Occam's razor. The human digestive system passes most synthetic blue dyes undigested, hence the result. The blue dye mixing in the intestine with the yellowish-coloured bile makes the green colour. I notice this myself when I've consumed enough foods dyed with synthetic blue colourants (sometimes doesn't take that much) in addition to the raging upset stomach I get from it. Had they formulated it using some sort of natural (probably vegetable-based) colourant, it probably wouldn't have adverse effects like this, but it would require a significant amount and would get EXPENSIVE very quickly.
"the Halloween Whooper (sic) receives it's (sic) black color (sic) from A.1. Steak Sauce baked into the bun and less than one percent of food dye, according to a spokesperson for the franchise (sic)"
First of all, had they spent five minutes proofreading that copy, it might have increased the article's credibility a small amount. Unfortunately the damage has already been done by its having been published in the Mail.
While it may be less than 1%
by volume, the concentration of that allegedly <=1% synthetic dye is the key. The word "bold", presented in normal type here, uses the same amount of text space in this finished post as the word "
bold" in bold type, however the appearance of the types is attributed to the fonts' weights. Many items (including food products) that are "black" in appearance are really a very deep blue or purple colour and are dyed with such colourants. The photograph, while probably not conclusive, also shows it with a slight bluish hue.
I, for one, will not be ordering such a product. Burger King's "normal" products already give me digestive issues enough; never mind being adultrated by highly concentrated toxic synthetic colourants.
