Well, depends on the perspective you are conducting the assessment from....
For example, from a Food Fraud Perspective, its where you do an assessment to identify potential food fraud risks, i.e. looking at the material and the supplier/manufacturer. Actually if read further into the USP guidance, it provides guidance how to do an assessment and points to consider in the assessment. Included in the assessment is identifying gaps with your existing systems to prevent food fraud. If gaps are identified, then mitigation strategies need to be identified and all of this is set-up in a documented mitigation plan which needs to be maintained and periodically reviewed.
In addition to USP, some references I found helpful
FSSC 22000 issued guidance on Food Fraud Mitigation (April 10, 2018, Version 1, Number: 2171848)
Also, IFS (International Featured Standards) issued IFS Standards Product Fraud - Guidelines for Implementation
You might also find Food Fraud Institute (University of Michigan) helpful as well. They have webinars as well as certification programs around food fraud.
The FDA has not at this point published any guidance on EMA/Food Fraud, as far as I'm aware.
Point of note: both the FSSC 22000 and IFS references include questions/documentation for auditors which is helpful in preparation.
Hope this helps
