It consists of packaging food without having contact with the external environment.
In the case of pumpkin puree, after cooking in concentrators to increase Degrees Brix from 6-9°, most commonly found in nature, (Brix is a measurement of the dissolved sugar-to-water mass ratio) to 20-22°, the product enters a line that makes it sterile, the bacterial loads go to zero, then without contact with air it fills and closes specially prepared sterile bags.