An USDA-accredited organic certification agency (i.e., the independent third-party) verifies the following claims (none of these claims can be verified for non-certified organic pet food products):
1. Organic status of ingredients
2. Sourcing of ingredients (e.g., countries of origin, human-grade vs. feed-grade quality)
3. Qualities of ingredients (e.g., antibiotic-free, hormone-free, GMO-free)
4. Omission of toxic synthetics during growing and handling of ingredients (e.g., no use of synthetic pesticides, GMOs, antibiotics, or hormones)
5. Omission of toxic synthetics during the manufacture and storage of pet food product (e.g., sanitizers, pesticides)
6. Processing details (e.g., what temperatures are used during dehydration)
The organic certifier has access to all of the records of the manufacturing facility and of every single production batch. These records have to be available for re-inspection if necessary for 5 years.
Nobody can guarantee any of the claims listed above for non-certified organic pet food products, because records do not have to be disclosed to anybody who is not associated with the pet food company.
You may see that organic certification of pet food products substantiates a manufacturer