A mixing system includes a portioning device for sequentially supplying batches of a specified quantity of foodstuffs at a supply location. A mixing device includes a number of mixing chambers which can be sequentially aligned with the foodstuff supply location. A dispenser is provided for dispensing measured quantities of an additive at an additive supply location spaced from the foodstuff supply location. The mixing chambers are movable about a closed path so as to be sequentially brought into alignment with the foodstuff supply location and the additive supply location. A control system controls operation of the portion device, mixing device and dispenser. A packaging device is disposed downstream to the supply location and below the mixing device for packaging the batch of foodstuffs in a bag. Each mixing chamber is operable above the packaging device to discharge its contents into the packaging device.