Originally Posted by IL1kebeer
Not sure if food coloring is sterile or even sanitized enough to ensure long term storage of the beer that it is added to. It could be, but I'd try to find out if I were doing this.
Get a fresh, unopened bottle of food coloring and sanitize the outside. You should be pretty safe. If you are worried, tell your buddy to drink them fast- say between 2-6 weeks after bottling.