Vegetable or fruit pulp is produced by treating pieces of fruit or vegetable so as to obtain a purée； keeping the purée under agitation conditions at a temperature ranging from room temperature to 60° C. for 5-40 minutes, at a pH from 2.6 to 2.9； filling the purée into a flexible bag formed of a sheet material comprising three layers of food-grade plastic film and one layer of aluminium foil sandwiched between the layers of plastic film, creating a vacuum inside said flexible bag at a vacuum value of not less than 0.2 bar, then immediately sealing the bag and submitting it to heat treatment. The heat treatment step includes a first sub-step of 15-25 minutes duration to rapidly bring the package up to a temperature of 105° C., a second sub-step of 5-15 minutes duration to hold the package at that temperature, and a third sub-step of 5-15 minutes duration to rapidly cool the package down to a temperature of 4° C.
