You get home and realise you forgot to leave food to cook. It’s time to defrost something you have in the freezer. But leaving it out in the open to defrost is the worst thing you can do. And it’s not us saying it, it’s science.
It may all seem harmless, but if you leave a steak exposed to room temperature or your bread on the window sill in the sun to defrost, you are putting your health at risk. Although it may not seem like it, changes occur inside these foods (and any other) that can lead to food poisoning. Let’s take a closer look.
Never leave food to defrost outside the refrigerator. It may sound drastic, but it is a practice that should always be avoided. Doing so favors the appearance and proliferation of bacteria that are dangerous to our health. Exposing food to room temperature for hours creates the perfect environment for microorganisms to multiply rapidly. And this translates into a high risk of food poisoning, even if we then cook that food.
The safest way to defrost is in the refrigerator, where the temperature is kept under control. But let’s take a closer look at how the process works.
Benefits of freezing
A process with many benefits. When we freeze food, whatever the type, what we do is transform the water present in the food into ice. It’s a simple explanation but one that makes the idea clear. This process offers numerous benefits and it’s not just us saying so. Institutions such as the Community of Madrid, the Catalan Food Safety Agency and the Spanish Food Safety Agency (AESAN) make it clear.
“Freezing is a safe method of food preservation that extends its shelf life and in turn helps to reduce food waste. If food is kept at constant temperatures of -18ºC or below, the microorganisms that cause food spoilage and can lead to illness are inactivated.”
Therefore, it is clear that when we freeze something, we are paralyzing the metabolic activity of the bacteria responsible for decomposition. During freezing, food hardly undergoes any significant alterations. In fact, there are foods, such as some vegetables, that are frozen and retain their properties better than fresh ones. And this is ideal when it can take a long time for food to reach the point of sale in the distribution chain.
As proper freezing keeps food safe for long periods of time, recommended storage times are based solely on quality criteria. These are the time limits for each food.
How to defrost safely
But not everything about freezing is positive. This process also has disadvantages: even in foods that tolerate it properly, it is common for water to be lost, which leads to the release of some nutrients stored in the cells.
The problem when defrosting. We have seen that freezing stops the growth of microorganisms present in food, but does not eliminate them. This means that, when defrosted, they become active again like The Walking Dead, as if they were awakening from a long slumber, and not exactly with good intentions.
If when they “wake up” they find a favorable environment — a perfect combination of temperature and humidity, increased by the thawing process — they begin to reproduce rapidly. In those vegetables that you have left out in the open or in that steak on the countertop, although at first glance everything may seem normal, invisible but potentially dangerous changes are already taking place inside. And the ideal environment for this to happen is outside the fridge: an ideal environment for them to grow.
According to food safety specialist Beatriz Robles in the book “Come seguro comiendo de todo” (Eat safely by eating everything), the microorganisms present in food before it is frozen can reactivate during thawing. Therefore, she warns that they should never be thawed outside the refrigerator.
“The temperature of the product will rise until it reaches those twenty or twenty-five degrees that are found in the kitchen, an oasis for the resurrected bacteria to multiply again without anyone rushing them”.
We are in a hurry, but there are other solutions. As the saying goes, haste makes waste, and in this sense, defrosting in the open air is a mistake, at least from a scientific and health point of view. If we are in a hurry and want to defrost food, there are other much more hygienic and healthy solutions.
What the experts recommend. It is best to defrost food slowly and in a controlled manner in the refrigerator. Specialists advise putting food in the refrigerator at least 12 hours before eating it. This method is the safest way to prevent food poisoning caused by bacteria such as salmonella, E. coli or Campylobacter.
How to defrost quickly and safely
What if I’m in a hurry? But if you don’t have time to use the fridge to defrost, you can always use a method that ensures the process and also does it in a short time. It’s about using the microwave and applying the water glass trick.
And the fact is that, although using the microwave to defrost is a quick and safe option, it is essential to do it correctly to avoid health risks. Therefore, it is advisable to follow a series of basic instructions.
First of all, you should always select the specific defrosting program on the microwave. This mode is designed to operate at low power, which allows food to be defrosted in a more controlled way.
To achieve a good result, it is advisable to place the food in a covered container, which helps to retain steam and promotes even defrosting. In addition, there is a very useful trick which consists of placing a glass of water next to the food; this helps to distribute the heat better and prevents some areas of the product from becoming too hot or starting to cook.
It is also advisable to defrost at two-minute intervals, turning or stirring the food between each break to ensure that it thaws evenly. In the case of large pieces, this technique helps the heat to penetrate evenly. For portioned products, such as steaks or croquettes, it is preferable to separate them during the process to facilitate more efficient thawing.
How to freeze properly
Having said that, after reviewing the benefits of freezing and the correct way to defrost food, there is one important aspect that we should not ignore. When freezing any product, it is essential to bear in mind a series of key recommendations:
You have to be careful when freezing. For safe freezing, you have to follow a series of guidelines that, in fact, are already recommended by AESAN:
- Use a 4-star freezer and make sure the temperature is below -18 °C.
- Freeze food as soon as possible, before its expiry date.
- Divide into portions to facilitate use and avoid waste.
- Do not freeze hot food or refreeze products that have already been defrosted, unless they are cooked at over 70°C for at least two minutes.
