The answer is surprisingly hard to come by.
So as a public service I am posting the following information:
One snack pack of M&Ms...
contains 16 M&Ms.
I rubbed off most of the food coloring from 14 of these...
Onto this paper towel.
So to answer the question, "What is the Minimum Daily Requirement of Food Coloring?" the answer is clearly, proven scientifically, "One M&M ought to cover it."
That is not even taking into account all the Titanium Dioxide used to color the white shell that is underneath the colored shell, or whatever food coloring is needed to make the chocolate on the inside such a rich chocolaty brown.