Tips for Vacuum Preservation

Some tips for proper vacuum preservation:

For the correct vacuum preservation of food, we always recommend packing the best quality products, paying particular attention to hygiene.

In the case of products containing liquids, it is recommended to let them cool in the refrigerator for a few hours (or in a blast chiller at temperatures below + 10°C) before packing them. Important: to ensure perfect hygiene of the food product, we recommend that you never reuse the bags. Remember to indicate the packing date and the name of the product on the bag!

Asparagus

Clean them carefully and separate them according to length and width, so that the searing time is as uniform as possible. Remove the hard part, wash and dry them. Then proceed with the searing by following the rules just described. After having cooled them, dry them again, taking care not to ruin them. At this point, you just have to put them in rigid containers, create the vacuum and freeze them.

Broccoli

The searing time for broccoli is about 3 minutes. Once seared, they must be well drained and kept under very cold water for about 6 minutes. Gently dry them, put them in rigid containers, create the vacuum and freeze them.

Artichokes

Clean them by removing the thorns and the hardest parts (if you want, you can freeze only the heart) and wash them thoroughly. To prevent parts from blackening by oxidation, immerse them in water, made slightly acid by a few drops of lemon juice or vinegar. Then, wash them again, dry them well and put them in the bags. Proceed with vacuum packing and freeze them.

Cauliflower

Before searing, it is necessary to divide the flowers. Then, they must be passed in boiling water for 3 minutes and cooled in cold water for 5 minutes. As for the other vegetables, dry them carefully, vacuum pack them and freeze them.

Brussels sprouts

Make sure they are very fresh: in this case they are a beautiful bright green colour. After eliminating any ruined parts and dividing them according to size (to sear them uniformly), wash them with cold water and sear them for 5 minutes. Then, drain them well and cool them immediately, passing them in cold water for another 5 minutes. Then proceed as usual with the packing.

Cooked food

Cooked dishes can be stored in the most convenient way: in bags (even on the plate on which they are placed) or in rigid containers.

Fruits and vegetables

The vacuum technique allows you to truly preserve an infinite number of fruit and vegetables, without incurring in those typical inconveniences of direct freezing such as, for example, frost which alters the characteristics of the product. As previously mentioned, however, it is necessary to ensure to use first-choice products. In the preliminary procedure for the vacuum storage of vegetables in the freezer, the searing phase is of fundamental importance, because it stops the inevitable degradation of these products, since boiling water and/or steam block the action of those microorganisms responsible for deterioration.

Mushrooms

To freeze them raw, simply clean them, wash them, dry them and, if necessary, slice them, depending on the type and size. Then store them in glass containers to prevent them from spoiling. If, on the other hand, you want to sear them first, proceed as follows: brown the mushrooms with a little seasoning (preferably margarine) in a large pan with a thick base, with the lid and on high heat for 3-6 minutes. Once the mushrooms have cooled down, pour them into a glass container with the sauce, create the vacuum and freeze. If desired, this system can also be suitable for stewed vegetables.

Aubergines

For this type of preservation, the most suitable aubergines are those which are firm and not too ripe. Wash and cut into slices or cubes. Immerse them in a container with cold water and a few drops of lemon or vinegar, which will avoid blackening. Now proceed with the searing for at least 4 minutes. Immediately after, pass them under the jet of cold water, dry and arrange them in the appropriate containers. After putting them under vacuum, proceed to freezing. Aubergines can be cooked directly without being previously defrosted.

Blueberries, strawberries, raspberries

These delicate fruits must be cleaned very carefully (not to spoil them), but without using water. Once the stem and leaves have been eliminated, they must be placed in rigid containers, stored under vacuum and frozen. Only after 24 hours can they be transferred into vacuum bags. Warning: before defrosting, remember to cut the bag!

Bread

The combination of vacuum-subzero temperature is particularly suitable for this type of product. Bread and all other food deriving from the baking process, both simple and elaborate (such as pizzas and sandwiches) preserved in this way, maintain all their characteristics of fragrance and freshness unchanged. It is advisable not to suck in the air completely, in order to avoid compressing the food too much. To defrost it, simply put the product in a hot oven!

