Guidelines for the establishment and operation of a donor human milk bank

Review of current best practices for human milk banking

Mother's/parent milk is the optimal way to feed infants and when unavailable, supplemental donor human milk is preferred. A safe supply of donor human milk should be available for all low birthweight infants for whom it has been shown to reduce morbidity. Human milk banking has been in existence for more than a century, although largely shut down during the 1980s, primarily due to fears of human immunodeficiency virus transmission. With renewed security in milk banking, has come an exponential growth in human donor milk use. Guidelines for milk banking have been published in many countries including Australia, France, India, Italy, Spain, Switzerland, the United Kingdom and the nonprofit organization PATH. The European Milk Bank Association and the Human Milk Banking Association of North America have also published recommendations for milk banks throughout Europe and North America, respectively. Although there is variability among these guidelines, there is general consensus on quality control measures required to provide a supply of safe donor milk. These measures include effective donor screening, safe collection, transport and storage of milk, standardized pasteurization and bacteriological testing. Operational considerations are also critical, such as appropriate training for staff, equipment maintenance and cleaning, protocol and record keeping and inspection and accreditation. Clearly delineating these key quality control measures provides an excellent foundation for establishing international guidelines. Acceptable modifications must be established for low- and middle-income countries that do not have sufficient resources; overly burdensome guidelines may make establishing a milk bank unnecessarily prohibitive. This review presents a summary of current best practices for human milk banking.

Investigating Milk Fat Globule Structure, Size, and Functionality after Thermal Processing and Homogenization of Human Milk

Human milk provides bioactive compounds such as milk fat globules (MFGs), which promote brain development, modulate the immune system, and hold antimicrobial properties. To ensure microbiological safety, donor milk banks apply heat treatments. This study compares the effects of heat treatments and homogenization on MFG's physicochemical properties, bioactivity, and bioavailability. Vat pasteurization (Vat-PT), retort (RTR), and ultra-high temperature (UHT) were performed with or without homogenization. UHT, RTR, and homogenization increased the colloidal dispersion of globules, as indicated by increased zeta potential. The RTR treatment completely inactivated xanthine oxidase activity (a marker of MFG bioactivity), whereas UHT reduced its activity by 93%. Interestingly, Vat-PT resulted in less damage, with 28% activity retention. Sialic acid, an important compound for brain health, was unaffected by processing. Importantly, homogenization increased the in vitro lipolysis of MFG, suggesting that this treatment could increase the digestibility of MFG. In terms of color, homogenization led to higher L* values, indicating increased whiteness due to finer dispersion of the fat and casein micelles (and thus greater light scattering), whereas UHT and RTR increased b* values associated with Maillard reactions. This study highlights the nuanced effects of processing conditions on MFG properties, emphasizing the retention of native characteristics in Vat-PT-treated human milk.

Label-Free quantitation of milk oligosaccharides from different mammal species and heat treatment influence

Milk oligosaccharides (MOs) exhibit significant variations in concentrations and patterns among different species. However, there is limited knowledge about milk oligosaccharides in domestic animals and the impact of heat treatment on them. Here, we developed an LC-ESI-MS/MS method to analyze 11 milk oligosaccharides in 7 distinct species simultaneously. The results showed that human milk presented a completely different composition pattern of milk oligosaccharides from animals. In detail, animal milk predominantly contained sialylated oligosaccharides, and human milk had high levels of fucosylated neutral oligosaccharides. Notably, sheep milk exhibited similarities to human milk in terms of oligosaccharides composition. Then, the milk samples from dairy cows were treated with two common industrial heat treatments. We found that 65 °C treatment had no significant effect on the concentration of milk oligosaccharides, whereas 135 °C heating was associated with their decline, suggesting that high temperatures should be avoided in the processing of oligosaccharides supplemented/enriched products.

Microbiological Screening of Donor Human Milk

Mother's own milk is recognized as the optimal feeding not only for term but also for preterm infants. In addition to risk reduction for sepsis, necrotizing enterocolitis, bronchopulmonary dysplasia, and retinopathy of prematurity in the early infancy, feeding preterm infants with mother's own milk is also associated with a better neurodevelopmental outcome; lower rates of otitis media, gastroenteritis, and respiratory infections; and a reduced risk of cardiovascular disease, obesity, and diabetes later in life. Donor human milk is the best alternative if mother's own milk is not available or with short supply. There is growing evidence that the benefits of human milk are mediated by the human milk microbiota and by human milk oligosaccharides through their influence on the infant's gut microbiota. Unfortunately, although human milk contains beneficial bacteria, it may also contain pathogenic bacteria. The antimicrobial properties of human milk protect those infants fed with their own mother's raw milk. In donor human milk, however, the antimicrobial activity is diminished due to storage and in particular by pasteurization, hereby lowering the resistance against bacterial infections. Subsequently, microbiological screening of donor human milk might enhance its safety for preterm infants. Up to date, a consensus on recommendations for the microbiological testing of donor human milk is lacking. Existing local and national guidelines for the microbiological screening vary significantly in terms of timing and frequency of testing as well as their specific acceptance and discard criteria. We reviewed the literature about microbiological testing of donor human milk to provide evidence-based recommendations for donor human milk.

