Store bought organ meats is still better than eating bagels, breads, crackers, pasta, donuts, etc.
Keep the meats very lean because toxins are mostly in skin and fat (chicken especially).
Most stores carry 'wild caught' fish. (which mostly means it's farmed raised and released to be caught 'wild'.
Oysters and clams are high in minerals and are very good for you (even from the store).
Don't go back to eating a crappy SAD diet because you can't find grassfed/finished local lamb (for example).
Btw, most lamb in the US is pastured, so is buffalo. They are not given pesticide, hormone and anti-biotic shots even if grain finished. The omega ratio is off and a few toxins (from the feed) are stored in the fatty tissue and organs (mostly kidneys) but that's about it.
Rotate buffalo/lamb and seafood, stay away from chicken as much as possible, the ratio is the worst and they're all fed soy and arsenic (for rapid growth).