Doughs

Excellent results can also be obtained by keeping the doughs used for the preparation of quiches or sweet cakes in a freezer. Avoid putting sugar or salt so that you can choose when preparing whether to make a sweet cake or a savoury dough. To preserve them, divide the dough into rectangular sheets about 3 cm thick, choose the suitable container, create the vacuum and freeze.

Peppers

Prepare them as if they were to be eaten at the moment: once opened, eliminate all the seeds and proceed with cutting, according to the recipe you intend to make. To eat them raw, it is possible to put them directly under vacuum in the freezer. If, on the contrary, you want to preserve them already cooked, it is necessary to sear them for about 2-3 minutes, even if the searing time will vary depending on the size and thickness. Now you can proceed with vacuum and freezing.

Pears, apples, apricots and black plums

Since diced fruit can be preserved only for a short period of time (about a month), it is not necessary to sear or wash them. Simply clean them thoroughly, put them in rigid vacuum containers and freeze them.

Fish

Fish notoriously deteriorates very quickly. For this reason, vacuum preservation is the best choice. It is of fundamental importance that the fish that you decide to preserve with this technique is absolutely fresh: therefore, make sure that during time between the moment of fishing and the purchase, it has been stored cold in special containers. Depending on the type of fish, the storage temperature varies: sea bass, carp, pike, cod, hake, sea bream, sole and tench can be stored at -25°C. Instead, fatty fish (such as herring, salmon, sardine, mackerel, tuna and trout) must be stored at a temperature of -30°C. Of course, crustaceans and molluscs can also be preserved with vacuum packing.

Peas

Peas can be stored both raw and cooked. In the first case, simply peel them and put them in the bags, then vacuum and freeze them. In the second case, however, it is necessary to cook them in boiling water for a couple of minutes. After this, eliminate the excess water, cool them under a jet of water. Now you just have to dry them very well and store them in rigid containers, following the usual rules of vacuum storage in the freezer.

Tomatoes

To freeze them it is enough to remember to remove their skin (therefore, it is good to choose rigid containers in order to avoid spoiling them) so that they can then be used as peeled municipalities.

Parsley, basil

Herbs in general can be preserved with this technique, you can be sure that they will be as freshly picked. If desired, you can already store them shredded or separated into bunches. Before putting them in the freezer in the appropriate rigid containers, they must be cleaned without using water.

Turnips

The ideal is to prefer products at the right point of ripeness (and therefore having a good consistency) and of medium size. Before storing them in the special vacuum bags, it is necessary to peel them, wash them thoroughly and put them in boiling water for about 3 minutes. Once cooled and well dried, you can proceed with vacuum and freezing. You can easily prepare the vegetables for the minestrone and put them all together.

Courgettes

It is not necessary to sear them before putting them in the freezer. Just wash them, clean them and cut them into rounds of about 2 cm. If you only need a portion and not all the contents of the bag, it is possible take the desired quantity and put the rest of the bag in the freezer ready to be eaten. Courgettes do not need to be previously defrosted, but you just need to cook them directly.

Defrosting

Defrosting can take place in different ways depending on your needs and time availability. You can choose to defrost the food directly in the pan, cook it in the oven (traditional or microwave) or, leaving it in its bag, in boiling water.

Vacuum storage

Vacuum packaging techniques

Vacuum packaging is a modern food packaging technique. It involves the extraction of the air contained in the package and then its hermetic closure. In this way the oxygen and all the chemical and bacteriological contaminants normally present in the air, such as polluting compounds, bacteria and moulds, cannot come into direct contact with the product.

Different vacuum levels can be used, adjusting the packaging machine, according to the characteristics of the product to be packaged until the almost complete extraction of the air and a residual oxygen value equal to one hundredth of the initial value. Any food product stored at low temperature in a rarefied and purified package, maintains its colour, aroma and nutritional value for longer. In short, all its qualities and all its economic value.

The possibility of using large plants to obtain this type of results, you can use small units, simple and easy to use at home to allow you to follow all stages of packaging.

What are vacuum packaging machines used for?

Hygiene and freshness of the product

The main enemies of product quality are the oxygen contained in the air and microorganisms (bacteria and mold). They are present everywhere in the environment and can be found in moulds, machines, operators' hands, etc.

