To an extent it will depend a bit on what you're doing, but a basic MS Word / Excel sheet with categories for the relevant people to contributes / sign-off for the following isn't a bad start:
Overview of project brief
Packaging
Process requirements
HACCP review
Regulatory requirements
Any specific product claims
Labelling content
Packaging/label design (if relevant)
Analytical requirements
Conflict of interest considerations
Health & Safety implications
Raw material status/availability/issues
You may also want to include things like customer credit limit, account setup etc if applicable to how your business works (I've found it can be helpful to put this in the same place as it forces the salesperson to get it sorted
).
At the end of the NPD process I'd also suggest having the customer countersign the recipe and process requirements (or an edited version thereof, if any of the information is proprietary), and of course also countersign the specification. That should define exactly what you are supplying to them, and by signing it they remove their ability to dispute it later (doesn't mean they won't try though...)