What is Listeria?

Listeria food poisoning symptoms include fever, headache, and tiredness in mild cases, but severe infections can lead to death. Listeria is commonly linked to ready-to-eat foods but occurs in frozen foods as well. Listeria risk is minimized by pasteurization or thoroughly heating food to 165 degrees.

SYMPTOMS

Listeria monocytogenes are bacteria that cause food poisoning. Listeria food poisoning mostly goes unnoticed but can be serious and lead to death in at-risk people, such as the elderly and people with compromised immune systems. If the bacteria are confined to the gut symptoms can be mild such as fever, headache, tiredness, aches and pain or even go unnoticed. If listeria bacteria get outside the gut and into the rest of the body it can cause invasive listeriosis that can lead to severe problems such as meningitis, blood poisoning or even death can occur. Diagnosed listeriosis has the highest mortality rate (20-30%) of any foodborne pathogen.

TRANSMISSION

Listeria bacteria can be killed by pasteurization or cooking food thoroughly above 165 degrees. Listeria food poisoning is falsely thought of to only be associated with items such as deli meats, hot dogs, soft-serve ice cream, fresh fruits, raw vegetables, and unpasteurized dairy products. In reality, Listeria bacteria are able to live in a wide range of conditions and environments. From both acidic and salty conditions, high and low moisture content, and freezing temperatures. This hardiness allows Listeria to survive for long periods in a variety of food products and at processing plants. Because it can thrive in freezing environments, recent studies cited by the FDA have shown that the bacteria are present in a high percentage of frozen raw beef products.

PREVENTION

The CDC has provided guidelines to avoid Listeria food poisoning. General recommendations to avoid food poisoning are:

• cooking raw beef, pork, or poultry thoroughly.
• Ensuring that raw vegetables are thoroughly washed.
• Avoiding Cross-contamination from uncooked meats and ready-to-eat foods.
• Steering clear of unpasteurized dairy products.
• Washing hands, knives, and cutting boards after handling uncooked foods.

Additional recommendations for high risk individuals include staying away from soft cheeses, avoiding deli meats if possible, and thoroughly heating left-over and ready-to-eat foods before eating.

A recent December 2019 recall of White Castle frozen sliders attributed to listeria contamination at the processing plant demonstrates the continued high-risk foodborne illness threat that Listeria monocytogenes presents.