In advance of Halloween, Burger King unveiled a new whopper with black buns and A1 steak sauce in late September. The company called it the Halloween Whopper.
Fans of the Whopper were excited to try the new menu item, but after only a few hours, they were left with more than memories and an Instagram picture — some claim their faeces had turned greenish blue, as first spotted by First We Feast.
Right away, people started posting the news on Twitter:
Public service anouncment! Do not eat the new Burger King Halloween Whopper. It will turn your poop green. Other than that….pretty good.
— Captain Insaneo (@AbateadamAdam) October 1, 2015
Yesterday I ate Halloween Whopper with black bun at Burger King. When I looked at my poop it turns green. LOL!
— Kirk (@iNCREDiPiNOY) October 3, 2015
so. the black bun burger king whopper made my poop green.
— kat (spooky edition) (@andouilles) October 3, 2015
Some people are saying the new shade could last multiple days.
One Twitter was less than amused and pointed out that the black bun contains nearly twice as many chemicals and ingredients as the normal sesame seed bun. These ingredients include FD&C Blue #1 and FD&C Yellow #6, which combined, would give you that blue-green colour everyone is seeing.
It’s not surprising that food dye could change the colour of someone’s stool. An unusual colour is “almost always due to food colouring or food additives,” according to Children’s Hospital in Colorado, and even vegetables like spinach or kale can turn faeces green, according to the Mayo Clinic.
Tech Insider reached out to Burger King about the issue, but has yet to hear back. Burger King told ABC News that the black bun contains less than 1% of food dye and Huffington Post pointed out that in its nutrition information, Burger King states that the dye amounts were “within the safe and Acceptable Daily Intake (ADI) approved by the Food and Drug Administration.”
But that hasn’t stopped the concerns and feedback from rolling onto Burger King’s Facebook page.
Yet for some people, this seems to be an added bonus.
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