Does anyone know specifically why Walmart recalled the GreatValue instant nonfat dry milk in the 10-pouch box?

As the cashier rang-up the box, a sign came across the cash register telling her the product was on recall and do NOT sell to the customer. She didn't know what was wrong with it and when I called the store today (Sun 7/5/09), they still didn't know anything. C/S did tell me I could return any I still had for a refund. I called all my relatives and informed them. I went on the Walmart/Sam recall site and nothing mentioned yet.