Processing methods of donor human milk evaluated by a blood plasma clotting assay

Donor human milk is the first alternative for preterm infants when mother's own milk is not available. Most available human milk banking guidelines recommend classical holder pasteurization to ensure safety by eliminating potential infectious microorganisms. Processing by heat treatment, however, negatively affects functionality and availability of bioactive components naturally present in human milk. Here we compared the effect of five different processing methods on the ability of human milk to induce blood plasma clotting, which was recently described as a bioactive function present in human milk. From thirty lactating women, milk samples were collected, and all milk samples were subjected to holder pasteurization (30 min at 62.5 °C), high-temperature-short-time pasteurization (15 s at 72 °C), high-pressure processing (5 min at 500 MPa), ultraviolet-C irradiation (4863 J/L), or thermo-ultrasonication (6 min at 60 W, at 40 °C). All methods significantly reduced the ability of milk to trigger blood plasma clotting compared to untreated milk, but ultraviolet-C irradiation and high-pressure processing were best at preserving this activity. Taken together, measuring the ability of milk to induce blood plasma clotting may offer a new tool to monitor the effect of human milk processing. •Holder pasteurization reduces the ability of donor human milk to trigger blood plasma clotting.•Blood plasma clotting may be a new bioassay to monitor the effect of donor human milk processing methods.•This bioassay shows the clotting activity is best preserved by high-pressure processing and ultraviolet-C irradiation.