vacuum packing frequently asked questions

Vacuum bags and any packaging should be stored so that it doesn't get contaminated by raw meat. Cooked meats must be handled in hygienic conditions and should be packed immediately after cooling. Vacuum packed cooked meat cannot have a shelf life greater than 10 days from the date of cooking. Extending the shelf life beyond 10 days increases the risk of growth of non-proteolytic C. botulinum. The vacuum packed cooked meat should be stored at or below 3°C at all times during its shelf life. Temperatures above 3°C will encourage growth of Clostridium botulinum and other bacteria. It is good practise to introduce a labelling system with cooked date and use by date. Vacuum packaged cooked meat needs to be protected from external contamination from raw meats and poultry and therefore should be handled with the same care as open cooked meats. More information can be found at the Food Standards Agency website.

Using a vacuum packing machine is the best way of storing your meat. By removing the oxygen, meat stays fresher and retains its flavour for longer. Vacuum sealing and freezing reduces growth of bacteria and slows down enzyme brake down. Freezer burn is something that occurs when meat is stored in a freezer for long periods, vacuum packing totally eliminates this along with moisture crystallization. Before vacuum packing meat, it is advisable to chill the meat to about 4 degrees. This makes the meat easier to cut and it also retains its shape better when being vacuum packed. Remove any sharp bones that can puncture the vac pack bag, you may need to wrap the item in a thick bag first. Remember, you can stop the vacuum process at any time to prevent the meat from being crushed.

Fresh Fish and Seafood for Freezing

Using a vacuum packing machine is the best way of storing your fish and seafood. For best results, it is of vital importance that the fish or seafood is as fresh as possible and that it has been kept constantly chilled. The length of time that fish and seafood have previously been held on ice or chilled storage vastly affects the storage time once it is frozen. If you intend to freeze fish and seafood, you should buy it as fresh as possible, it should also be kept as cold as possible right up to the point at which they are put into the freezer. Experiments show that lean fish held for two days on ice will last up to 12 months in a freezer before any loss in quality, clams and oysters will keep for 3-4 months and crab and prawns will keep for 9-12 months. The same fish held for seven days on ice can only be stored for 2 months in a freezer before any loss in quality, seafood held for two days on ice will last up to three times longer than the if held on ice for seven days.

The leaner the fish, the longer it can be stored in the freezer. However, the quantity of fish oil contained in the fish can affect this rule, the more fish oil - the less time it can be stored. A description of oily and none-oily fish can be found here. Vacuum packing drastically reduces the breakdown of oils present in the fish. Do not underestimate how important it is to use good quality vacuum sealer bags which are impermeable. Cheap plastic bags offer very little protection to fish and seafood products compared to quality PVC vacuum sealer bags.

Fish can be filleted before vacuum sealing, although this can also affect their flavour. None-filleted fish will keep its flavour longer than filleted fish. If filleted, pack them two fillets to a bag with the skin to the outside, this is not so important if you plan to eat the fish relatively soon.

Already frozen fish and seafood can have its freezer life extended by vacuum packing it. Simply put several holes in the existing wrapping, place the fish plus the wrapping into a vac pack bag and then vacuum pack it, this will remove the air from the existing packaging. 

Fresh Fish and Seafood for the Refrigerator

Fresh fish does not store very well in the refrigerator as the flavour of the fish deteriorates quickly. Smoked or cured fish will keep better in a fridge if it is vacuum packed as this prevents it from drying out. Use a polystyrene tray to put the fish on and then put the board into a vacuum bag before vacuum sealing.

Sauces

Vacuum packing helps to retain the consistency and more importantly, the flavour of sauces. By removing the air, it reduces oxidation and your sauces will keep their flavour better than conventional storing methods. Sauces can be reheated when needed by placing in a pan of very hot but not boiling water. By doing this in a vacuum sealer bag, moisture is contained within the bag and not lost to evaporation which results in a better consistency.

Casseroles and Stews

Reheating casseroles and stews contained in a vacuum sealer bag and in a pan of hot but not boiling water, prevents them from drying out because the moisture is retained in the bag. Additionally, as the heat is evenly distributed to the top, bottom and sides - no stirring is need which prevents the meat and vegetables from breaking up ensuring the reheated food looks as appetising as when it was first made. Making large quantities can also save you time and money as it is usually cheaper to buy larger quantities of ingredients and usually takes not much longer to produce 2 portions as it does to produce 8.

Once you have made your a sauces, casseroles and stews, you will need to chill it before vacuum packing it. Chilling it makes it thicker which prevents any liquid from being sucked into the vacuum sealer machine. To prevent food coming into contact with the opening of the bag and stopping it being sealed, turn down the top 5 cm. You can use a measuring jug to put the bag in to use as a stand. When ready to vacuum pack the food, it is recommended to raise the vacuum packing machine up on a deep chopping board, this enables better handling of the bag by keeping it below the machine and preventing liquid from entering into it. A full vacuum is not required for this purpose, just enough to remove the air to prevent it from bursting whilst reheating. The Freshield Elite II Vacuum Sealer is perfect for this as you can press the bag stop button to stop the vacuum and start the sealing process. To reheat the sauce, casserole or stew, place the sealed vacuum pouch in a large pan of very hot but not boiling water. Ensure contents are thoroughly reheated before eating.

Fresh Vegetables

It is not advisable to vacuum pack fresh vegetables for refrigeration for any length of time. The vegetable is still alive  and will continue to ferment, resulting in a slimy mess when you come to use it. It is much better to freeze them. Blanch your vegetables prior to freezing, this will kill the vegetable and lock in the colour, flavour and freshness - it is recommended to buy a good book on freezing vegetables. Delicate vegetables like peas and beans can be simmered for 30 seconds then dipped in ice cold water to prevent further cooking. Pat dry, then vacuum seal. To cook them, microwave them in the bag for around two minutes, you can also boil in the bag for around 5 minutes, try seasoning with salt, pepper and butter before vacuum packing them. The flavours are locked in the bag and are not diluted in water. Root vegetables need to be blanched for approximately 5 minutes, cut vegetables to a uniform size so that they cook evenly. Do not freeze your vegetables without blanching them first.

There are many times when we have an abundance of seasonal produce and vacuum packing can help with this. Strawberries and raspberries are a household favourite but have a very short shelf and they can be stored in several ways. Storing your strawberries in a vacuum container in the refrigerator can extend their freshness for several days longer. By removing the oxygen, it greatly reduces the growth of bacteria and the breakdown of enzymes resulting in a longer shelf life. Vacuum containers are an ideal way to store soft fruit in the fridge, as unlike vacuum bags they do not crush the fruit when being vacuumed. If you intended to freeze fruit, you can do this in a vacuum sealed container or in a vacuum sealer bag. Fruit is simply put in the vacuum container and vacuumed with a sealer machine or a manual vacuum pump. If you wish to use vacuum bags, you may need to pre-freeze the fruit before vacuuming to stop it from being crushed. First place the soft fruit into a vac pack bag then freeze it over night. Remove from the freezer and vacuum before putting it back in the freezer again. You can also use this method for cooked fruit like apple sauce or stewed fruit, this also prevents liquid being drawn into the vacuum sealer machine.

Hard cheese vacuum packs better than soft cheese, an un-grated Parmesan retains its fresh flavour for months when vacuum packed in a refrigerator. It is also possible to vacuum pack grated Parmesan but be careful using softer cheese like cheddar as it sticks back together. Cheeses are very prone to surface mould as well as drying out, by vacuum packing them it prevents this from happening as well as retain the full flavour. Most cheese can be vacuum packed and will store in the fridge for 3 times longer than conventional storage methods.