Since I was up early this morning doing lesson plans I decided to do a little research on your question. I found something on the
ASPCA: ask the animal poison control center.
And this is what it said about the food coloring
Food colorings approved for human consumption are also safe to be used in foods for pets. We do have to point out that using large amounts of food colorings can sometimes cause changes in the color of the pet's urine, however, but this would not affect the pet's health.
Good luck making your cake
