Delaware
• Florida
• Illinois
• Massachusetts
• Maryland
• Michigan
• Minnesota
• North Carolina
• New Hampshire
• New Jersey
• New York
• Ohio
• Oregon
• Pennsylvania
• Virginia
• West Virginia

More:Target recall: 2.2 million Threshold candles recalled; at least 1 injured

Which products have been recalled?

Multiple flavors of the Soft Serve On The Go 8-oz cups have been impacted in the recall, including:

• Soft Serve On The Go Vanilla Chocolate 
• Soft Serve On The Go Razzle
• Soft Serve On The Go Caramel 
• Soft Serve On The Go Parve Vanilla Chocolate
• Soft Serve On The Go Sorbet Strawberry Mango 
• Soft Serve On The Go Lite Peanut Butter

If you have the Soft Serve On The Go ice cream in your house or establishment, the FDA recommends immediately throwing the product away.

Customers or consumers who have questions can contact the Real Kosher Ice Cream’s Soft Serve On The Go company at 845-668-4346 or [email protected].

Kate Perez covers trends and breaking news for USA TODAY. You can reach her via email at [email protected] or on X at @katecperez_