1. Dry foods
Grains: e.g. rice, wheat, oats, etc. In vacuum sealed bags, these grains can be kept for a longer period of time. Generally speaking, rice can be kept for 1 - 2 years at room temperature. This is because the vacuum environment reduces the oxidation of grains by oxygen and also inhibits the growth of pests and moulds.
Pulses: At room temperature, pulses can last for 2 - 3 years. Pulses are rich in proteins and fats, which are susceptible to mould and oxidative rancidity under aerobic conditions. Vacuum packaging greatly reduces this risk by removing oxygen.
Dried vegetables and mushrooms: e.g. dried shiitake mushrooms, fungus, dried string beans, etc. These dried products can be stored in vacuum-sealed bags in a cool, dry place for 1 - 2 years. Dried vegetables and mushrooms have removed most of the water during processing, vacuum packaging further prevents them from absorbing moisture in the air and re-moisture, and inhibits the growth of microorganisms.
2. Cured and smoked foods
Bacon: These cured and smoked meat products can be stored in vacuum-sealed bags at refrigerated temperatures (0 - 4°C) for 6 - 12 months. Bacon and preserved sausages are inherently high in salt, which has a preservative effect, and together with vacuum packaging and refrigeration conditions, they can better maintain their quality. However, with the extension of time, the flavour of bacon and salami may undergo some changes and oxidation of the fat may occur.
Salted fish: In vacuum-sealed bags, salted fish can be kept for about 8 - 10 months under refrigerated conditions. The high salt content of salted fish combined with vacuum packaging inhibits the growth of bacteria and mould. However, salted fish contains high levels of nitrites, and prolonged storage may cause changes in nitrite levels, so it is also important to keep in mind the safety of consumption.
3. Fresh meat and seafood
Pork, beef, lamb and other red meats: if vacuum-sealed in the raw state, they can be kept at freezing temperature (below -18℃) for 6 - 12 months. At this temperature, microbial growth and enzyme activity are greatly inhibited. However, prolonged freezing can also degrade the quality of the meat, such as drying out and deterioration of the taste of the meat.
Poultry meat such as chicken and duck: can be stored in vacuum-sealed bags at freezing temperatures for 8 - 12 months. The fat content and tissue structure of poultry meat are slightly different from that of red meat, and the rate of oxidation of fat and changes in muscle fibres vary during the process of freezing and preservation.
Seafood such as fish and prawns: can be stored in vacuum-sealed bags at freezing temperatures for 3 - 6 months. Seafood is high in protein and unsaturated fatty acids and is susceptible to oxidation and microbial attack. Although vacuum packing and freezing can prolong its shelf life, too much time can still result in reduced freshness, loss of nutrients and odours in seafood.
