In this post we are going to talk about vacuum packaging, and more specifically about the different bags that exist to carry out this process and the factors that we must take into account when selecting them.
Why do we vacuum package food?
Foodstuffs are biological and sensitive substances, and they are affected by both internal and external conditions.
Among the internal factors we have: the composition of the product, water, the pH, the cellular respiration and the type and quantity of microorganisms.
Among the external factors we have: the temperature, the hygienic conditions, the atmospheric gases and the processing methods.
Food is basically spoiled by chemical/biochemical spoilage. Spoilage occurs when micro-organisms found in raw materials, ingredients or the environment are present.
Therefore, the way the product is handled before storage is of great importance for its preservation and shelf life. Microorganisms surround us everywhere, such as our skin, tools or the air itself. It is therefore essential to maintain rigorous hygienic conditions throughout the food processing chain.
The way the product is handled before storage is of great importance for its preservation and shelf life.
Vacuum packaging
Vacuum packaging is a natural food preservation technique that consists of extracting the air from the bag or container, eliminating oxygen, the main factor in food spoilage.
Removing the air surrounding the product inhibits the growth of bacteria, mold and fungi, since they need oxygen to grow. Once the air is removed and the bag is sealed, oxygen levels continue to drop while carbon dioxide levels rise. This reduces the growth of spoilage organisms, allowing the shelf life of the product to be extended.
Thus, with vacuum packaging not only we protect food from external influences, but we extend shelf life by 2 to 4 times.eguimos: extender la vida útil de cualquier producto perecedero entre 2 y 4 veces mientras lo protegemos de influencias externas.
The benefits of vacuum packaging according to the type of food
Depending on the type of food, vacuum packaging will favor different aspects.
Raw and fresh
In the case of raw and fresh foods such as: meats, vegetables, pasta, fish, etc. Vacuum packaging favors the following aspects.
- We isolate the product from all contaminating agents.
- We extend the shelf life.
- We avoid losses due to drying out.
- We avoid odor mixing.
- If we freeze the vacuum-packed product, its shelf life is extended.
Cured
In the case of cured products with a long shelf life, such as sausages, hams, marinated products, etc., Vacuum packaging favors the following aspects.
- The shelf life is extended.
- They do not lose weight or dry out.
- It allows storage without mixing odors.
Traditionally cooked foods
Finally, we have the case of traditionally cooked foods. That is, foods that are handled by traditional cooking and then packaged following the Cook & Chill process.
The Cook & Chill process consists of cooking a product and then reducing the temperature of the food significantly. After cooking, the product is practically uncontaminated so that in the following two hours it is important to reduce the temperature to core to prevent the development of microorganisms. Finally, vacuum packaging is carried out for subsequent storage at temperatures between 0-2ºC / -18ºC.
In this case, vacuum packaging favors the following aspects:
- It facilitates the work in the preparations.
- It extends the shelf life of the product.
- It reduces the risk of product loss.
- Food waste is reduced.
Packaging is normally done in bags. Although it can also be done in reusable containers specifically designed for this purpose.
The different types of bags
The packaging material is of crucial importance as it determines the results obtained by vacuum packaging. Different materials and combinations of these are used depending on what is to be achieved, for example:
- Mechanical resistance.
- Vapor barrier to avoid weight loss and dehydration.
- Gas barrier.
- Gas permeability.
- Anti-fogging properties (the inside of the material must have a surface that does not allow the formation of water droplets that reduce transparency).
- Sealing properties.
- Transparency or light permeability.
If the vacuum-packed product is to be cooked sous-vide, it is important that the bag withstands the temperatures required for cooking.
Las bolsas de envasado al vacío presentan muchos usos diferenteVacuum packaging bags have many different uses, the most important of which are the following:
- To avoid drying of fresh produce.
- To protect dry products from humidity.
- To prevent certain products from absorbing bad odors from the environment.
- To prevent the growth of microorganisms, fungi and aerobic bacteria.
- To portect products from light, oxygen and other gases.
- To prevent certain products from losing their aroma
There are different types of vacuum bags depending on the thickness of the bag and the proportion of polyamide and polyethylene. The Polyamide gives the bag its airtightness while the Polyethylene allows its sealing. The thicker the bag, the more resistant it will be. However, it will lose its transparency properties more quickly.
Vacuum packaging bags can be for preservation or for cooking, depending on their micronage and the materials they are made of:
For cooking
Cooking pouches are those that can withstand high temperatures up to 120º during long and low temperature cooking. They can be used for steam sterilization and have a high barrier to oxygen and water vapor.
These bags are used in steam ovens, water baths or in Roners (water circulators). Generally, they are used to always maintain a constant cooking temperature and thus achieve high precision in the cooking times of each food.
For preservation
These bags are suitable for food preservation, as well as for pasteurization at temperatures up to 80º. Depending on the micronage, these bags can be more or less time at 80º.
They are ideal for packaging fresh products, so they can be used to store and preserve fruits, vegetables, meat, fish, sauces and other liquids. On the other hand, they have optical properties, transparency and high resistance, allowing them to be kept in the freezer without any problem.
Metalized bags
These are vacuum bags laminated with a neutral front side and a gold or silver metallized back side, giving the product a much more appealing and eye-catching image for the end consumer.
Traditionally, metallized bags have been used for slicing and packaging high quality sausages, however, their use is becoming more and more widespread to distinguish the most select pieces of fresh meat and other food products.
Bags that are completely metallised, i.e. without a neutral part, are ideal for sterilisation and pasteurisation. They also protect the product from light, as light could deteriorate its colour and give it the appearance of being poorly made.
Glass containers
Es otra alternativa para dar una segunda vida a los botes de cristal, siempre y cuando hayamos limpiado bien los tIt is another alternative to give a second life to glass jars, if we have cleaned the jars well and they are in optimal conditions.
Compostable bags
Finally, we should mention compostable bags. There is a growing concern about plastic consumption and the European Union has already established certain standards and guidelines. Especially in the use of those plastics whose utility responds to the 1 single use and is generally easily replaceable by another object or another material. This is for example the case of supermarket bags, which are easily replaceable by cloth bags or shopping carts.
In the case of the bags, we use for food preservation and cooking, the replacement is not so simple. As we have just seen, they require certain specific characteristics to fulfill their functions.
However, even in this field, alternatives are beginning to arise, such as compostable vacuum bags for food use. These are specifically designed to withstand the temperatures of sous vide cooking but can also be used to store any type of food. These vacuum bags can withstand temperatures up to 85°C for 12 hours. They are a versatile, durable, and sealable eco-friendly alternative to conventional packaging, and are very suitable for packaging foods such as fresh produce, refrigerated foods, meat and poultry. It should also be mentioned that the price of these bags is higher than that of conventional bags.
In conclusion, we can say that the technique of vacuum packaging food brings numerous benefits such as extending shelf life and protecting the product from external influences. But the selection of containers or bags should be made knowing both the characteristics of the product and its intended use.