ČSN EN 646

This document describes procedures for the testing of dyed paper and board intended to come into contact with foodstuffs. Some procedures depending on the foreseeable use of the material are given. Visual evaluation against a grey scale provides grading of the bleeding. For samples having significant different sides, a migration can occur from one glass fibre to the other and could lead to wrong interpretation of the fastness of one side. It is advisable to check these samples using large sampling procedure to prevent cross contamination of the glass fibre during the migration procedure. The procedure is described in Annex A. If lower limit of detection is required, this procedure could also be used.