Listeriosis is an infection that occurs mainly in humans after consuming food contaminated by the Listeria bacteria, especially by the variant monocytogenes . According to the European Food Safety Authority (EFSA), in 2017 there were 2,480 cases of listeriosis in humans in the European Union, with 227 deaths in 16 member states, which implies a mortality rate of 13.8% . In Spain, in that same year, 284 cases were confirmed.
The foods that are most associated with listeriosis are refrigerated ready-to-eat foods with a long shelf life. In the outbreaks of listeriosis that have occurred worldwide, the causes have been ready-to-eat meat products such as cooked sausages or patés, smoked fish , dairy products such as soft cheese, raw milk and ice cream made with it, ready-made salads, as well as vegetables and fresh fruit.
A presence of the bacteria in food above 100 cfu / g can be dangerous, something that is rare. However, as the bacteria are highly survivable and multiply very rapidly, even a low proportion of samples that exceeds this level can be a health concern.
How is food contaminated?
As we have mentioned, the foods that are most associated with listeriosis are the refrigerated ready-to-eat foods. Well, the contamination of these usually occurs before the final packaging or in the subsequent handling process during its commercialization, that is, when it is sliced . It can also be produced at home. If the manufacturing process of these foods does not include a treatment that eliminates Listeria , such as cooking or baking, whether it is contaminated or not will depend on the measures taken throughout the entire food chain, with special emphasis on maintenance of the cold chain .
As a result of the food alert issued by the Spanish Agency for Food Safety and Nutrition (AESAN) due to the presence of Listeria monocytogenes in several batches of meat products produced by EMBOTITS D’OIX SL : Botifarra d’ou, Bull blanc, Botifarra negra, Botifarra de fetge and Botifarra all julivert and although, as of today April 30, 2021, no case of listeriosis associated with this alert has been confirmed in our country, we will tell you what are the typical symptoms of a Listeria infection. Take note!
Symptoms of listeriosis
The symptoms of listeriosis are very similar to those of the flu : muscle aches, fever, nausea, and diarrhea. However, there are people to whom this infection goes unnoticed. Others may spread to the nervous system causing headache, confusion, stiff neck, tremors and seizures, and loss of balance.
People who are most at risk of contracting an infection have the worst prognosis in case of listeriosis. We are referring to children, over 65 years of age, pregnant women, people with AIDS, cirrhosis, diabetes or those who have had their spleen removed or are undergoing chemotherapy treatment . In pregnant women it can cause abortions or pre-term deliveries.
If the infection reaches the brain, the consequences can be serious. Cranial nerve palsy, encephalitis (inflammation of the brain), meningitis (inflammation of the meninges), meningoencephalitis (a combination of meningitis and encephalitis), and brain abscess can occur.
Prevention of listeriosis at home
It is important to respect what the labels of what we buy indicate : the expiration date, the way of conservation and the way of consumption (if it indicates that it should not be consumed raw, do not do it). In this way we will prevent the bacteria from multiplying until it becomes dangerous if it were present in the food in question.
When it comes to cooking, it is advisable to fully cook the food , that is, it reaches 70 degrees Celsius for two minutes. Food that needs to be in the freezer should be kept at temperatures below 5 degrees Celsius.
It goes without saying that both the kitchen utensils, pots, pans, tables and others as well as the refrigerator must be clean. Also our hands before and during the cooking process. We must separate raw foods from those that are cooked and keep them at a suitable temperature.
Risk groups should take extra precautions such as avoiding non-pasteurized dairy products, ready-to-eat meat products such as cooked ham or refrigerated pâté, as well as smoked fish.
