Analytical testing and laboratory determination for analyte or quality constituent shall be based upon the appropriate standards promulgated by the U.S. Department of Agriculture, applicable standards prescribed by the laws of the State where the particular product was produced, specifications of any governmental agency, written buyer and seller contract specifications, or any written specifications by an applicant which is approved by the Administrator; Provided, That, if such product is regulated pursuant to the Agricultural Marketing Agreement Act of 1937, as amended (7 U.S.C. 601 et seq.), or the comparable laws of any State, such testing and determination shall be on the basis of the standards, if any, prescribed in, or pursuant to, the marketing order and/or agreement effective thereunder.

Laboratory service shall be performed, insofar as possible, in the order in which applications are made except that precedence may be given to any such applications which are made by the United States (including, but not being limited to, any instrumentality or agency thereof) and to any application for an appeal inspection.

If the scientist determines that it is not possible to accurately analyze or make a laboratory determination of a sample immediately after receipt because standard materials, laboratory equipment and supplies need replacement, or for any other substantial reason, the scientist may postpone laboratory service for such period as may be necessary.

No scientist shall perform a laboratory analysis on any product in which he is directly or indirectly financially interested.