But, there are other things at work.
1) Many suppliers have in fact raised their prices, some for just reasons, others due to gouging and monopoly positioning (see Canadian Dairy Council)
The retail price, all other things being equal, is a percentage mark up over wholesale cost; so if the supplier adds .40c, the retailer may up the end price by .80c.
2) There absolutely has been some margin bloat, you can see that right in the public financials. Its less than people think, but it is there.
3) Shink is up big time (loss due to theft in this case, as opposed to spoilage), that cost is being passed through, and its a bit of a negative feedback loop.