I doubt you've got a good data stream about sell-by dates, tho - the old and new have the same UPC generally. Maybe OCR of sell by stickers? And this doesn't help things that don't have dates, like produce.
Dang, I figured that stuff would have been included in the barcode. There must be some way to track this automatically because I doubt stores are managing their inventory on tracking this manually in 2020.
I've heard of them but I figured it was a periodic thing to make sure the stores automatic accounting aligns with actual stock to adjust for stolen, damaged, or misplaced product. I didn't think it was for checking expectations.