Epicurious does YouTube videos with independent experts in their field to discuss quality products vs cheap products. [Here is the video on deli meats](https://youtu.be/LnA7Au-DLUM) in which their expert says the rainbow sheen is a result of a company adding too many phosphates to their deli meat to retain juices and bulk up the size of their meat. He mentions that at 3:52 in the video. 

If that’s true I think it’s sketchy that The Atlantic didn’t mention that in their tiny little article I just read that sounds more like a sponsored ad for the beef industry than informative news.