A method and apparatus for identifying manufactured items in containers, where each container is suitable for containing two or more units, and where the method comprises the steps of: associating each unit with a unique unit identifier, uniquely identifying each unit, allocating two or more units to be contained in each container, uniquely identifying each container, for each container, determining one or more ranges of unit identifiers of the two or more units allocated to the container, and storing, in a database, a container identifier for each container, each container identifier being coupled, in the database, to the one or more ranges of unit identifiers of the two or more units allocated to the container. There is also provided methods and apparatus for authenticating, tracking and tracing the units.