I've had success getting food coloring out of clothes using vinegar and baking soda.
Add some vinegar to the food coloring stain and then let it sit for 10 to 20 minutes.
Then add some baking soda to the stain and take a toothbrush and scrub the red food coloring stain.
Then fill a bucket with some warm water and add some more baking soda, laundry detergent and some vinegar and let it sit for an hour or so.
Then scrub the stain some more and the food coloring stain should be out of the clothing.
If not then you may need to use some stain remover for clothing.
Hydrogen Peroxide can also remove food coloring from clothes but you may need to do it a few times to get the food coloring stain out.