DIN EN 646:2019 "Paper and Cardboard in Contact with Food - Determination of Colour fastness of Stained Paper and Cardboard" is a standard published by the European Committee for Standardization (CEN) that specifies a test method for colour fastness of stained paper and Cardboard for use in contact with food. The standard provides two test procedures: Procedure A: Suitable for long-term exposure to materials such as Food Encasement. Procedure B: Suitable for short-term exposure, such as napkins, kitchen paper, etc. The test detects whether stained paper and Cardboard bleed after contact with food through visual evaluation. This standard helps ensure the safety of food contact materials and prevents the migration of stains into food.