Oxygen is an indispensable element for human existence, it is a very reactive gas and is able to combine with different substances contained in food products. When it reacts with food ingredients oxygen can cause negative changes in colour, taste and smell, compromising the quality and acceptability of the product.

Many of the microorganisms that can multiply in food are aerobic, this means that they need an adequate amount of air to live. Without it their proliferation is blocked and their activity of fermentation and degeneration of the food product is strongly inhibited.

In vacuum conditions and at low temperature only a few microbial species can develop and they are anaerobic.

The immediate evacuation of air from a package (therefore of the oxygen contained) ensures a longer conservation of any degradable food product. It also ensures a good presentation and real protection against accidental contamination.

The immediate evacuation of air from a package (and therefore of the oxygen contained) ensures a longer preservation of any degradable food product.

Production

Vacuum packaging a food product immediately after its production process is the best way to protect its quality and maintain its value.

Before the air starts to deteriorate the food product directly (by drying, oxidizing, changing the smell) or indirectly (by promoting the development of bacteria, yeasts, moulds and their metabolites), vacuum packaging can 'block' the quality of the product at the level reached during the production phase and keep it intact until the moment of consumption.

Sales unit

A machine capable of vacuum packing any food product into practical bags or trays can be the key to success of a sales unit for the following reasons:

  • Giving an additional service to the customer
  • Adding value to the product
  • Saving product shelf life during closing hours
  • Giving a product ready for free service

Extracting air from the packaging and putting the product in the best conditions of storage is easy and fast.

Restaurant

The preparation of elaborate and appetizing foods are very susceptible to damage that can be caused by air and time.

The taste, smell, appearance and texture change over time at a speed proportional to the amount of air available.

It is possible to stop or actually slow down these changes by protecting products made in a vacuum pack that prevents contamination, slow spontaneous deterioration and guarantees the products ready to use, fresh or cooked whether they are.

Fresh meats

The reasons why fresh meat deteriorates during storage are different:

  • Multiplication of aerobic bacteria
  • The red colour of the meat turns brown
  • Deterioration of the fatty parts
  • Surface dehydration or drying

The elimination of air in a vacuum pack allows the slowing down of all forms of qualitative degradation.

In a vacuum pack with a rarefied atmosphere and little oxygen, harmful bacteria cannot multiply and the lactic acid bacteria are allowed to take over and improve the taste and texture of the meat. The fat component does not deteriorate and the product does not dehydrate through evaporation or blood loss.

In the absence of oxygen, the meat darkens but this phenomenon is transient, not permanent and occurs when the meat is packaged immediately after cutting. As soon as the meat is exposed to air again, its colour takes on an inviting appearance for the customer.

Cooked Products

In cooked products (meat, fish or vegetables) the original microflora has changed due to heat treatment, enzymes naturally present have been denatured and fats are more exposed to deterioration. For these reasons, changes in colour, taste and smell can occur very quickly.

Vacuum packaging is particularly good for slowing down any degenerative phenomenon by eliminating oxygen and isolating the product in an airtight package. In this way the product does not take on any unwanted odour or dangerous contaminants.

Impairment

Baked Products

In cooked products (meat, fish or vegetables) the original microflora has changed due to heat treatment, enzymes naturally present have been denatured and fats are more exposed to deterioration. For these reasons, changes in colour, taste and smell can occur very quickly.

Vacuum packaging is particularly good for slowing down any degenerative phenomenon by eliminating oxygen and isolating the product in an airtight package. In this way the product does not take on any unwanted odour or dangerous contaminants.

Cheeses

All cheeses, hard or soft, are easily subject to fungal contamination. Spores of mould are often present in the air of the environment and can easily proliferate on the surface of the cheese due to the high moisture content of these products.

Vacuum packaging avoids this inconvenience which can damage the appearance and smell of these products through the almost complete elimination of oxygen which is essential for the growth of these micro-organisms. Vacuum packaging prevents the drying of the surface of the cheese and the oxidative changes that can compromise the smell and aroma of the cheeses produced.

