Background: Human milk analyzers are increasingly used to rapidly measure the macronutrient content in breast milk for individual target fortification, to reduce the risk of postnatal growth restriction. However, many milk analyzers are used without calibration, validation or quality assurance. Aims: To investigate measurement quality between different human milk analyzers, to test whether accuracy and precision of devices can be improved by establishing individual calibration curves, and to assess long-term stability of measurements, following good clinical laboratory practice (GCLP). Methods: Sets of identical breast milk samples were sent to 13 participating centres in North America and Europe, for a total of 15 devices. The study included 3 sets of samples: A) initial assessment of the device's performance consisting of 10 calibration samples with random replicates; B) long term stability and quality control consisting of 2 batches of samples to be measured every time before the device is used, over 6 months; C) ring trial consisting of 2 samples to be measured monthly. The devices tested were Unity SpectraStar (n ¼ 5) and MIRIS Human Milk Analyzer (n ¼ 10). Results: There are significant variations in accuracy and precision between different milk analyzers' fat, protein and lactose measurements. However, the accuracy of measurements can be improved by establishing individual correction algorithms. Repeated measurements are more robust when coming from a larger batch volume. Long term stability also varies between devices. Conclusion:The variations in measurements between devices are clinically significant and would impact both daily dietary prescriptions, and the outcomes of clinical studies assessing the effect of targeted adjustment of nutrient intake in preterm babies. This study shows that it is crucial to follow GCLP when using milk analyzers to ensure proper measurement of macronutrients, similar to what is required of other medical devices.

BackgroundInfrared (IR) analysis is an emerging technology that may be a useful tool for milk banks to manage the nutrient variability in donor human milk.ObjectiveTo evaluate the accuracy, reliability, and comparability of commercial infrared analyzers for measuring human milk macronutrients in a milk bank setting.MethodsThree nonprofit milk banks received blinded test kits of human milk that had been assessed using reference methods. Four infrared instruments were used to measure macronutrients as follows: 1 filtered mid-IR, 2 Fourier-transformed full-spectra mid-IR, and 1 near-IR. Twenty-five unique samples were read concurrently for the accuracy arm. An identical sample was read daily for 1 mo for the reliability arm.ResultsValues for R2 describing relationships with reference methods for total fat, crude protein, and lactose, were as follows: filtered mid-IR, 0.98, 0.94, and 0.48; Fourier-transformed full-spectra mid-IR, 0.97, 0.93, and 0.36 for instrument 1 and 0.98, 0.98, and 0.31 for instrument 2; and near-IR 0.93, 0.93, and 0.12. There was no significant difference between instruments for crude protein and total fat measurements. There were significant differences in carbohydrate measurements between instruments. For 1 mo of daily measurements in the reliability arm, CVs for filtered mid-IR were ≤4.6%, for Fourier-transformed full spectra mid-IR were ≤1.7%, and for near-IR were ≤5.1%.ConclusionsInfrared analysis is an accurate and reliable method for measuring crude protein and total fat in a milk bank setting. Carbohydrate measurements are less accurate and are significantly different between instruments, which will likely lead to differences in derived calorie values.

Despite advances in neonatal nutrition, very preterm infants remain at increased risk of extrauterine growth faltering. This prospective study aimed to examine the effect of hindmilk, the milk at the end of a breast expression session, on growth and plasma fatty acids (FAs) of infants born <30 weeks’ gestation who had been on full enteral feeds for ≥2 weeks and had a weight gain of <15 g/kg/day despite optimizing energy and protein intakes. Weight and plasma FAs were assessed before and two weeks after feeding hindmilk. Growth anthropometrics were assessed weekly for four weeks. Paired t-tests and multiple linear regression were used for statistical analyses of data from 34 infants and their 29 mothers. There was a significant increase in weight gain in the two weeks after feeding hindmilk (MD 3.9, 95%CI 1.2–6.5 g/kg/day). Weight Z-scores were larger at two weeks (MD 0.61, 95%CI 0.02–1.20) and onwards. Head circumference Z-scores were larger at three weeks (MD 0.83, 95%CI 0.20–1.47) and onwards. Plasma linoleic acid (LA) and α-linolenic acid (ALA) increased after feeding hindmilk. In conclusion, hindmilk may improve weight and head growth and increase LA and ALA in very preterm infants with suboptimal growth. A large randomized controlled trial is required to examine and validate the potential benefits of hindmilk.

Background: Breastfeeding is the most important factor shaping the infant gut microbiome, providing human milk oligosaccharides (HMOs) that serve as prebiotics for commensal gut bacteria. Donor human milk (DHM) is considered the best alternative when mothers own milk is not available. HMO profiles are highly variable among mothers and there is currently no "matching" process to optimize provision of DHM to recipient infants. The strongest factor influencing HMO composition is maternal secretor status, determined by the expression of a specific gene (α-1, 2-fucosyltransferase-2, FUT2). About 20% of the population are non-secretors and the impact of feeding DHM from secretor donors to infants of non-secretor mothers is not well understood. We aim to explore if matching DHM based on maternal secretor status impacts the development of the gut microbiome in preterm infants. Methods: This is a pilot, randomized, controlled trial of 60 mother-infant dyads, comparing microbial composition of preterm infants (<34 weeks gestation) who receive DHM matched to their mother’s secretor status to infants who receive standard issue (non-matched) DHM. Enrolled mothers will be randomized to either the intervention (n=30) or control group (n=30). Infants of mothers assigned to the intervention group will receive "matched" DHM based on maternal secretor status. Infant fecal samples will be collected weekly until discontinuation of DHM or discharge/transfer from the unit. Samples of mother’s own milk and DHM will also be collected to analyze HMO and nutrient content. Microbial DNA will be analyzed using shallow shotgun sequencing to identify microbial population structures and functional capacity. Microbial composition from intervention and control groups will be compared to determine differences in diversity and taxonomy. The Consolidated Framework for Implementation Research will be used to assess clinical feasibility of the trial in the NICU environment. Discussion: This research could better inform how milk banks and neonatal intensive care units provide DHM to preterm infants. Additionally, it will expand our understanding of the prebiotic effects of HMOs on the infant microbiome and may inform future prebiotic/probiotic supplementation regimens. Trial Registration: Registration on ClinicalTrials.gov was completed on October 17, 2019, and updated on February 11, 2022, with the Identifier: NCT04130165