This is the CodeSystem that contains all the codes in Food and Drug Administration Food Facility Registration Numbers (http://terminology.hl7.org/CodeSystem/v3-fda-FFRN) and Food and Drug Administration Food Facility Registration Numbers (http://terminology.hl7.org/CodeSystem/v3-fda-FFRN). E.g. what you have to deal with if you get resources containing codes in either of them