Inoculation of Mother’s Own Milk Could Personalize Microbiological, Metataxonomic and Peptidomic Profile of Pasteurized Donor Human Milk Used for Feeding Preterm Infants

Abstract Background Human milk is a vehicle of bioactive compounds and beneficial bacteria which promote the establishment of a healthy gut microbiome of newborns, especially of preterm infants. Pasteurized donor human milk (PDHM) is the second-best option when preterm mother’s own milk is unavailable. Since pasteurization affect the quality of donor milk, the effect on bacterial growth, human milk microbiota diversity and proteolytic phenomena in PDHM inoculated with different preterm milk samples, was evaluated. Methods Ten preterm milk samples was used to perform inoculation of PDHM at 10% v/v. Microbiological, metataxonomic and peptidomic analysis, on preterm milk samples at the baseline (T0) and PDHM and inoculated milk (IM) samples at T0, after 2h (T1) and 4h (T2) of incubation at 37°C, were conducted. Results IM samples at T2 showed a Total Bacterial Count not significantly different (p > 0.01) compared to preterm milk samples. Lactic acid bacteria (LAB) level was restored in all IM at T2. After inoculation, metataxonomic analysis showed that Proteobacteria remained the predominant phylum while Firmicutes moved from 3% at T1 to 9.4% at T2 in IM samples. Peptidomic profile of IM resembled that of PDHM incubated for the same time in terms of number and type of peptides. Conclusion The study demonstrated that inoculation with fresh mother’s own milk could restore bacterial growth and personalize human milk microbiome in PDHM. This effect could be beneficial thanks to the presence of maternal probiotic bacteria which make PDHM more similar to mother’s own milk.