GB/T 31479-2015 "Determination of Color Fastness of Dyed Paper and Paperboard in Contact with Food" specifies the method for determining the color fastness of dyed paper and paperboard in contact with food, applicable to various types of dyed paper and paperboard intended for food contact. It defines the preparation requirements for three immersion media: water, acidic solution, and alcohol solution. After cutting, samples are immersed separately, and color migration is evaluated through a combination of visual assessment and instrumental measurement. Relevant standards for color difference determination are referenced to ensure the accuracy of color fastness test results, providing a basis for safety control of paper used in contact with food.