noun
red food coloring
Refers specifically to red food dye, often used in cooking and baking for coloring foods like rice, sweets, or pickled ginger.
おせち料理の紅白かまぼこには食紅が使われている。
Red food coloring is used in the red-and-white fish cakes for New Year's dishes.
この赤いご飯は食紅で色をつけました。
This red rice was colored with red food coloring.