Abstract: A method and apparatus for controlled or modified atmosphere packaging of products such as foodstuffs, whereby the product (17) is weighed prior to or in the packaging machine and regulating the amount of gas inserted into the package in proportion to the weight of the product. User controlled variables may be used to determine the amount of gas to be injected into a package for a given weight or size of package, typically 1.5 to 1.75 liters of Carbon Dioxide per Kg of meat cut depending upon the type of meat, number/size of voids and bag size.