On an annual basis, laboratories testing chemical residuals (pesticides, heavy metals, and antibiotics) need to update and verify their standard operating procedures. The verification may be accomplished by establishing and confirming analytical merits, including but not limited to items such as instrument detection limit, instrument quantitation limit, method detection limit, method quantitation limit, recovery, precision, and accuracy. The analysis of certified reference materials, when available and applicable, will be required. Laboratories may be required to participate in external proficiency test program(s).

Laboratories testing Salmonella, Listeria monocytogenes and Total Plate Count must keep participating in a proficiency test program administered either by the AOAC International or the American Proficiency Institute, have a satisfactory analytical result, and have the result sent to the Program Manager directly from those institutions.