There are plenty of good ways to do it, but the problem is there’s always going to be somebody that looses out. Of course none of those approaches are ”perfect” but even if somebody did come up with a perfect approach you can be certain that a bunch of issues will be manufactured overnight
Check the video out - those aren't "manufactured" issues - the reality is that such devices can only perform a surface level check at best - and even then, telling close things apart gets challenging. If you think you can do better, please explain how such a device could work?
It's quite simple: Coca Cola, Crisps, Mars Bars, Bacon, White Bread ... all these things you assign a red. Broccoli, Carrots, Nuts and Beans get a green. Everything in between gets orange. Pretty much all meats and dairy will end up in the orange segment which will upset this very powerful sector. The pork guys want you eating pork at every meal if possible.