Listeriosis fact sheet

Cause

Consuming food contaminated with Listeria monocytogenes bacteria causes a condition called listeriosis. The bacteria can occur in soil, water or plant material and contaminate food products during any stage of the food production and processing cycle between farms and factories.

Listeriosis symptoms

Symptoms can occur within two days of consuming contaminated food. Some patients have however presented with symptoms more than a month after consuming contaminated food, which makes the source of the infection difficult to trace. Symptoms include:

• Fever
• Headache
• Muscle aches
• Nausea
• Vomiting that is sometimes preceded by diarrhoea
• Stiff neck
• Disorientation
• General weakness
• Convulsions

If you experience these symptoms, consult your doctor immediately.

Diagnosis and treatment

If your doctor suspects that you have contracted listeriosis, you will be hospitalised immediately. Samples of your blood and/or stool will be sent for laboratory tests to confirm the diagnosis, after which your doctor will prescribe a course of antibiotics. You may also receive an IV drip to expedite the treatment. Most patients recover within seven days after starting treatment.

High-risk individuals

Some people are at a higher risk of contracting listeriosis, such as:

• People with compromised immune systems;
• Older adults;
• Infants; and
• Pregnant women

Prevention

The Listeria Monocytogenes bacteria are resilient as they can tolerate salty environments and temperatures as low as -25 degrees Celsius, which means that even frozen food can be contaminated. It is therefore wise to follow these preventive measures when handling food:

• Wash your hands thoroughly with soap and warm water before you handle food.
• Separate raw food from cooked food, as the listeria bacteria are extremely heat sensitive.
• Cook foods thoroughly – don’t prepare half-cooked meals and steer clear of uncooked food products such as deli meats.
• Always store foods under extreme conditions, either frozen or well-heated.
• Use clean water when rinsing fruit and vegetables.
• Use warm water and antibacterial soap to clean all your kitchen surfaces, eating utensils and appliances.