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2026-05-22 · Notice · Federal Register document 2026-10284

Protein Efficiency Ratio Rat Bioassay Studies To Demonstrate That a New Infant Formula Supports the Quality Factor of Sufficient Biological Quality of Protein; Guidance for Industry; Availability

Official abstract: The Food and Drug Administration (FDA or we) is announcing the availability of a guidance entitled "Protein Efficiency Ratio (PER) Rat Bioassay Studies to Demonstrate That a New Infant Formula Supports the Quality Factor of Sufficient Biological Quality of Protein." The guidance provides information for manufacturers and contract laboratories that perform PER studies to assist in designing, conducting, evaluating, and reporting PER studies. The guidance explains "appropriate modifications" of AOAC Official Method 960.48 (the AOAC Method) with the aim of supporting industry in successfully conducting PER studies that demonstrate that a new infant formula meets the quality factor of sufficient biological quality of protein when fed as the sole source of nutrition. The guidance finalizes the approach presented in the draft guidance issued in 2023.