A method for packaging products, such as any solid or semi-solid product, utilizes a horizontal form, fill and seal (HFFS) system, coupled with a method for subjecting the packages to positive pressure differential while packaging. In the HFFS system, product receiving cavities are formed in a lower film, with each product being arranged in a respective cavity. The loaded product receiving cavities are positioned in a sealing unit, with an upper film above the product cavities. The sealing unit is closed and a lower chamber of the sealing unit is pressurized to force the lower film against the product, while the product abuts a standoff member, in order to remove existing headspace. After minimizing the headspace, a sealing head seals the upper film to the lower film about the product receiving cavities. Thereafter, the pressure is released, the sealing unit is opened and the package can be further processed.