Abstract: A system for checking the authenticity of a product, according to which the product is provided with an identification, the information of which is read out by a detector and is transmitted to a database via an information network and is compared with information stored there, wherein a decision regarding the authenticity or inauthenticity of the product is generated as a result of the comparison and the result of this decision is signaled at the location of the product. The product is a packaged foodstuff and the detector is arranged in a refrigerator in which the product is placed. The invention also relates to a system for optically identifying from above products on a transparent shelf surface.