A systematic review of contaminants in donor human milk

Donor human milk (DHM) from a milk bank is the recommended feeding method for preterm infants when the mother's own milk (MOM) is not available. Despite this recommendation, information on the possible contamination of donor human milk and its impact on infant health outcomes is poorly characterised. The aim of this systematic review is to assess contaminants present in DHM samples that preterm and critically ill infants consume. The data sources used include PubMed, EMBASE, CINAHL and Web of Science. A search of the data sources targeting DHM and its potential contaminants yielded 426 publications. Two reviewers (S. T. and D. L.) conducted title/abstract screening through Covidence software, and predetermined inclusion/exclusion criteria yielded 26 manuscripts. Contaminant types (bacterial, chemical, fungal, viral) and study details (e.g., type of bacteria identified, study setting) were extracted from each included study during full-text review. Primary contaminants in donor human milk included bacterial species and environmental pollutants. We found that bacterial contaminants were identified in 100% of the papers in which bacterial contamination was sought (16 papers) and 61.5% of the full data set (26 papers), with the most frequently identified genera being Staphylococcus (e.g., Staphylococcus aureus and coagulase-negative Staphylococcus) and Bacillus (e.g., Bacillus cereus). Chemical pollutants were discovered in 100% of the papers in which chemical contamination was sought (eight papers) and 30.8% of the full data set (26 papers). The most frequently identified chemical pollutants included perfluoroalkyl substances (six papers), toxic metal (one paper) and caffeine (one paper). Viral and fungal contamination were identified in one paper each. Our results highlight the importance of establishing standardisation in assessing DHM contamination and future studies are needed to clarify the impact of DHM contaminants on health outcomes. This systematic review urges continued research in the field of contaminants and donor human milk (DHM) to delineate the risks and benefits of its use in premature and critically ill infants. Our review reveals traces of chemicals, including PFAs and caffeine, within DHM. Bacteria, viruses and fungi are generally removed from DHM via pasteurisation.image Research regarding chemical contamination in donor human milk (DHM) is limited and needs to be studied further to draw appropriate conclusions on reducing potential risks for infants.Parents/guardians should be educated on the availability of DHM as a supplemental feeding option and made aware of the current research in the field.DHM use requires further standardisation both within the United States and abroad. This standardisation should ensure that risks are not overemphasised and DHM is a cost-effective, accessible resource as a short-term intervention when used appropriately as part of optimal lactation and breastfeeding support.