A descriptive analysis of human milk dispensed by the Leipzig Donor Human Milk Bank for neonates between 2012 and 2019

Background

Human milk banking has become an important aspect of Nutritional medicine. It is not just about the provision of mother's own milk (MOM) or donor human milk (DHM) in the hospital, but also a strategy to encourage breastfeeding in the clinical setting and beyond.

Objective

To describe the feeding patterns of hospitalised infants including human milk dispensed by the Leipzig Donor Human Milk Bank (LMB).

Design

A descriptive analysis of daily data on milk feeds dispensed by LMB for hospitalised infants distinguishing between MOM or DHM, either fresh or frozen, and raw/pasteurised milk from 2012-2019.

Results

We included 2,562 infants with median hospitalisation of 23 days, for whom human milk was dispensed on median 76% of those days and other nutrition on the remaining days. Raw MOM and raw DHM comprised 52% and 8% of the dispensed milk, respectively. Dispensing exclusive DHM instead of MOM for at least one full day was required for 55% of the infants, mostly at the beginning but also later during hospitalisation. Exclusive raw DHM was dispensed on at least 1 day for 37% of the infants, in different birthweight strata <1,000 g: 10%, 1,000-1500 g: 11%, 1,500-2500 g: 13% and > 2,500 g: 3%. At discharge, MOM was dispensed for more than 60% of the infants.

Conclusion

During an infant's hospital stay, LMB dispenses various human milk feeds with interspersed DHM resulting in complex intra-individual and time-variant feeding patterns. LMB dispenses raw MOM and especially raw DHM with the intention to retain the properties of human milk unlike a diet containing pasteurised DHM and/or formula. Although raw DHM comprises a small percentage of all dispensed milk, raw DHM is dispensed for a substantial portion of infants. Our results document that dispensing raw DHM, is possible in routine settings.

High-Temperature Pasteurization Used at Donor Breast Milk Banks Reduces Melatonin Levels in Breast Milk

Background and Objective: Donor human milk banks are used when breast milk directly from mothers is unavailable or insufficient. Breast milk contains melatonin, which exhibits a 24-hour pattern. Melatonin promotes sleep onset and is barely detected in daytime milk but rises in the evening and peaks early in the morning. Melatonin supports the development of an infant's own circadian rhythm and is important for neurodevelopment. Currently, donor banks pasteurize breast milk using a Holder Pasteurization (HoP) technique where breast milk is treated at a high temperature (+62°) for 30 minutes before cooling to eliminate any pathogens before it is given to infants. It is not known how the pasteurization process affects the melatonin levels in breast milk. The aim of this study was to investigate whether the pasteurization process reduces melatonin levels in breast milk. Materials and Methods: Ten night-time breast milk samples were collected and each divided into two groups; one group remained unpasteurized and the other group was pasteurized using the HoP technique. Results: Melatonin levels between the unpasteurized and pasteurized groups were compared. Results showed that there was a significant reduction after pasteurization (mean ± standard deviation = 51.92 pg/mL ± 19.54 versus 39.66 pg/mL ± 13.05, p = 0.01). Conclusions: It is important to understand that pasteurization can reduce melatonin levels in breast milk because this hormone is considered important to support the neurodevelopment of infants, especially those born preterm. Further focus on the effect of pasteurization techniques on melatonin in donor breast milk is warranted.

Pooling Strategies to Modify Macronutrient Content of Pasteurized Donor Human Milk

Background: Donor human milk (DHM) is the recommended feeding for preterm infants when mother's own milk is unavailable or insufficient. DHM macronutrient's variability may have significant implications on preterm growth. Different pooling strategies could be used to improve the macronutrient content, facilitating the achievement of nutritional requirements of preterm. Objective: The aim was to compare the impact of random pooling (RP) and target pooling (TP) strategies on the macronutrient content of DHM and to identify which RP practice allows the achievement of a macronutrient composition as similar as possible to that achievable with TP. Methods: The macronutrient content of 1,169 single-donor pools was analyzed, and a TP strategy combining 2,3,4, or 5 single-donor pools was adopted. On the bases of single-donor pools' analyses, a simulation of 10,000 randomly selected pools for each configuration of donor considered and for different milk volume proportions was performed. Results: Regardless of the type of strategy and milk volume, as the number of donor per pool increases, the percentage of pools with a macronutrient content equal or higher than the reference values for human milk increases. Conclusion: When a TP strategy is not feasible, a RP strategy combining at least five donors should be performed to obtain a better macronutrient content of DHM.

How Can We Prevent Mother-to-Child Transmission of HTLV-1?

The perception of human T-cell leukemia virus type 1 (HTlV-1) infection as a "silent disease" has recently given way to concern that its presence may be having a variety of effects. HTLV-1 is known to cause adult T-cell leukemia (ATL), an aggressive cancer of peripheral CD4 T cells; however, it is also responsible for HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Most patients develop ATL as a result of HTLV-1 mother-to-child transmission. The primary route of mother-to-child transmission is through the mother's milk. In the absence of effective drug therapy, total artificial nutrition such as exclusive formula feeding is a reliable means of preventing mother-to-child transmission after birth, except for a small percentage of prenatal infections. A recent study found that the rate of mother-to-child transmission with short-term breastfeeding (within 90 days) did not exceed that of total artificial nutrition. Because these preventive measures are in exchange for the benefits of breastfeeding, clinical applications of antiretroviral drugs and immunotherapy with vaccines and neutralizing antibodies are urgently needed.

