Should we be concerned about infections associated with the consumption of contaminated pizzas in France?

Elena Gonzalez Fandos, University of La Rioja

March 18 France notified a health alert on frozen pizzas contaminated with the bacteria Escherichia coli Shiga toxin (known as STEC) producer. The pizzas involved in the alert have been distributed in other countries (Luxembourg, Belgium, among others) but not in Spain.

During the month of March, the French authorities carried out various press releases regarding ongoing investigations into severe cases of hemolytic uremic syndrome in children.

As of March 30, the French authorities communicated who are following up 75 cases in children, 41 of them with hemolytic uremic syndrome aged between 1 and 18 years, with a mean age of 7 years. Till the date two deaths have been recorded in children.

Epidemiological, microbiological and traceability investigations carried out by the French authorities have confirmed a possible link between the appearance of clustered cases of hemolytic uremic syndrome and the consumption of frozen pizzas from the Fraîch’Up range of the Buitoni brand contaminated by bacteria E. coli Shiga toxin producers (STEC 026).

Last March 18 market withdrawal started of the pizzas of the aforementioned range, marketed since June 2021. In addition, the authorities have asked people who have said pizzas not to consume them and destroy them.

What is the danger of bacteria E. coli?

Escherichia coli is a bacterium that is naturally present in the intestines of people and warm-blooded animals. Most strains of E. coli they are not pathogenic. However, on some occasions this bacterium has been involved in intestinal infections and extraintestinal infections.

Six categories of E. coli that produce diarrhoea: enterotoxigenic (ETEC), enteropathogenic (EPEC), enteroinvasive (EIEC), enteroaggregative (EAEC), diffuse adhesion (DAEC) and Shiga toxin producers (STEC). The latter is also known as E. coli verotoxigenic (VTEC), since they produce cytotoxins (Vtx) that affect cells of the Vero line.

Specifically, STEC can cause serious illness in people. In the European Union in 2020, infection by this bacterium was the fourth most frequent foodborne disease in people, with 4,446 people affected (cases), 652 hospitalizations, and 13 deaths.

It should be noted that one of the largest outbreaks associated with this bacterium it occurred in Germany in 2011 with 3128 cases, 817 with hemolytic uremic syndrome and 46 deaths. In said outbreak, the foods involved were sprouted seed sprouts.

Food is the main cause of transmission

Transmission of STEC occurs primarily through the consumption of contaminated food and water. Although transmission can also occur from person to person by fecal-oral transmission due to poor hygiene measures. Sometimes it can be caused by direct contact with infected animals or their feces.

Most outbreaks of E. coli Shiga toxin producer have been associated with the consumption of undercooked meat, especially hamburgers and minced meat; raw milk; dairy products made from raw milk; uncooked vegetables (lettuce, spinach, sprouts, among others) and fruits.

Therefore, it is important to avoid food contamination with STEC by maximizing hygiene measures during the production, handling and consumption of food. Food business operators are responsible for placing safe food on the market. To do this, they must comply with hygiene standards and implement self-control systems. It should be noted that this bacteria are destroyed by heat so proper cooking is an effective tool.

Should this type of infection alert us?

infection by E. coli Shiga toxin-producing disease initially manifests as severe abdominal pain, watery diarrhea, and sometimes vomiting, followed by bloody diarrhea and hemorrhagic colitis (a type of gastroenteritis). The incubation period ranges from 2 to 10 days.

In general, affected people usually recover within about ten days, but in some cases, especially in children and the elderly, the infection can evolve and trigger a serious illness: hemolytic uremic syndrome (HUS).

Children affected by this syndrome present paleness, fatigue, decreased urine volume and in some cases seizures. This syndrome can lead to kidney failure and trigger death. It is estimated that between 5 and 10% of infected children progress to hemolytic uremic syndrome.

In 2020 in the European Union the hemolytic uremic syndrome presented in 320 cases of the 4,446 notified, being more frequent in children from 0 to 4 years old (234 cases), followed by children from 5 to 14 years old (57 cases).

How to prevent transmission

To prevent transmission of E. coli producer of Shiga toxins, it is important to adopt the following measures in the preparation and consumption of food, especially in children under 15 years of age and the elderly:

Hygiene measures must be followed during the handling and cooking of food. Handwashing after going to the bathroom, before preparing food and before consumption is essential.
Raw foods should be kept separate from cooked foods.
Cross-contamination between raw and cooked foods should be avoided. For this, it is essential to wash hands before and after handling raw food and to wash surfaces and utensils in contact with raw food (boards, knives, etc.).
You have to cook the meat properly, especially if it is minced meat or hamburgers. A temperature of 70ºC must be reached in the center for at least 2 minutes.
Raw milk should not be consumed.
In children under five years of age, the consumption of cheese and other dairy products made with raw milk should be avoided.
Vegetables and fruits, especially if they are to be eaten raw, should be carefully washed and, if possible, peeled before preparation and consumption. The washing can reduce microbial contamination, but its effect is limited.
Flour-based preparations (pizza, cookie dough, cakes, etc.) should not be eaten raw or undercooked.
In the preparation of packaged foods, the indications reflected on the container must be followed, especially in relation to the temperature and cooking time indicated by the manufacturer.
Cooked foods that are not going to be consumed immediately should be kept refrigerated. Before consumption, they must be reheated in a convenient way.
If cooking or reheating is done in the microwave, special attention must be paid to the times, since longer processes may be necessary.