Buitoni pizza scandal, botulism in a restaurant in Bordeaux, collective food poisoning after a Christmas meal: food poisoning regularly makes the headlines and affects many people each year in France. According to a report from Public Health France, collective food poisoning infections (TIAC) have never been so numerous since 1987 and the establishment of surveillance. In 2022, 16,763 people were affected and 17 died. However, simple actions, particularly when it comes to defrosting, can prevent the risk of poisoning and prepare food safely…
Why shouldn't you defrost meat at room temperature?
Do you defrost your chicken at room temperature overnight before cooking it the next morning? Attention : leaving the meat in the open air encourages the multiplication of bacteria and increases the risk of food poisoning. “ Freezing stops the growth of bacteria but as soon as they are at room temperature again, they resume their growth very quicklyconfirms Dr. Océane Sorel, virologist and author of the work Viruses, bacteria, microbes: everything you need to know to escape them and the Instagram account @thefrenchvirologist.. Cooking is not always uniform and sufficient to kill the microbes that have proliferated. In addition, some spores and toxins are not necessarily destroyed by cooking. » All the more reason to play the caution card!
Defrosting: what are the risks?
Salmonella, Escherichia coli (or E. coli), Campylobacter or Listeria : many pathogenic germs are just waiting for one thing… to come out of the freezer to multiply! And the consequences can be serious for the most sensitive populations such as young children (especially if they are under five years old), pregnant women, the elderly or immunocompromised people. “If defrosting is not carried out properly, bacteria will resume their growth. », underlines the virologist.
The E. Coli bacteria
Escherichia coli often makes headlines. In 2011, the bacteria was the cause of an epidemic of hemolytic and uremic syndromes (HUS) which caused more than fifty deaths in Germany. In question ? Sprouted seeds. In 2022, these are frozen pizzas from the Buitoni brand which caused several dozen cases of serious infections in children and adolescents, two of whom have unfortunately died.
Ground beef is a common source of E. coli, because it is a hyper-manipulated meat that comes into contact with many different machines and people (grinders, operators, etc.) that are potentially contaminating. Additionally, chopping spreads the bacteria to the heart of the meat (so if the steak is undercooked, then the bacteria in the center will not be killed by cooking and may make consumers sick). Dr. Océane Sorel, virologist
” It's important to cook ground steaks thoroughly, even frozen steaks, and avoid rare minced steaks for little ones or other fragile people! »
Lbacterial infection E. coli manifests itself by symptoms which vary from one person to another: from simple diarrhea to vomiting, including intestinal cramps and hemorrhagic diarrhea. “ Young children and the elderly or immunocompromised people are particularly at risk of developing serious forms, because their immune system is not always capable of controlling the bacteria. A very serious complication, hemolytic-uremic syndrome, can lead to kidney failure or even death. »
Salmonella
Salmonellosis remains the second leading cause of gastrointestinal infection in humans after campylobactériose. Infections by Salmonella most often manifest as symptoms of gastroenteritis: fever, diarrhea, vomiting and abdominal pain. In pregnant womensalmonellosis can lead to premature birth or bacterial infection of the baby and death in utero.
« The best protection against the risk of salmonellosis is proper cooking of food, especially meats, at least 65°C for 5 to 6 minutesrecalls the Pasteur Institute. For frozen or frozen minced steak, cooking must be carried out without prior defrosting as it increases the risk of bacterial multiplication. Cold blocks the development of bacteria but does not kill them. »
Listeria
The bacteria Listeria monocytogenes is also causing food poisoning. « Raw foods are the most frequently contaminated: poorly washed fruits and vegetables, unpasteurized dairy products and raw milk cheeses, undercooked meats, cold meats, smoked and raw fish, raw shellfish, and even sprouted seeds.specifies the website of the Ministry of Agriculture. It is impossible to recognize food contaminated with Listeria; it has the same appearance, taste and smell as a healthy product. The bacteria is resistant to cold and can therefore proliferate in the refrigerator and survive in the freezer. On the other hand, it is killed by heat ».
Symptoms of listeriosis can appear two days to two months after eating contaminated food and are characterized by fever, diarrhea and vomiting. “ In addition to the non-invasive form which occurs quickly after ingestion of contaminated food, the invasive form is much more severe.confides Dr. Sorel. It occurs when the bacteria crosses the wall of the intestines and spreads to the rest of the body, with an incubation phase that can be long and a mortality rate of around 20 to 30%. The invasive form can cause fever and other symptoms associated with meningitis or septicemia. »
How to defrost meat faster? Why is hot water (really!) not a good idea?
The three safest methods of defrosting meat (or any other food) are:
- in the refrigerator;
- in the microwave in defrost mode;
- directly in the oven: for example, to defrost frozen bread.
Freezing does not kill bacteria, insists the virologist. She only “puts them to sleep”! Dr. Océane Sorel (@thefrenchvirologist)
At the slightest opportunity, when the temperature is ideal for them – even more so when, for example, you run your frozen turkey escalope under hot water! – they will resume their little bacterial life and multiply. Worse: the freezing step makes their job easier. In fact, when the food froze, thousands of ice crystals formed inside it, which slightly damaged its structure. When it thaws, the bacteria will take advantage of this destructuring to easily access the food they need. Defrosting serves them nutrients on a silver platter. »
Can you defrost, cook and refreeze?
He is very strongly advised against refreezing a product that has already been thawed. « Unless the food has been properly thawed before cooking – that is, not at room temperature, but in the refrigerator – and then cooked at a high temperature for long enough, which kills microbes, specifies the specialist in her work. For example, you can defrost a frozen turkey raw, cook it to make a blanquette, then freeze the leftover blanquette. »
Fridge versus microwave: what is the best way to quickly defrost chicken?
If you want to quickly defrost meat, especially chicken, opt instead for the microwave in defrost mode before cooking it in your traditional oven. Otherwise, you can let it defrost in the fridge overnight and cook it the next morning. « Be careful, the microwave does not necessarily allow you to obtain a uniform temperature in the food and therefore to “kill” all the bacteria with heat as well as cooking in a pan or in the oven. », recalls Dr Sorel.
How to defrost ground steak?
Ground beef being a common source of bacteria E. coli, it is advisable to cook the ground steaks directly while they are still frozen or deep-frozen. No rare meat for the youngest and fragile people!
Freezing and defrosting: good practices
When it comes to freezing and defrosting, simple hygiene measures help avoid inconveniences:
- GOOD respect the cold chain by taking an insulated bag with you to transport your frozen foods before quickly putting them in the freezer when you get home;
- freeze fresh food before its use-by date (DLC). « The closer you are to the expiry date, the more you increase the risk of food poisoning when defrosting. », confirms Dr Sorel.
- clean your freezer at least once a year ;
- pack food in airtight bags or in suitable containers before putting them in the freezer;
- do not overload the freezer so that air can circulate well between the foods.