Supplementation of Mother's Own Milk with Preterm Donor Human Milk: Impact on Protein Intake and Growth in Very Low Birth Weight Infants-A Randomized Controlled Study

This randomized study investigates whether feeding very low birth weight (VLBW) infants with mother's own milk (MOM) supplemented with either preterm (PDM) or term donor milk (TDM), when MOM is insufficient, has a positive impact on infants' protein intake and growth. A hundred and twenty VLBW infants were randomized into two groups. Group A (43 infants) received MOM supplemented with PDM, whereas Group B (77 infants) was fed with MOM supplemented with TDM, for the first three weeks of life (donor milk period). Breast milk fortifier was added when milk feeds exceeded 50 mL/Kg/day. After the donor milk period, both groups were fed with formula when MOM was not available or the milk bank was unable to provide TDM. Protein intake was higher in Group A than in Group B at initiation of milk fortification (p = 0.006), as well as during the 3-week donor milk period (p = 0.023) and throughout hospitalization (p = 0.014). Moreover, Group A presented higher Δz-score for body weight (p = 0.019) and head circumference (p = 0.001) from birth to the end of donor milk period, and higher mean body weight at discharge (p = 0.047) compared to Group B. In conclusion, when donor milk is required, PDM positively impacts protein intake and growth in VLBW infants (NCT05675397).

Breastfeeding and human milk bank in a neonatal intensive care unit: impact of the COVID-19 pandemic in an Italian cohort of very low birth weight infants

BACKGROUND

Parental stress in neonatal intensive care units (NICU) is well known, as is the stress induced by the COVID-19 pandemic. This combination might increase stress to the extent of affecting the availability of maternal expressed milk and the success of establishing breastfeeding. This is particularly relevant in very preterm infants.

METHODS

We conducted a single-centre retrospective analysis in two cohorts of very low birth weight infants born in a hospital in Italy. Babies born before the pandemic (September 2017 - December 2019) (n = 101) and during the pandemic (March 2020 - December 2021) (n = 67) were included in the analysis. We compared the rate of babies fed with maternal milk (both expressed and / or donated) at the achievement of full enteral feeding and the rate of those exclusively breastfed at discharge in the two groups. Then, we analysed the impact of donated human milk availability on infant formula use. We also compared mother's need for psychological support during NICU stay and the duration of psychological follow-up after discharge.

RESULTS

In our NICU the availability of expressed maternal milk significantly decreased during the COVID-19 pandemic (86.1% before the pandemic vs 44.8% during the pandemic, p < 0.001) at the time of full enteral feeding achievement. Thanks to the availability of donated human milk, the rate of formula-fed babies remained almost unchanged (13.9% vs 14.9%). At discharge, the rate of breastfeeding was similar (73.3% vs 72.7%). The maternal need for psychological support was significantly higher during the pandemic (33% vs 64%, p < 0.001), as well as the duration of follow-up > 6 months (1% vs 15%, p < 0.001). No differences in the main clinical outcomes were found.

CONCLUSION

Pandemic-induced stress had a significant impact on the availability of expressed maternal milk in NICU. However, the presence of human donated milk was fundamental in preventing increased use of infant formula during NICU stays. This underlines how strategies to implement the widespread establishment of donor milk banks on a national level are warranted. Further research is desirable to optimise the use of donated human milk banks during emergency situations.

How much does a liter of donor human milk cost? Cost analysis of operating a human milk bank in Italy

BACKGROUND

To date, 40 Human Milk Banks (HMB) have been established in Italy; however, recent cost analysis data for operating an HMB in Italy are not available in the literature.

METHODS

This study was a cross-sectional study performed at "Bambino Gesù" Children's Hospital in Rome, Italy in 2019. We assessed the one-year operational costs and, the per liter unit costs at our HMB.

RESULTS

During the 2019 year we collected 771 l of human milk supplied by 128 donors. The total cost was € 178,287.00 and the average cost was € 231.00 per liter. € 188,716.00 would have been spent had the maximum capacity for 904 l been reached. We found a significant difference (€ 231.00 vs € 209.00 per liter, p = 0.016) comparing the cost for collected liters in the year 2019 and the cost for the maximum capacity of the bank for that year of activity. Analyzing each cost item that determines the charge of donor human milk (DHM), the highest costs are the salaries of medical and paramedical staff, and then the costs related to transporting. If the HMB works at maximum capacity and manages a greater number of liters of milk, this can represent an important saving. Conversely, the price of consumables is modest (i.e., the price of a single-use kit for breast pumps was € 0.22 per unit).

CONCLUSION

The costs for a liter of DHM are quite high, but they must be related to the benefits, especially for preterm infants. Comparing the cost for collected liters in 2019 and the costs for the 2019 maximum capacity of the HMB, we calculated how much fixed costs of collection and distribution of DHM can be reduced, by increasing the volume of milk collected. To the best of our knowledge, this is the first complete cost analysis for an Italian Milk Bank. A thorough analysis could help to abate fixed costs and reduce the cost of a liter of DHM. The centralization of DHM can allow savings, rather than creating small HMBs scattered throughout the territory that would operate with lower milk volumes.

