Physicians should be prepared to field calls from concerned parents who believe their children may have consumed a product potentially contaminated with Listeria. In general, someone who has eaten a recalled food product but has no symptoms doesn’t need a laboratory evaluation or treatment. Screening blood cultures is not indicated, and routine tests such as a complete blood count are unlikely to be helpful. Instead, patients should be counseled about the symptoms of listeriosis and undergo prompt evaluation if any develop within 2 months of exposure. The typical interval between exposure and the development of symptoms is 1 day to 3 weeks, but may be as long as 70 days.
Although Listeria infection may result in gastrointestinal symptoms, stool cultures are not recommended for diagnosis. According to the CDC, ingestion of food contaminated with Listeria occurs frequently because the organisms are commonly found in the environment. Although uncommon, intermittent fecal carriage and shedding have been observed in asymptomatic individuals.
Back at the grocery, I sighed and resigned myself to a grilled cheese sandwich for dinner. I turned and saw another woman in the aisle stop and read the sign on the freezer case.
“It’s a little scary,” she said with a sigh. “It seems like there is another recall every week, and I’m wondering what’s safe to eat.”
The parents of our patients may have similar questions. Although the Food and Drug Administration offers detailed guidance for food manufacturers about reducing Listeria contamination, perfect compliance wouldn’t eliminate the risk for consumers because L. monocytogenes is widespread in the environment. The organisms are found in water, soil, sewage, and decaying vegetation, and can be isolated from a variety of animals. Fresh fruits and vegetables are “healthy” choices as long as they are handled and prepared appropriately. Conversely, unpasteurized milk and milk products can never be considered safe.
That’s food for thought.
Dr. Bryant is a pediatrician specializing in infectious diseases at the University of Louisville (Ky.) and Kosair Children’s Hospital, also in Louisville. She had no relevant financial disclosures.