From your Norwalk, CT store. We've had bad milk twice in the last four months.
This most recent was purchased 7/19, with a 'sell by' date of 7/26. The milk, not yet sour, curdled and was grainy on date of purchase. In looking at the one gallon container, that same graininess is evident with slight curds adhering to the container above the milk. The sour milk of about four months ago was, simply, the milk being quite sour the day after purchase.
I'm not going to go through the nuisance of sending receipts or pictures, etc. I don't want anything back from Costco -- just pointing out something you should know.
Product or Service Mentioned: Kirkland Signature Milk.
Reason of review: overall good.