DIN EN 648:2019 "Paper and Cardboard in Contact with Food - Determination of Fastness of Fluorescent Whitening Paper and Cardboard" is a standard published by the European Committee for Standardization (CEN) that specifies the test method for the fastness of fluorescent whitening 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 fluorescent whitening paper and Cardboard bleed after contact with food through visual evaluation. This standard helps to ensure the safety of food contact materials and prevent the migration of fluorescent whitening agents into food.