Cal. Food & Agric. Code § 40532
Every certificate which relates to the analysis, classification, condition, grade, or quality of any agricultural product, either raw or processed, and every duly certified copy of such certificate, is prima facie evidence of the truth of the statements which are contained in it, if duly issued in accordance with any of the following:
(c) Under authority of a federal statute.
The presumption established by this section is a presumption affecting the burden of proof, but it does not apply in a criminal action.