Compliance in handling of donated raw breast milk to human milk banks regarding microbiological quality

Abstract Objectives: microbiological quality of raw human milk (HM) from donors at the HMB (Human Milk Bank) of Santa Casa de Misericórdia de Ouro Preto was evaluated. Methods: the microbiological quality of milk from each of 10 donors in triplicate (30 samples) was evaluated by enumeration of Staphylococcus aureus and total aerobic mesophiles (surface plating) and total and thermotolerant coliforms (Most Probable Number - MPN). A questionnaire and a checklist were applied after the end of sample collection to verify the compliance of milk extraction and storage procedures by the donors. Results: inadequacies in the procedures for expression and storage of donated HM were observed. The presence of all microorganisms studied were verified in the milk of all donors, and in some cases exceeded the safety limits. The checklist indicated that some necessary hygienic-sanitary procedures were not carefully performed, making it important to properly guide the donors. Conclusions: this study points to an unfavorable scenario for the safety and quality of donated HM, and it is important to encourage further studies to be conducted so that the Brazilian network of HMB adopts stricter criteria for instructions on procedures and support for HM donors.

A Pilot Study on Donor Human Milk Microbiota: A Comparison with Preterm Human Milk Microbiota and the Effect of Pasteurization

Human milk (HM) is the best feeding option for preterm infants; however, when mother’s own milk (MOM) is not available, pasteurized donor human milk (DHM) is the best alternative. In this study, we profiled DHM microbiota (19 samples) using 16S rRNA amplicon sequencing and compared its compositional features with the MOM microbiota (14 samples) from mothers who delivered prematurely (PT-MOM). As a secondary study aim, we assessed the specific effect of pasteurization on the characteristics of the DHM microbiota. DHM showed significantly higher alpha diversity and significant segregation from PT-MOM. Compositionally, the PT-MOM microbiota had a significantly higher proportion of Staphylococcus than DHM, with Streptococcus tending to be and Pseudomonas being significantly overrepresented in DHM compared with the PT-MOM samples. Furthermore, pasteurization affected the HM microbiota structure, with a trend towards greater biodiversity and some compositional differences following pasteurization. This pilot study provided further evidence on the HM microbial ecosystem, demonstrating that the DHM microbiota differs from the PT-MOM microbiota, possibly due to inherent differences between HM donors and mothers delivering prematurely, and that pasteurization per se impacts the HM microbiota. Knowledge about HM microbiota needs to be acquired by investigating the effect of DHM processing to develop strategies aimed at improving DHM quality while guaranteeing its microbiological safety.

Receiving screened donor human milk for their infant supports parental wellbeing: a mixed-methods study

BACKGROUND

Access to donor human milk (DHM) has primarily been based on the health and development outcomes of premature infants but there has been little examination of the broader impact of an infant receiving it upon parental mental health. Breastfeeding and mental health are closely tied with women who experience breastfeeding difficulties or are unable to meet their own breastfeeding goals often experiencing feelings of guilt, sadness and anger, alongside an increased risk of postnatal depression. The aim of the current study was to explore how experience of receiving DHM for their baby affected the wellbeing of parents.

METHODS

UK parents of infants aged 0 - 12 months who had received screened DHM from a milk bank (typically on the neonatal unit or in some cases in the community) completed an online questionnaire exploring their experiences. The questionnaire included Likert scale items examining perceived impact upon infant health, own wellbeing and family functioning alongside open-ended questions exploring perceptions of how receiving DHM affected wellbeing.

RESULTS

Almost all of the 107 participants (women = 102) agreed that receiving DHM had a positive impact upon infant health and development, their own mental and physical health, and their family's wellbeing. Parents felt relieved that their infant was receiving DHM for health reasons but also due to the experience of being listened to, supported and having their infant feeding decisions facilitated. Receiving DHM helped mothers to process some of their emotions at not being able to breastfeed, in part because knowing their baby was being fed gave them the space to focus on recovery and bonding with their baby. Some parents did experience challenges, feeling guilty at receiving DHM, insecure that another woman was able to feed their baby when they could not, or negative reactions from family. Although the impact of receiving DHM upon breastfeeding was not measured, some women who were working to build their own milk supply noted that it helped motivate them to continue.

CONCLUSIONS

DHM may play an important role not only in protecting infant health and development but in supporting the mental health and wellbeing of mothers for whom their infant receiving human milk is important.

Human milk glycosaminoglycans inhibit cytomegalovirus and respiratory syncytial virus infectivity by impairing cell binding

BACKGROUND

The antiviral role of glycosaminoglycans in human milk (HM-GAGs) has been poorly investigated. They are highly sulfated polysaccharides, which were proposed to act as decoy receptors according to their structure. The aim of this study is to evaluate the antiviral potential and the mechanism of action of total and individual HM-GAGs against three pediatric clinically relevant viruses: respiratory syncytial virus (RSV), cytomegalovirus (HCMV), and rotavirus.

METHODS

HM-GAGs were isolated from HM and a library of individual GAGs, structurally related to HM-GAGs, was prepared. The antiviral activity of HM-GAGs and the impact of thermal treatment were investigated in vitro by specific antiviral assays.

RESULTS

We demonstrated that HM-GAGs are endowed with anti-HCMV and anti-RSV activity and that they act by altering virus attachment to cell. We clarified the contribution of individual HM-GAGs, showing a specific structure-related activity. We did not observe any alteration of HM-GAG antiviral activity after thermal treatment.

