Question
what is an organc auditor? what do they do?

Answer
From what I understand, organic auditors may arrive unannounced at any growers, processors, packagers, or warehouse operators producing food that is to be marketed as Organic.  

They can test everything from compost to the streams running off a farm wherever food is organically grown, and check all records of farm and processing practices that effect crop and product purity and integrity.

They review records to assure that all ingredients used were organically grown, and make sure that the records are available for organic inspectors, assuring they have followed the uniform set of standards used for Organic Certification.

Records include such things as organic farm and processing plans; field maps; field logs; journals; calendars; records of harvest, storage, and sales; animal health reports; receipts; invoices; billing statements; bills of lading; inventory control reports; production reports; processing reports; handling reports; facility diagrams; process flow charts; questionnaires; affidavits; inspection reports; laboratory analysis reports; minutes of meetings; personnel files; correspondence; photographs; and other materials.

These records record the production, harvesting, handling, and processing practices of all certified organic products and provide the ability to track the organic integrity of a product back to its source field on a particular date of harvest or to a particular set of traceable ingredients.

Records are usually kept for 5 years beyond their creation and be must be accessible to organic inspectors in order for a business to remain organically certified. These records create an "audit trail" for the organic inspectors and Organic Certification.