Orion promptly responded to my original inquiry, saying that they had not been aware of the issue and would look into it. I've had no further contact from them.
The supplier's website continues to display the now-expired ISO 13485 certificate.
My assumption is that for one reason or another, the certificate already was not in the process of being renewed at the time of my inquiry, and Orion regards the matter as no longer their problem since the certicate now is expired.
We had some lab testing done on the most recent five batches of product provided to us. Such testing of course didn't prove sterility, but it did give us some indication that at least those product batches weren't wholly nonsterile.
We've had no downstream contact from either the supplier or FDA regarding a product recall or other field action.
We've made several revisions to our supplier control procedures, and we're working on further changes to improve control.