CDC Links Listeria Outbreak to Hispanic-Style Cheeses

Although the CDC has not yet identified a specific type or brand of cheese making people sick, it is advising consumers not to eat any Hispanic-style fresh and soft cheeses including queso blanco, queso panela and queso fresco.

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

Analysis of samples collected from people who were sick found the bacteria to be closely genetically related, indicating the individuals likely got sick from the same food. Now, state officials are testing samples of cheese from stores where sick people reported shopping in hopes of finding which specific cheese is contaminated.

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.

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.

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.