Among the fresh-keeping methods of fish, there are food vacuum packaging machine vacuum packaging, adding deoxidizer packaging, filling carbon dioxide packaging and so on. These methods can effectively suppress bacterial proliferation and avoid lipid oxidation. However, the inhibition effect on autodigestion of fish body is not good.

The specific steps are as follows:

1. The alkaline solution with brH value ranging from 7 to 12 was injected into live fish. In order to improve work efficiency and make alkaline liquid immerse into fish body as quickly as possible, multiple injectors can be used together, a few parts and the main points are to inject the viscera. Suitable for the creation of water-soluble inorganic alkaline substances are: methyl carbonate, sodium carbonate, sodium bicarbonate, potassium pyrophosphate, sodium pyrophosphate, sodium nitrite, potassium nitrite and so on. Organic alkaline substances are sodium acetate, calcium propionate, sodium propionate, sodium citrate, sodium malate, sodium benzoate, etc. The concentration of alkaline aqueous solution is 1-20% (component).

2. The fish injected with alkaline aqueous solution are put into a container made of impermeable data and sealed with inert gases such as CO2 and N2. Inert gases refer not to chemical properties, but to gases that do not cause fish to metamorphose, such as helium, argon, hydrogen, carbon dioxide, nitrogen, methane, ethane, etc. However, from the point of view of economy and safety, carbon dioxide and nitrogen are still the best choice.

There are many filling methods of inert gas, such as vacuuming the container before filling the inert gas, blowing replacement method and filling the inert gas after removing oxygen from the container with deoxidizer. Generally, the higher the replacement rate of inert gas, the more obvious the complex action of inert gas and alkaline solution. This creation requires a replacement rate of up to 15% (volume). The sealed container materials used in this creation shall have outstanding non-permeability of inert gases and oxygen as described above. Material to satisfy this requirement are metal, glass and polyvinyl alcohol resin, vinylidene chloride resin, polyester resin, polyamide resin and other plastics. From the perspective of transparency, damage resistance and cost, plastic containers are the most suitable choice.

As for fish, whether freshwater or seawater, as long as they are alive, they can be preserved by this creative method.

Storage temperature is in the range of 5 - 10 C, which can keep fresh for more than 10 days.