The intricate relationship between nutrition and the microbiome in preterm infants is a frontier of neonatal research that continues to unveil profound insights into early-life development and long-term health outcomes. Among the myriad factors influencing this delicate ecosystem, the role of donor human milk and its processing methods has garnered increasing attention. A groundbreaking study published in Pediatric Research by Ocampo-Chih, Hendricks, Weitkamp, and colleagues elucidates how different pasteurization techniques applied to donor human milk impact the gut microbiome of preterm infants, potentially reshaping neonatal nutritional standards and clinical practices globally.
Preterm infants, born before full maturation of their gastrointestinal and immune systems, are especially vulnerable to conditions such as necrotizing enterocolitis (NEC) and sepsis. The establishment of a healthy gut microbiota in these neonates is a critical determinant of risk reduction for such life-threatening conditions. Human milk—from the infant’s own mother or donor milk—is considered the gold standard for feeding preterm infants due to its unique bioactive components, immunological factors, and essential nutrients. However, donor milk must undergo processing to ensure microbiological safety, predominantly through pasteurization, which can inadvertently alter its beneficial properties.
The study at hand delves into two principal pasteurization methods: Holder pasteurization, which involves heating milk to 62.5°C for 30 minutes, and high-temperature short-time (HTST) pasteurization, which rapidly heats milk to 72°C for 15 seconds. While Holder pasteurization has been the traditional and widely implemented standard in milk banks worldwide, emerging evidence suggests that HTST and other novel techniques may better preserve the functional and microbiological integrity of human milk. Yet, their direct effects on the neonatal gut microbiome remained inadequately characterized until now.
By systematically analyzing stool samples from preterm infants fed with milk subjected to either Holder or HTST pasteurization, the research team employed advanced metagenomic sequencing tools to map the complex communities of bacterial taxa colonizing the infants’ gastrointestinal tracts. The investigators discovered striking differences: infants receiving HTST-pasteurized milk showed significantly increased microbial diversity, with a richer abundance of beneficial genera such as Bifidobacterium and Lactobacillus, organisms known to support gut barrier function and modulate immune responses.
These findings highlight that HTST processing preserves more of the milk’s bioactive molecules and endogenous microbiota, elements believed to foster a more favorable microbial colonization. Conversely, the Holder method, although efficacious at eliminating pathogens, may lead to a depletion of these critical components, potentially resulting in a less diverse and more pathogen-prone microbiome. This could, in turn, explain the observed clinical discrepancies in infant outcomes related to feeding regimens that rely exclusively on Holder-pasteurized milk.
The implications transcend microbiology alone. A richer gut microbiome, nurtured by less disruptive milk pasteurization, is intricately tied to improved nutrient absorption, maturation of the immune system, and reduced incidence of inflammatory diseases in preterm infants. Such outcomes align with the overarching goal of neonatal care: to replicate, as closely as possible, the protective environment of the womb, thereby minimizing the vulnerabilities imposed by premature birth.
The research also meticulously measures critical milk components—such as immunoglobulins, enzymes, and growth factors—before and after pasteurization. HTST methodology retains higher levels of these molecules, reinforcing the notion that rapid heating serves as a gentle yet effective microbial inactivation strategy. The preserved biologically active proteins likely act synergistically with the microbial populations to foster an optimal intestinal milieu conducive to health.
Technological advancements in human milk processing thus stand at a pivotal crossroads. The laborious rigor traditionally associated with Holder pasteurization ensured safety but perhaps at the expense of efficacy. The study underscores a paradigm shift advocating for integration of HTST or other innovative methods, potentially transforming standard operating procedures at milk banks and neonatal units worldwide.
Clinicians and neonatologists stand to benefit immensely from these discoveries, as optimized donor milk could serve as a powerful intervention tool. Enhanced microbial diversity in the gut correlates with lower risks of sepsis and NEC, conditions that carry profound morbidity and mortality. Personalized nutrition based on refined milk preparation could ultimately improve neurodevelopmental outcomes through the gut-brain axis, an increasingly validated concept linking early microbiota composition with cognitive trajectories.
Moreover, the researchers propose that future studies should investigate the long-term impacts of these microbial shifts beyond the neonatal period, encompassing infancy and childhood development. Longitudinal tracking of immune markers and growth parameters would provide further clarity on the lasting benefits of improved pasteurization techniques. Such comprehensive approaches will be essential in establishing evidence-based guidelines consolidating the role of donor milk processing in neonatal care.
Critically, the study’s robust methodology, encompassing rigorous sequencing, biochemical assays, and clinical correlation, sets a new benchmark for neonatal nutrition research. Its pioneering approach blends microbiology, biochemistry, and clinical science, reflecting the interdisciplinary nature of tackling prematurity-associated challenges.
The global burden of preterm birth necessitates innovative strategies that extend beyond survival to thriving. Human milk is integral to this mission. Fine-tuning how donor milk is processed could be a simple yet monumental step in safeguarding the health of the most vulnerable infants.
As milk banking infrastructures adapt, incorporating HTST pasteurization protocols may become more feasible with technological advancements lowering operational costs and improving scalability. Widespread adoption can potentially democratize access to superior-quality donor human milk, especially in regions where maternal lactation is compromised or insufficient.
This transformative research thus opens new horizons, uniting science and clinical practice with compassionate care. While ensuring safety remains paramount, optimizing nutritive and immunological properties through refined pasteurization offers an unprecedented opportunity to harness the full potential of donor human milk.
In conclusion, this landmark study by Ocampo-Chih and colleagues represents a critical leap forward in understanding the complex interactions between milk processing methods and the neonatal gut microbiome. By demonstrating that HTST pasteurization better preserves microbial diversity and bioactive constituents compared to the traditional Holder technique, the findings chart a course toward improved neonatal outcomes globally. The compelling evidence calls for reevaluation of current milk banking standards and underscores the importance of continuing research on nutrition-based interventions in preterm infant care.
Subject of Research: The impact of donor human milk pasteurization methods on the gut microbiome composition and diversity in preterm infants.
Article Title: Impact of donor human milk pasteurization methods on the gut microbiome of preterm infants.
Article References:
Ocampo-Chih, C., Hendricks, H., Weitkamp, S. et al. Impact of donor human milk pasteurization methods on the gut microbiome of preterm infants. Pediatr Res (2025). https://doi.org/10.1038/s41390-025-04386-2
