Clean Eating is a Serious Matter

Listeria infection risk higher in pregnant women and older adults

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Food should fuel us and give us energy, not make us sick. But when certain bacteria gets involved, food can cause some serious problems in the body.

A new report shows that pregnant women, older adults and people with weakened immune systems may have a higher risk of contracting a deadly foodborne illness from a bacteria called Listeria.

"Be sure to store foods safely."

The bacteria Listeria monocytogenes can cause a severe infection called listeriosis.

According to the Centers for Disease Control and Prevention (CDC), listeriosis is rare and preventable, but can lead to serious health outcomes like meningitis, miscarriage in pregnant women and death.

Though infections from Listeria are rare, the CDC noted that results of these infections are serious.

Hospitalization for listeriosis is more common than for other foodborne infections. Furthermore, out of the major foodborne pathogens, listeriosis is the third leading cause of death.

​The new report from the CDC, led by Benjamin J. Silk, PhD, utilized data on listeriosis cases reported to US surveillance systems through a variety of networks between 2009 and 2011.

During this time, 1,651 cases of listeriosis were reported. Over half of the infections occurred in adults aged 65 years or older (58 percent) and 14 percent occurred in pregnant women. 

The data also showed that at least 74 percent of infections in people who were under the age of 65 and not pregnant had a condition that compromised their immune system. 

"Almost all listeriosis occurs in persons in higher-risk groups," concluded the CDC.

Listeria infections remain rare, with the average annual incidence found to be 0.29 cases per 100,000 people. However, 21 percent of the cases observed between 2009 and 2011 resulted in death or miscarriage. 

Twelve known outbreaks caused some of these cases, resulting in 224 infections in 38 different states. Five of these outbreaks were found to be related to soft cheeses and two were connected to raw produce. 

These findings led the CDC to conclude that prevention measures should focus on high-risk groups and that extra care should be taken to control Listeria contamination in foods found in previous outbreaks. 

The CDC noted that Listeria is a challenging bacteria to control for a number of reasons, including the fact that symptoms may not develop until weeks after contaminated food is eaten and the germ can survive on refrigerated foods. 

"Listeria can contaminate many foods that we don't usually cook, like deli meats, cheeses and sprouts," reported the CDC. "Some foods we might not suspect can be contaminated with Listeria and cause sickness and outbreaks, such as cantaloupe and celery."

In the face of this challenge, the CDC suggested that people who are at higher risk take extra care and stay informed about which foods have been identified as sources of Listeria.

The public as a whole would be wise to follow the US government's basic food safety steps as the summer cookout season approaches: be sure to clean, separate, cook and chill food properly. 

This report was published in the CDC's Morbidity and Mortality Weekly Report (MMWR) on June 4. No conflicts of interest were reported.

Reviewed by: 
Review Date: 
June 6, 2013
Last Updated:
August 7, 2013