Based on your description I would take this approach:
1. Set-up a barcode that contains the item code and use-by date within it, so both pieces of data can be captured and tracked in one swipe.
2. The warehousing software would automatically mark the item as ready for release in the Back Order Control Centre as soon as it was scanned. There would be no need to manually mark items off paper pick-lists.
3. Allow easy look-up of scanned items based on customer, order and use buy date.
4. Because the item must be found on the order and the quantities have to also match, the warehousing software won't let the order go through if the wrong item have been scanned or items are missing.
Issues I see:
Locating scanning and computer equipment able to reliably deal with the cold temperatures.