CONCLUSIONS

We showed that HM-GAGs contribute to the overall antiviral activity of HM, likely exerting a synergic action with other HM antiviral agents. HM-GAGs can now be added to the list of endogenous factors that may reduce breast-milk-acquired HCMV symptomatic infections and protecting infants from respiratory tract infections by RSV.

IMPACT

HM-GAGs have been poorly investigated for their antiviral action so far. We demonstrated that HM-GAGs are endowed with significant anti-HCMV and anti-RSV activity and that they are able to alter virus binding to the cell. The contribution of individual HM-GAGs is mainly exerted by the FMHep and is not based on a simple charge interaction between the virus and sulfate groups but involves a specific GAG structural configuration. Our results contribute to identifying the multiple factors synergically acting in mediating HM antiviral properties and to clarifying their specific mechanism of action.

Neither Incretin or Amino Acid Responses, nor Casein Content, Account for the Equal Insulin Response Following Iso-Lactose Loads of Natural Human and Cow Milk in Healthy Young Adults

Human milk contains <50% less protein (casein) than cow milk, but is equally effective in insulin secretion despite lower postingestion hyperaminoacidemia. Such potency of human milk might be modulated either by incretins (glucagon-like polypeptide-1,GLP-1); glucose-inhibitory-polypeptide, GIP), and/or by milk casein content. Healthy volunteers of both sexes were fed iso-lactose loads of two low-protein milks, i.e., human [Hum] (n = 8) and casein-deprived cow milk (Cow [↓Cas]) (n = 10), as well as loads of two high-protein milks, i.e., cow (n = 7), and casein-added human-milk (Hum [↑Cas]) (n = 7). Plasma glucose, insulin, C-peptide, incretins and amino acid concentrations were measured for 240′. All milks induced the same transient hyperglycemia. The early [20′−30′] insulin and C-peptide responses were comparable among all milk types apart from the low-protein (Cow [↓Cas]) milk, where they were reduced by <50% (p < 0.05 vs. others). When comparing the two high-protein milks, GLP-1 and GIP [5’−20’] responses with the (Hum [↑Cas]) milk were lower (by ≈2−3 fold, p < 0.007 and p < 0.03 respectively) than those with cow milk, whereas incretin secretion was substantially similar. Plasma amino acid increments largely reflected the milk protein content. Thus, neither casein milk content, nor incretin or amino acid concentrations, can account for the specific potency of human milk on insulin secretion, which remains as yet unresolved.

Testing the effects of processing on donor human Milk: Analytical methods

Holder pasteurization is the current recommended method for donor human milk treatment. This method effectively eliminates most life-threatening contaminants in donor milk, but it also greatly reduces some of its biological properties. Consequently, there is a growing interest for developing novel processing methods that can ensure both microbial inactivation and a higher retention of the functional components of donor milk. Our aim was to offer a comprehensive overview of the analytical techniques available for the evaluation of such methods. To suggest an efficient workflow for the analysis of processed donor milk, a safety analytical panel as well as a nutritional value and functionality analytical panel are discussed, together with the principles, benefits, and drawbacks of the available techniques. Concluding on the suitability of a novel method requires a multifactorial approach which can be achieved by a combination of analytical targets and by using complementary assays to cross-validate the obtained results.

Effects of High-Pressure Processing, UV-C Irradiation and Thermoultrasonication on Donor Human Milk Safety and Quality

Holder pasteurization (HoP) is the current recommended treatment for donor human milk. Although this method inactivates microbial contaminants, it also negatively affects various milk components. High-pressure processing (HPP, 400, 500, and 600 MPa), ultraviolet-C irradiation (UV-C, 2,430, 3,645, and 4,863 J/L) and thermoultrasonication (TUS, 1,080 and 1,620 kJ/L) were investigated as alternatives to thermal pasteurization (HoP). We assessed the effects of these methods on microbiological safety, and on concentration and functionality of immunoglobulin A, lactoferrin, lysozyme and bile salt-stimulated lipase, with LC-MS/MS-based proteomics and activity assays. HoP, HPP, TUS, and UV-C at 4863 J/L, achieved >5-log10 microbial reduction. Native protein levels and functionality showed the highest reduction following HoP, while no significant reduction was found after less intense HPP and all UV-C treatments. Immunoglobulin A, lactoferrin, and lysozyme contents were also preserved after low intensity TUS, but bile salt-stimulated lipase activity was significantly reduced. This study demonstrated that HPP and UV-C may be considered as suitable alternatives to HoP, since they were able to ensure sufficient microbial inactivation while at the same time better preserving the bioactive components of donor human milk. In summary, our results provide valuable insights regarding the evaluation and selection of suitable processing methods for donor human milk treatment, which may replace HoP in the future.

The Influence of Holder Pasteurization on the Diversity of the Human Milk Bacterial Microbiota Using High-Throughput DNA Sequencing

BACKGROUND

Human milk is the best food for infants; however, when breastfeeding is not possible, pasteurized milk from human milk banks is the best alternative. Little has been reported about variations in the bacterial microbiota composition of human milk after pasteurization.

RESEARCH AIM

To characterize and compare the bacterial microbiota composition and diversity within human milk among Mexican mothers before and after the Holder pasteurization process.

