Answer: Red #4

Some food dyes are completely synthetic (we’re looking at you, Yellow #5) and some food dyes are derived from natural sources. If you find yourself poring over the fine print of the treat you just fetched from the vending machine and see “Natural Red #4” listed among the ingredients, you’re enjoying a tiny bit of South American bugs with your snack.

Now, before you curl your lip in revulsion, be happy that you’re eating bugs, however microscopically, and not the chemical compound that was the original Red #4. The original Red #4 was banned for use in food stuffs (save for Maraschino Cherries, which are considered by the FDA to be decorative) and is only allowed for use in cosmetics and topically applied drugs and lotions. When the ban was finalized, food manufacturers turned to a source of non-toxic red dye that has a long and storied history: the South American Cochineal bug.

Spanish explorers long ago marveled at how brilliant the reds were in fabrics produced by the Aztec empire. Their secret was the Cochineal bug; they would dry and powder the bug and then boil the fabric in vats heavily saturated with the powder. This process has been refined over time and now in regions like Peru and the Canary Islands, workers gather Cochineal bugs and then mix the powder with an acidic alcohol solution to create carminic acid, which is then turned into carmine, which is then turned into Natural Red #4 for use in food products. Despite the fact that carminic acid was synthesized in a lab over two decades ago, it remains much cheaper to use the natural source.