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All the answers to your canned food questions


The tin can is a metal container that allows certain foods to be canned without adding ingredients.

It has become essential in our kitchens: not only in terms of speed but also it allows us to acquire products that are not in season.

What should you know about these canned foods.

1. How is the food canned?
The first step: the food is blanched to be then placed in the jars and is subjected to a heat treatment: called appertization .
Second step: the food is heated to a very high temperature (above 100 degrees). The time depends on their type. During this stage, the food will be devoid of microorganisms, enzymes and toxins. 
Third step: Canning : which can be in glass, metal, cardboard or even plastic.
The advantage of this canning is that the conservation can be done over several years.

2. How long can we keep them?
Let's differentiate between expiration date (indicated by: "  best before  ") And the best before date (indicated by"  best before  ").
The majority of cans have this 2nd indication, which means that the shelf life is longer. Thus, it is possible to consume the canned food after the indicated date without danger .
However, you should know that this one will have lost its qualities = its taste for example. In France, generally a tin does not exceed 18 months.
However, when the jar is open, it is recommended to consume it within 48 hours in the refrigerator.

3. How do canned foods lose some of their taste?
Some foods retain them lose part of their taste because thermal conservation denatures certain molecules. In addition, foods are bathed in a liquid high in sodium or in vinegar (for cabbage and onions), which causes them to lose their original taste and give them a more salty taste.

4. Are canned foods generally less nutrient dense?
Most of the time, the canning process loses a significant number of nutrients. Between the time the food is harvested and the time it is packaged, more than 5 hours (more or less) elapse. The perditions will vary depending on their food and nutrients .
Take the example of the canned tomato. It has a higher lycopene level than fresh tomato. (Lycopene is a natural pigment which gives the red color to watermelons, tomatoes…). Indeed, the losses observed during storage are greater than those observed during canning.

Regarding vitamins , they are destroyed up to 50% due to heat treatment. It all depends on the food, but antioxidants are often destroyed (because of the blanching process), beets lose about 63%, peas 45%, spinach 30% ...
Minerals are 50% retained (although bleaching is done with steam).
However, be careful with what is added during the canning process: the juice from canned food is often too rich in salt, which increases the sodium content of food.
On the other hand, lipids and fibers remain the same, just like carbohydrates and fatty acids which even improve the digestibility of food.

5. Are canned foods bad for you?
Canned foods are subjected to stability tests. There was the bisphenol A1 case in those boxes, but it is now banned. You should also check the outside of the can. If it is bulging, or has rust, it is strongly advised not to consume the contents.
Preserves should not be avoided, on the contrary, they allow you to find fruits and vegetables that are not in season and therefore be able to consume them all year round.
Price is also an asset since they are generally cheaper than fresh or frozen products.

6. Is it better to rinse food before eating it?
Take care to read the labels of the products: sometimes it is better to rinse them before consumption . Labels indicate whether the liquid can be consumed and whether the food needs to be rinsed. This is the case with legumes: it is preferable to rinse them to improve digestibility. Rinsing eliminates carbohydrates and complex sugars (which are responsible for poor digestion).

7. What is the juice in the canned food made from?
The juice of canned food is mainly water and salt. Sometimes even sugar.
Brine (which is the mixture of water and salt) helps keep food longer. It is mainly applied on fish and meats. Some of the salt migrates into the food, which increases the concentration of salt in it. For this reason, people with cardiovascular disease or high blood pressure are often discouraged from consuming canned foods.

8. Can we make preserves ourselves?
You can easily make your own preserves. However, great care must be taken with hygiene, which must be impeccable: to avoid contamination and the development of bacteria.
Sterilize your jars and make sure they are not damaged.
How to sterilize? boil your container in water and allow it to air dry. Do not wipe it off.
Lock up your food, preferably fresh and ripe, to extend its storage time. Then blanch them, then place them in your jar. Fill everything with a solution of salted and boiling water up to three quarters. Do not completely fill the container.
Then close your jar and place it in a pressure cooker filled with water at 100 ° C.
You will have to wait for the water to cool before taking out your jars and placing them in a dry and cool place away from light. It is best to consume them within a year of preparation.