New FDA Guidance on Infant Formula Protein Efficiency Ratio (PER) Studies

The FDA has issued final guidance for industry on Protein Efficiency Ratio rat bioassay studies used to demonstrate that new infant formulas meet the required “quality factor of sufficient biological quality of protein.” The guidance outlines the agency’s current recommendations for infant formula manufacturers and testing laboratories on the design, conduct, evaluation and reporting of PER studies, which the agency said are used to assure the quality of protein in infant formula. The guidance explains how manufacturers can adapt the AOAC Official Method 960.48 PER rat bioassay to account for the unique nutritional composition of infant formula products. The FDA said in a Federal Register notice scheduled for publication tomorrow that the guidance was developed after the agency “found that industry is experiencing difficulties in consistently meeting” the existing regulatory requirements for demonstrating protein quality. The final document also incorporates changes made in response to comments submitted on the 2023 draft guidance, including recommendations related to diet matching flexibility and nutrient composition adjustments.