Extensively hydrolysed infant formulas: Need for aligned definition of peptide size characteristics and standardisation of analytical methods.

Letter by Nutten et al. on article by Levin et al. (Levin ME, Blackhurst DM, Kirstein F, Kok D, van der Watt GF, Marais AD. Residual allergenicity of amino acid-based and extensively hydrolysed cow's milk formulas. S Afr Med J 2017;107(9):763-767. S Afr Med J 2017;107(3):258-263. https://doi.org/10.7196/SAMJ.2017.v107i9.12137); and response by Levin et al.