Re: “The Effect of Processing Donor Milk on Its Nutrient and Energy Content” by Chang et al.

Dear Editor:

We read with great interest the article “The Effect of Processing Donor Milk on Its Nutrient and Energy Content” by Chang et al., ¹ and agree that understanding how human milk is altered through milk banking processes is an important topic for improving preterm infant feeding. The authors report a 20.5% decrease in the fat content of donor milk following Holder Pasteurization, but we are unable to determine whether their methods contributed potential artifacts (related to fat content) because a considerable amount of information was not provided. Specific information missing from the methods that could have significantly influenced the fat content of study samples include the following:

The volume of the original pool, and how it was mixed before drawing the baseline sample.

Chang et al.'s findings of 20.5% fat loss after pasteurization ¹ is well outside the findings reported in a 2016 systematic review of the impact of Holder Pasteurization. ³ Peila et al. reviewed seven studies that measured fat in human milk pre- and post-Holder Pasteurization, and found three studies showing loss in the range of 3.5–8.9%, four studies reporting no significant change, with an overall conclusion that “total lipid content is preserved” by Holder Pasteurization. ³ A more recent study that tested every bottle in a pool (thus eliminating the potential impact of an unequally mixed pool), found no difference in fat content pre- and postpasteurization. ⁴

We urge researchers and Breastfeeding Medicine to provide more detailed methods when publishing studies that measure fat in human milk, given the potential introduction of artifacts related to mixing and sample handling. A detailed methods section is critical for evaluating the strength of the research.