On Wednesday, the US Department of Agriculture’s Food Safety and Inspection Service announced that more than 21,000 pounds of frozen pizzas are being recalled due to possible listeria contamination.

Listeria in pizza:

According to FSIS, RBR Meat Company Inc.’s Market side supreme frozen pizza may have been “adulterated with Listeria monocytogenes,” prompting the company to recall it.

The recalled pizza was sold at select Walmart stores in a 50.6-oz. box containing single shrink-wrapped 16-inch pizzas labeled as “Marketside Extra Large Supreme Pizza,” with lot code 20547.

FSIS discovered the Listeria monocytogenes bacteria during routine sampling. The recall announcement stated “There are no confirmed reports of adverse reactions from consumption of the pizzas at this time.”

This recall is a Class I recall, which, according to the USDA, means that it’s a health hazard situation where there is a reasonable probability that the use of the product will cause serious, adverse health consequences or death.”

Consumers who have bought the product shouldn’t eat it, but are advised by FSIS to either throw it away or return them to the place of purchase.

Walmart distribution centers in California, Nevada, Utah and Washington all had the pizzas shipped to.

Symptoms of the illness:

Listeriosis is a serious infection, it can be particularly dangerous for pregnant women and older people, and it’s caused by eating contaminated food. According to the US Centers for Disease Control and Prevention, its symptoms include fever, muscle aches and sometimes diarrhea or other gastrointestinal problems.

According to the CDC, around 1,600 cases are reported in the United States every year, with 260 resulting in death.

Federal health officials announced last week an unrelated recall of soft raw milk cheese made by Vulto Creamery due to a listeria outbreak which caused six cases of illness including two deaths.

Sargento Foods recalled of several cheeses due to potential listeria contamination last month and forced the company to cut ties with one of its suppliers.