METHODS

A cross-sectional, observational, and comparative design was used. The effect of the pasteurization process on the bacterial composition and diversity of human milk samples of donors (N = 42) from a public milk bank was assessed before and after pasteurization by high throughput deoxyribonucleic acid sequencing of V3-16S rRNA gene libraries. Sequencing data were examined using the Quantitative Insights into Microbial Ecology software and Phyloseq in R environment.

RESULTS

A varied community of bacteria was found in both raw and pasteurized human milk. The bacterial diversity of the milk samples was increased by the pasteurization, where some thermoduric bacteria of the phyla Proteobacteria, Firmicutes, and Actinobacteria were more abundant. The source tracker analysis indicated that at most 1.0% of bacteria may have come from another source, showing the safety of the process used to treat milk samples.

CONCLUSION

The pasteurization process increased the bacterial diversity. We selected taxa capable of surviving the process, which could proliferate after the treatment without being a risk for infants.

NMR Metabonomic Profile of Preterm Human Milk in the First Month of Lactation: From Extreme to Moderate Prematurity

Understanding the composition of human milk (HM) can provide important insights into the links between infant nutrition, health, and development. In the present work, we have longitudinally investigated the metabolome of milk from 36 women delivering preterm at different gestational ages (GA): extremely (<28 weeks GA), very (29–31 weeks GA) or moderate (32–34 weeks GA) premature. Milk samples were collected at three lactation stages: colostrum (3–6 days post-partum), transitional milk (7–15 days post-partum) and mature milk (16–26 days post-partum). Multivariate and univariate statistical data analyses were performed on the ¹H NMR metabolic profiles of specimens in relation to the degree of prematurity and lactation stage. We observed a high impact of both the mother’s phenotype and lactation time on HM metabolome composition. Furthermore, statistically significant differences, although weak, were observed in terms of GA when comparing extremely and moderately preterm milk. Overall, our study provides new insights into preterm HM metabolome composition that may help to optimize feeding of preterm newborns, and thus improve the postnatal growth and later health outcomes of these fragile patients.

The hidden universe of human milk microbiome: origin, composition, determinants, role, and future perspectives

Although traditionally considered sterile, human milk is currently recognized as an alive ecosystem that harbors not only bacteria, but also viruses, fungi and yeasts, and minor genera, collectively known as the human milk microbiome (HMM). The seeding of HMM is a complex phenomenon whose dynamics are still a matter of research. Many factors contribute to its determination, both maternal, neonatal, environmental, and related to human milk itself. The transmission of microorganisms to the infant through breastfeeding may impact its present and future health, mainly shaping the GI tract microbiome and immune system. The existence and persistence of HMM as a conserved feature among different species may also have an evolutionary meaning, which will become apparent only in evolutionary times.

CONCLUSION

The complexities of HMM warrant further research in order to deepen our knowledge on its origin, determinants, and impact on infants' health. The practical and translational implications of research on HMM (e.g., reconstitution of donor human milk through inoculation of infant's own mother milk, modulation of HMM through maternal dietary supplementation) should not be overlooked.

WHAT IS KNOWN

• Human milk harbors a wide variety of microorganisms, ranging from bacteria to viruses, fungi and yeasts, and minor genera. • Human milk microbiome is shaped over time by many factors: maternal, neonatal, environmental, and related to human milk itself. • The transmission of microorganisms through breastfeeding may impact the infant's present and future health.

WHAT IS NEW

• We provide an overview on human milk microbiome, hopefully encouraging physicians to consider it among the other better-known breastfeeding benefits. • Further studies, with standardized and rigorous study designs to enhance accuracy and reproducibility of the results, are needed to deepen our knowledge of the human milk microbiota and its role in newborn and infant's health.

The Effect of Pasteurization on the Antioxidant Properties of Human Milk: A Literature Review

High rates of oxidative stress are common in preterm born infants and have short- and long-term consequences. The antioxidant properties of human milk limits the consequences of excessive oxidative damage. However, as the mother's own milk it is not always available, donor milk may be provided as the best alternative. Donor milk needs to be pasteurized before use to ensure safety. Although pasteurization is necessary for safety reasons, it may affect the activity and concentration of several biological factors, including antioxidants. This literature review describes the effect of different pasteurization methods on antioxidant properties of human milk and aims to provide evidence to guide donor milk banks in choosing the best pasteurization method from an antioxidant perspective. The current literature suggests that Holder pasteurization reduces the antioxidant properties of human milk. Alternative pasteurization methods seem promising as less reduction is observed in several studies.

Shrimp ferritin greatly improves the physical and chemical stability of astaxanthin

The low stability of trans-astaxanthin (AX) not only limits its applications as a functional factor in food systems, but also affects the sensor quality of most shrimp products. Therefore, it is important to find an easy, effective way to improve the physical and chemical stability of AX. In this study, by taking advantage of the co-existence of AX and shrimp ferritin (Marsupenaeus japonicus ferritin, MjF), we investigated the interaction of AX with MjF. Results showed that AX molecules are able to bind on the outer surface of MjF to form complexes, and quantitative analyses demonstrated that one ferritin molecule is bound to ∼48 AX molecules. Consequently, such binding not only greatly enhances the water solubility, thermal stability, and photo stability of AX, but also protects AX from Fe²⁺ -induced oxidative damage, as compared to free AX. Thus, MjF could be used as a protective molecule to improve the physical and chemical stability of AX. PRACTICAL APPLICATION: Our study opens up a new avenue for improving the physicochemical properties of bioactive molecules by interacting with protein, and shrimp ferritin could be explored as a protective system for the bioactive molecules.

