When do symptoms of Listeria infection typically occur?

Symptoms of Listeria infection typically occur within a range of 3 to 70 days after ingestion of contaminated food. This long incubation period is one of the distinctive characteristics of Listeria monocytogenes, the bacteria responsible for listeriosis. After consuming contaminated food, the bacteria can remain in the body for several days or even weeks before leading to symptoms, which can include fever, muscle aches, nausea, and diarrhea.

Understanding this incubation period is crucial for food safety and public health, as it can make it challenging to identify the source of the infection. People may not connect their illness to the particular food they consumed, especially since the symptoms can take a long time to manifest. Those most at risk include pregnant women, newborns, older adults, and individuals with weakened immune systems, which makes awareness about this bacteria and its effects particularly important for food handlers and managers.