http://www.btps.ca/files/PDF/MSDS/red_food_color.pdf

In addition to personal telephone confirmation by the lab folks at McCormick.

If by "depending on where you look" you mean random internet crap, yes, I'm sure you can find anything. Here's a lovely site that is case in point: http://grannyspantry.blogspot.com/20...colouring.html
The numbers 3 and 40 are flipped even though the hyperlinked reference is correct.

I'm sure I couldn't say the sun rises in the east without you saying I'm wrong, Ian. "Why" is a mystery to me. Regardless, I'd hate to have people use McC red and fail to get an ortho emulsion. That just feeds the myth that making emulsions is too hard/random/unsatisfactory/expensive to even try.