Vacuum-packed cooked food must be -40 degrees quick-freezing, and then -18 degrees environmental preservation, in order to save about three months. Cooked food products if you add a preservative, the use of vacuum packaging can generally save 15 days, if it is a low-temperature preservation can be stored for 30 days, but if you do not add a preservative, that is, the use of vacuum packaging and low-temperature preservation can only be stored for three days, after three days, both the texture and flavor will be much worse.