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There are different ways to extend the shelf life of food. Being able to consume a product outside of its harvest period and at ambient temperature is an undeniable asset for a balanced and ecological diet. Here is a lot of information on the main techniques of food preservation.
Dehydration and freeze-drying are used to preserve food by eliminating the water they contain. Here are some additional details.
Dehydration is a method of preserving food by removing water using hot air dryers. This method prevents the development of bacteria and molds. Dehydration can be used to preserve fruits, vegetables, meat and herbs for example. However, they may lose taste during the dehydration process. It is a long term preservation method at ambient temperature.
Freeze-drying is an expensive and complex way to preserve food. It consists in freezing food quickly and then dehydrating it using a low temperature vacuum. The vacuum preserves nutrients and vitamins. Freeze-drying is often used to preserve heat-sensitive foods, such as fruit and milk-based products.
The refrigerator and the freezer are essential tools in the kitchen for the preservation of food. Zoom on the different techniques of conservation by cold.
Refrigeration consists of keeping food at a temperature below 4°C to slow down the development of bacteria and mold. The kitchen fridge has been using this method of preservation since the 19th century. However, it is only of short duration.
Freezing is the process of keeping food at a temperature below -18°C to prevent it from spoiling. It can be done at home simply by respecting some rules of packaging and food safety. It is a long term preservation technique (several months) like deep freezing. The nutritional qualities of the products decrease with time, but they remain good to eat.
Fast freezing consists of rapidly freezing food at temperatures below -18°C. It allows to suspend the development of organisms responsible for the deterioration of products. Frozen foods can be kept for several months without losing their nutritional quality.
Microorganisms need water to grow. There are various methods of removing water to prevent their growth. Adding natural preservatives to food can also prevent it from spoiling.
Salting meat and fish is an ancient method of preservation. Salt removes water from food, which prevents the growth of organisms that cause deterioration. Salting is used to preserve meat and fish, which generally have a stronger taste. They can be preserved for several months
Smoking is an ancient method of preserving food. It consists in exposing them to smoke, generated by the combustion of wood or coal. The smoke destroys bacteria and molds, which allows a longer preservation. Smoked products, meat or fish, usually have a characteristic taste and smell. But they can lose nutrients during smoking.
Fermentation is a biological process that preserves food by transforming sugars into alcohol or acid. Bacteria or yeast convert sugars into acids, alcohol or gas. Fermentation has been used for thousands of years to preserve food. It gives unique taste to bread, wine, cheese, milk and fermented vegetables.
Zoom on the different thermal treatments of conservation.
Pasteurization is a thermal treatment used to inactivate the micro-organisms present in foodstuffs. It does not alter their organoleptic properties nor their nutritional value.
This technique was developed by Louis Pasteur in the 1860s and consists of heating food to a sufficiently high temperature for a specific period of time. This one does not however exceed 100 °C. Pasteurization is widely used in the food industry to produce milk or fruit juice. It makes it possible to preserve the food from a few weeks to a few months with the expenses.
The appertization or sterilization technique brings food to high temperatures (above 100°C) for a certain period of time. The aim is to eliminate all micro-organisms. This technique extends the shelf life of food. Indeed, canned food can be kept for several years at room temperature, depending on the product.
The sterilization of preserves can be done in different ways. Our Goût’stave retort allows for example to produce canned fruits, vegetables, meat or fish. The main advantages of sterilization are :
– To be able to eat fruits and vegetables out of season;
– Preserved nutritional qualities;
– The possibility of recycling the packaging;
– No energy expenditure for storage at room temperature;
– The limitation of food waste.
There are other methods of preservation, such as vacuum packaging or modified atmosphere packaging. Some future processes, such as ultra-high frequency (microwave) or ionization, are also being developed. Steritech offers you its expertise in sterilization and pasteurization. Contact us for more information!