Vacuum packaging and preservation at refrigeration temperatures are able to prolong the preservation of cheeses by allowing the distribution of whole or portioned cheeses.

Processed meat

The deterioration process of processed meat takes place in different ways: putrefactive phenomena, mould growth and greening can damage the preservation of processed meat. All these phenomena, whether chemical or biological, can be effectively combated through vacuum packaging that allows the elimination of air.

The most important characteristics of these products are their colour (pink or red), smell and fragrance. These peculiarities are strongly conditioned by the level of oxygen present inside the package. Therefore, excluding air from the vacuum pack is the best guarantee to maintain the quality of the product. Vacuum packaging of processed meat is a packaging technique that has long been used successfully by all major producers.

Main applications

The positive aspects of vacuum packaging can be rendered null and void by an inadequate choice of packaging material. Care must be taken when selecting and deciding on the plastic film or tray used for packaging. Plastics are all, in different degrees, permeable to gases and the vacuum in the package tends, physically, to accelerate the return of ambient air.

For long vacuum storage times, 'barrier' materials are required to prevent the entry of oxygen for the required storage time.

Orved with its production of pouches has numerous availability for users, the thickness of the material used is inversely proportional to the permeability of the various gases, the different types of pouches from storage to cooking cook and chil, in addition to the various sizes of bags made to facilitate any type of packaging. Finally, it is important to know that the passage of oxygen through plastic material is proportional to the storage temperature, the lower it is, the slower the phenomenon will be.

Protective atmosphere and vacuum packaging

Atmosphere modification or protective presents many important prerogatives in comparison to vacuum packaging, first of all it can be considered a more delicate technology because the food product is not stressed by crushing, the latter is compensated by the insertion in modified atmosphere.

The possibilities of formulation of the atmospheres are also so wide that it is impossible a specific and effective gas mixture for all products / packages.

Choices of packaging material

Atmosphere choice

This is certainly the most difficult choice to make when deciding to pack perishable food products in a Protective Atmosphere.

In this field of food technology there are many applications and it is always advisable to undertake adequate experimentation.

Experimentation is necessary to be able to define, by testing different gas mixtures, the variations in the fragrance and hygienic characteristics of a specific food product over time.

A useful approach could be to start with mixtures containing high percentages of carbon dioxide and nitrogen, making systematic and rigorous tests in order to find the best solution for each product system or package.

Storage times

It is difficult to give a precise answer to this frequent question because there are many factors that can influence the increase or reduction of storage times. The main factors are briefly described below:

  • The nature of the product, freshness and temperature at packaging;
  • The level of hygiene in the production plant and the equipment used in the process;
  • The steps taken to keep the product refrigerated until consumption (packaging and storage in the production plant, transport, shelves in the sales units, etc.).);
  • The quality of the materials used for packaging (bags, trays and films);
  • The precision of the packaging machines to reach the vacuum level and the quantity of atmosphere required for all types of product and packaging;
  • The quality of the packaging sealing;

Trade secrets

Wet or liquid products

When a wet product, containing free or liquid water, it is particularly important to use a bell-shaped machine first.

During the vacuum cycle a part of the water contained in the product is allowed to evaporate, the steam eliminated during suction is absorbed by the oil pump and therefore in the long run compromises effective operation, that's why Orved has included the H2OUT program, specifically for oil cleaning, in its packaging machines.

'difficult' products

The success of vacuum packaging depends on a number of factors that have to do with: the packaging machine and its potential; the packaging material used and the characteristics of the food product to be packaged.

Sometimes the shape, nature and consistency of food products can be a problem for packaging operations.

This is the case for granular or porous products. Due to their structure they contain and retain a fair amount of air between particles or within their pores. To effectively evacuate the packaging containing this type of product, it may be necessary to extend (using the extra-empty option) the packaging time or prepare the product in such a way as to facilitate air extraction.

Dusty products can cause problems during packaging. During air evacuation some dusty particles can be carried by the air out of the pack creating problems during the sealing phase or even reducing (over time) the functionality of the vacuum pumps. In this case the solution can be found by using the programs supplied with the specific orved machines (powders and spices), by adjusting the filling level or by placing special dust filters before the vacuum pump.