We hear about it often in the last period, given the increased clinical cases recorded in various regions. Food listeriosis, caused by the contamination of foods by the bacterium Listeria monocytogenes, has recently received particular attention from the media point of view after the presence of the Listeria ST 155 strain was detected in some frankfurters based on poultry.
There were three victims and several hospitalized people following the consumption of this food without having cooked it first (indication on the label).
Listeria is a bacterium that can also be present in other foods and has been known for some time, precisely for its ability to survive and proliferate even at refrigeration temperatures and in conditions that are adverse for other bacteria. In the vast majority of cases, consuming contaminated food does not present symptoms or may show mild ones at the gastrointestinal level. However, it is essential to consider some aspects to understand who is most at risk and the preventive actions that can be implemented.
Let’s see more details in this article.
Listeria Bacterium: What It Is And In Which Foods It Is Found
As anticipated, the bacterium Listeria monocytogenes, responsible for listeriosis, is highly versatile and can survive and proliferate even in adverse conditions for other bacteria. It can withstand high and low temperatures and dry very well. Specifically, it multiplies between +45°C and -1.5°C in foods stored at refrigeration temperature (4°C). On the contrary, it is susceptible to the traditional home cooking temperatures of food, a fundamental element for preventing risks.
But What Are The Foods Most Subject To The Risk Of Food Listeriosis?
Being a ubiquitous bacterium, which can be present in the soil, water, and vegetation, Listeria monocytogenes can contaminate foods such as:
- cold smoked salmon;
- raw meat;
- fresh vegetables;
- soft cheeses (incredibly moldy);
- slightly seasoned sausages.
Healthy children and adults may be infected but rarely develop severe disease. On the other hand, other subjects may be more exposed to more severe consequences. Let’s see the categories most at risk.
Food Listeriosis: Subjects At Risk
Although there are also cases of disease due to contact with infected animals – especially cattle, sheep, and pigs – in the occupationally exposed categories, the infection is transmitted to humans mainly via food. Among the most at-risk categories are undoubtedly pregnant women, who generally experience flu-like syndrome (fever, fatigue, pain).
In some cases, however, the consequences can also affect the fetus, leading to early deliveries or neonatal infections, even up to abortion (especially in the early stages of pregnancy). Others at risk are the elderly and individuals with immune system deficiencies or chronic diseases. In these cases, the incubation period is highly variable, ranging from 3 to 70 days. The most severe consequences can lead to bacteremia involving the central nervous system: meningitis, meningoencephalitis, rhombencephalitis, and brain abscesses.
Food Listeriosis: Prevention Tips
Ways of storing, preparing, and consuming food are three elements to which it is essential to pay attention to avoid the risk of contamination. So, first of all, it is essential to follow what is indicated on the food package’s label. In fact, with labeling, food business operators must provide all the information necessary to allow consumers to use food safely. Another important aspect is related to hygiene and food handling. Correct and conscious actions – both in the private sphere and among those who handle and prepare food in their business (e.g., restaurateurs, chefs, etc.) – can substantially reduce the risk of food listeriosis.
Some prevention tips:
- wash your hands often;
- frequently clean surfaces and materials in contact with food (utensils, small appliances, refrigerators, tea towels, and sponges);
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