Processed meats, such as polony and sausages are believed to be the main cause of the illness. Listeria multiplies in uncooked food kept in the fridge.  This is why processed meats, smoked meats and soft cheeses that are not cooked are often linked to outbreaks.


Listeriosis affects people with weak immune systems, pregnant women, elderly and babies in the womb who contract it from their mothers during birth. The National Institute for Communicable Diseases (NICD) says that the vast majority of people who consume these products will in fact be fine.

A person with listeriosis usually has fever and muscle aches, often preceded by diarrhea or other gastrointestinal symptoms. Almost everyone who is diagnosed with listeriosis has invasive infection. This means that the bacteria are spread from their intestines to their blood stream or other body sites. The disease may occur as much as two months after eating contaminated food.

Crews are advised to check ready-to-eat meat products. NICD also recommends to use diluted bleach to clean areas where the meat products may have been kept. Local ship chandlers should be able to provide clear laboratory tests for other cold meats that are sourced locally.

Moreover, very important for the prevention of the disease is the safe handling, cooking and consumption of food. This includes washing raw vegetables and cooking raw food thoroughly, as well as reheating leftover or ready-to-eat foods until steaming hot.

Below you can find an infographic, informing about safe ways to consume food

Credit: WHO