A quick google search for warehouse management systems with logic for tracking expiration dates brought back [this system](http://www.asapsystems.com/warehouse_management_systems.php). While it's not a pantry system and is in fact intended for much larger operations, it does track products and locations, includes "Tracking for Expiration Dated Food", and is mobile. I've never used it so I can't attest to the truth in the advertising.

Relevant search terms in this case would be 'warehouse management' or 'asset management' software. I don't have the ability to look up if there's a specific patent on the subject currently.