There is described a method of producing a sealed package of a pourable food product from a substantially tubular precut blank of sheet packaging material with opposite open ends. The method includes the steps of feeding the blank onto a relative forming mandrel; sealing one end of the blank to form a container open at the opposite end; removing the container from the mandrel; and sterilizing the container before filling it with the pourable food product; and the method also including the step of preheating the container by heating the mandrel before sterilizing the container.