Inoculation of mother's own milk could personalize pasteurized donor human milk used for feeding preterm infants

BACKGROUND

Human milk is a vehicle for 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 microbiological quality of donor milk, PDHM was inoculated with different preterm milk samples and then incubated, in order to evaluate the effect in terms of bacterial growth, human milk microbiome and proteolytic phenomena.

METHODS

In an in-vitro study PDHM was inoculated at 10% v/v using ten preterm milk samples. Microbiological, metataxonomic and peptidomic analyses, on preterm milk samples at the baseline (T0), on PDHM and on inoculated milk (IM) samples at T0, after 2 h (T1) and 4 h (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. At T2 lactic acid bacteria level was restored in all IM. After inoculation, metataxonomic analysis in IM samples showed that Proteobacteria remained the predominant phylum while Firmicutes moved from 3% at T1 to 9.4% at T2. 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 of PDHM with mother's own milk could restore bacterial growth and personalize human milk microbiome in PDHM. This effect could be beneficial because of the presence of maternal probiotic bacteria which make PDHM more similar to mother's own milk.

The Effects of Thermal Pasteurisation, Freeze-Drying, and Gamma-Irradiation on the Antibacterial Properties of Donor Human Milk

The most common pasteurisation method used by human milk banks is Holder pasteurisation. This involves thermal processing, which can denature important proteins and can potentially reduce the natural antimicrobial properties found in human milk. This study assesses the application of a hybrid method comprised of freeze-drying followed by low-dose gamma-irradiation for nonthermal donor human milk pasteurisation. Freeze-drying donor human milk followed by gamma-irradiation at 2 kGy was as efficient as Holder pasteurisation in the reduction of bacterial inoculants of Staphylococcus aureus (10⁶ cfu/mL) and Salmonella typhimurium (10⁶ cfu/mL) in growth inhibition assays. These assays also demonstrated that human milk naturally inhibits the growth of bacterial inoculants S. aureus, S. typhimurium, and Escherichia coli. Freeze drying (without gamma-irradiation) did not significantly reduce this natural growth inhibition. By contrast, Holder pasteurisation significantly reduced the milk’s natural antimicrobial effect on S. aureus growth after 6 h (−19.8% p = 0.01). Freeze-dried and then gamma-irradiated donor human milk showed a strong antimicrobial effect across a dose range of 2–50 kGy, with only a minimal growth of S. aureus observed after 6 h incubation. Thus, a hybrid method of freeze-drying followed by 2 kGy of gamma-irradiation preserves antimicrobial properties and enables bulk pasteurisation within sealed packaging of powderised donor human milk. This work forwards a goal of increasing shelf life and simplifying storage and transportation, while also preserving functionality and antimicrobial properties.

"Donor milk banking: Improving the future". A survey on the operation of the European donor human milk banks

BACKGROUND

Provision of donor human milk is handled by established human milk banks that implement all required measures to ensure its safety and quality. Detailed human milk banking guidelines on a European level are currently lacking, while the information available on the actual practices followed by the European human milk banks, remains limited. The aim of this study was to collect detailed data on the actual milk banking practices across Europe with particular emphasis on the practices affecting the safety and quality of donor human milk.

MATERIALS AND METHODS

A web-based questionnaire was developed by the European Milk Bank Association (EMBA) Survey Group, for distribution to the European human milk banks. The questionnaire included 35 questions covering every step from donor recruitment to provision of donor human milk to each recipient. To assess the variation in practices, all responses were then analyzed for each country individually and for all human milk banks together.

RESULTS

A total of 123 human milk banks completed the questionnaire, representing 85% of the European countries that have a milk bank. Both inter- and intra-country variation was documented for most milk banking practices. The highest variability was observed in pasteurization practices, storage and milk screening, both pre- and post-pasteurization.

CONCLUSION

We show that there is a wide variability in milk banking practices across Europe, including practices that could further improve the efficacy of donor human milk banking. The findings of this study could serve as a tool for a global discussion on the efficacy and development of additional evidence-based guidelines that could further improve those practices.

Human Milk from Previously COVID-19-Infected Mothers: The Effect of Pasteurization on Specific Antibodies and Neutralization Capacity

BACKGROUND

Since the outbreak of coronavirus disease 2019 (COVID-19), many put their hopes in the rapid availability of effective immunizations. Human milk, containing antibodies against syndrome coronavirus 2 (SARS-CoV-2), may serve as means of protection through passive immunization. We aimed to determine the presence and pseudovirus neutralization capacity of SARS-CoV-2 specific IgA in human milk of mothers who recovered from COVID-19, and the effect of pasteurization on these antibodies.

METHODS

This prospective case control study included lactating mothers, recovered from (suspected) COVID-19 and healthy controls. Human milk and serum samples were collected. To assess the presence of SARS-CoV-2 antibodies we used multiple complementary assays, namely ELISA with the SARS-CoV-2 spike protein (specific for IgA and IgG), receptor binding domain (RBD) and nucleocapsid (N) protein for IgG in serum, and bridging ELISA with the SARS-CoV-2 RBD and N protein for specific Ig (IgG, IgM and IgA in human milk and serum). To assess the effect of pasteurization, human milk was exposed to Holder (HoP) and High Pressure Pasteurization (HPP).

