You'll find that that barcode is the same barcode as the product but with some numbers on the end that include the price, a reason code for the markdown and other assorted stuff.
Indeed. I would also suspect each of those are unique so that they couldn't sell the product after a certain date/time for really perishable food. But still, this is not a standard EAN barcode and their readers can read it.
I've done quite a bit of work with barcodes, having to deal with many shipping companies and their requirements for labels, manifests, etc. One had a very specific requirement in the coding of a certain label: every scanner could read it but it wasn't encoded the most efficient for the data presented. (Code 128 sets)