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Listeria: What It Means For You and What Foods Are Most Likely To Contain It

Listeriosis is a food-borne bacterial infection caused by the bacterium Listeria monocytogenes, an important disease because while most healthy people are unaffected by listeriosis, immunosuppressed people (diabetic, HIV positive, etc) and the elderly or newborns are at risk of death from a Listeria infection. Listeriosis may also infect the fetus in pregnant women causing death, miscarriage, or preterm birth. Listeriosis may also occur in animals such as ruminants (sheep, goats, cattle) and, occasionally, other animal species.

How do I get listeriosis?

Most infections are caused by eating contaminated food, but the bacteria can also be spread by inhalation or direct contact. The bacteria Listeria monocytogenes can be primarily found in soil and water, where it may contaminate vegetable produce. Listeria bacteria can survive and thrive in refrigerator temperatures and food with high salt concentrations.

What foods are most likely to contain Listeria bacteria

Listeria can contaminate many food. In fact, back in 2011, the source of the food-borne disease outbreak involving Listeria was traced back to whole cantaloupes from a farm in Colorado. However, the Listeria bacterium is usually found in:

• Unpasteurized milk or milk products such as cheese
• Uncooked meats and vegetables
• Deli meats and hotdogs
• Sprouts

What are the symptoms of listeriosis?

It usually takes anytime between 3 days to 2 months before signs and symptoms show after eating contaminated food. Early signs and symptoms of listeriosis includes fever, muscle pain, nausea, and diarrhea. If the infection has spread to the nervous system, the signs and symptoms may be headache, loss of balance, confusion, stiff neck, and convulsions.

In newborn babies, the signs and symptoms may be difficult to detect. It may include irritability, no or little interest in feeding, fever, and vomiting.

Be sure to watch out for any signs or symptoms of illness if you’ve eaten a food that has been recalled due to a listeria outbreak. Seek a doctor or emergency care immediately if you experience any signs or symptoms listed above.

How do I treat listeriosis?

Listeriosis is treated according to the severity of the signs and symptoms. Due to its deadly nature, it is treated with intravenous antibiotics. Treatment may take up to 4 weeks if the central nervous system is infected. Usually patients are hospitalized to receive treatment.

How to prevent a listeria infection

• FDA recommendations for washing and handling food should be exercised in order to prevent listeriosis.
• Fruits and vegetables, including peeled produce, is to be rinsed thoroughly under running tap water before eating or meal preparation.
• Firm produce such as melons and cucumbers are to be scrubbed with a clean brush.
• Produce are to be dried with a clean cloth or paper towel.
• Uncooked meats, seafood, and poultry must be separated from vegetables, cooked foods, and ready-to-eat foods.
• The kitchen and surrounding environment are to be kept clean and safe.
• Wash hands, knives, cutting boards, and counter tops thoroughly after preparing uncooked food.
• Make sure refrigerator temperatures are correct (freezer < 0ºF, refrigerator < 40ºF).
• Keep fridge clean from any spills and wash it with soap, water, and wiping it down with diluted chlorine bleach and water.
• Poultry and meat has to be cooked thoroughly.
• Storing foods safely and using precooked or ready-to-eat food as soon as possible.
• Avoiding consumption of food that are likely to contain listeria bacteria such as raw milk.
• Throwing out food in your refrigerator that is suspected to have Listeria.