Health authorities interviewed five of the seven people who were infected. Four reported eating queso fresco, including one person who had consumed El Abuelito’s product and another who had eaten Rio Grande’s, before falling ill and being hospitalized.

However, there is not enough evidence to determine if the specific multistate outbreak is linked to El Abuelito queso fresco. Further analysis is needed to determine if the discovered listeria matches the strain identified in the outbreak. Hispanic-style fresh and soft cheese is the Centers for Disease Control and Prevention’s leading hypothesis for the cause of the illness.

Meanwhile, the CDC is advising consumers to throw away the recalled cheese or return it to where it was purchased. Refrigerators, containers and surfaces that may have come into contact with the cheese should also be cleaned.

The CDC advises consumers to buy cheeses made with milk that has been pasteurized, a process that kills listeria and other germs. Products can still become contaminated if a facility has unsanitary conditions, the agency said.

The number of people sickened from this outbreak is likely higher than the seven recorded because some individuals recover without medical care and are not tested for infection, the CDC said.

El Abuelito has stopped producing and distributing the products while the investigation into the cause of the problem continues. Customers with questions may contact El Abuelito directly, Monday to Friday from 8 a.m. to 5 p.m. ET and Saturday from 8 a.m. to 12 p.m. ET, at 973-345-3503.

Symptoms of a listeria infection

Listeriosis, the infection caused by eating food contaminated with the bacterium Listeria monocytogenes, most often causes sickness in adults 65 and older, people with weakened immune systems, pregnant women and newborns. Symptoms may include headache, stiff neck, confusion, loss of balance, fever, muscle aches and convulsions. Pregnant women typically experience only fever, fatigue and muscle aches, but a listeria infection during pregnancy can lead to miscarriage, stillbirth, premature delivery or life-threatening infection of the newborn.

People usually report symptoms one to four weeks after eating food contaminated with listeria. But some people have reported symptoms from as early as the day of exposure to as late as 70 days after.

Listeriosis is diagnosed when a bacterial culture grows the germ from a sample of body tissue or fluid, such as blood, spinal fluid or the placenta. It is treated with antibiotics.

About 1,600 people in the U.S. get listeriosis each year, resulting in about 260 deaths, the CDC estimates. Americans 65 and over are four times as likely as others to get a listeria infection.

Editor’s note: This article, originally published Feb. 15, 2021, has been updated with information on the El Abuelito recall.

Aaron Kassraie writes about issues important to military veterans and their families for AARP. He also serves as a general assignment reporter. Kassraie previously covered U.S. foreign policy as a correspondent for the Kuwait News Agency’s Washington bureau and worked in news gathering for USA Today and Al Jazeera English.