Look at how they mix stock under the same SKU and see if you’re still confident perhaps that Peet’s coffee came from Peet’s or perhaps a third party seller used counterfeit — Amazon’s will put hem into the same punnet and pull out one where it’s from amazon or “fulfilled by amazon”.
Right now I’ve only seen it in electronics but I don’t buy much food that way. Amazon fresh is a different thing (all sourced / sold by amazon) so probably not a problem. Likewise oddball stuff (a low volume brand of tea) is unlikely to be worth counterfeiting. But mass market goods definitely are and the baby food example, while not amazon, is an excellent cautionary tale.