RESULTS

Human milk contained abundant SARS-CoV-2 antibodies in 83% of the proven cases and in 67% of the suspected cases. Unpasteurized milk with and without these antibodies was found to be capable of neutralizing a pseudovirus of SARS-CoV-2 in (97% and 85% of the samples respectively). After pasteurization, total IgA antibody levels were affected by HoP, while SARS-CoV-2 specific antibody levels were affected by HPP. Pseudovirus neutralizing capacity of the human milk samples was only retained with the HPP approach. No correlation was observed between milk antibody levels and neutralization capacity.

CONCLUSIONS

Human milk from recovered COVID-19-infected mothers contains SARS-CoV-2 specific antibodies which maintained neutralization capacity after HPP. All together this may represent a safe and effective immunization strategy after HPP.

Changes in bioactive proteins and serum proteome of human milk under different frozen storage

This study aimed to investigate changes in macronutrients, total bacterial count, and serum proteome of human milk (HM) under different frozen storage (-18°C and -60°C, 60 d and 180 d) by using IBT Labeling proteomics techniques and ELISA kit. The results indicated that total protein concentrations and total aerobic bacterial counts were significantly decreased at -18°C, while no difference at -60°C. A total of 1617 proteins were identified and quantified, and 173 proteins were significantly different. The -18°C storage had much higher influence on HM serum protein profiles than that of -60°C. Increased milk fat globule membrane (MFGM) proteins at -18°C are highly related to the damage of MFGM and transfer of MFGM proteins. The reduction of bioactive proteins is probably related to the ice-induced denaturation. In conclusion, fast cooling and ultra-low constant temperature are more suitable for the cryopreservation of human milk.

Human Colostrum and Derived Extracellular Vesicles Prevent Infection by Human Rotavirus and Respiratory Syncytial Virus in Vitro

BACKGROUND

It is known that breastfeeding protects the infant from enteric and respiratory infections; however, the antiviral properties of human milk against enteric and respiratory viruses are largely unexplored.

RESEARCH AIMS

To explore the antiviral activity of human preterm colostrum against rotavirus and respiratory syncytial virus and to assess whether the derived extracellular vesicle contribute to this activity.

METHODS

We used a cross-sectional, prospective two-group non-experimental design. Colostra were collected from mothers of preterm newborns (N = 10) and extracellular vesicles were purified and characterized. The antiviral activity of colostra and derived extracellular vesicles were tested in vitro against rotavirus and respiratory syncytial virus and the step of viral replication inhibited by extracellular vesicles was investigated.

RESULTS

Each sample of colostrum and colostrum-derived extracellular vesicles had significant antiviral activity with a wide interpersonal variability. Mechanism of action studies demonstrated that extracellular vesicles acted by interfering with the early steps of the viral replicative cycle.

CONCLUSION

We demonstrated the intrinsic antiviral activity of human colostrum against rotavirus and respiratory syncytial virus and we showed that extracellular vesicles substantially contribute to the overall protective effect. Our results contribute to unravelling novel mechanisms underlying the functional role of human milk as a protective and therapeutic agent in preterm infants.

Maternal Transmission of SARS-CoV-2: Safety of Breastfeeding in Infants Born to Infected Mothers

Coronavirus disease 2019 (COVID-19) is a recent epidemic disease caused by severe acute respiratory syndrome virus type 2 (SARS-CoV-2). In pregnancy, SARS-Cov-2 infection creates additional alarm due to concerns regarding the potential for transmission from the mother to the baby during both the antenatal and postpartum times. In general, breastfeeding is seldom disallowed because of infection of the mother. However, there are few exceptions with regards to certain infectious organisms with established transmission evidence from mother to infant and the link of infection of a newborn with significant morbidity and mortality. It is confirmed that pregnant women can become infected with SARS-CoV-2, although the debate on the possible vertical transmission of SARS-CoV-2 infection during pregnancy is still open. In this regard, the literature is still poor. On the contrary, the information on the safety of breastfeeding even during infections seems reassuring when the mother takes the necessary precautions. However, there are still answered questions regarding the precautions to be taken during breastfeeding by COVID-19 patients. This paper reviews the existing answers to these and many other questions. This review therefore presents a summary of the present-day understanding of infection with SARS-CoV-2 and discusses the answers around the maternal transmission of COVID-19 and the potential threat of breastfeeding to babies born to infected pregnant mothers. In conclusion, intrauterine transmission of SARS-CoV-2 infection is less likely to occur during pregnancy. Most studies suggest that COVID-19 is not transmitted through breast milk. Correspondingly, COVID-19-infected neonates might acquire the infection via the respiratory route because of the postnatal contact with the mother rather than during the prenatal period. International organizations encourage breastfeeding regardless of the COVID-19 status of the mother or child as long as proper hygienic and safety measures are adhered to so as to minimize the chance of infant infection by droplets and direct contact with the infected mother. Pasteurized donor human milk or infant formula as supplemental feeding can be quite beneficial in the case of mother-infant separation till breastfeeding is safe.

High-Temperature Short-Time Preserves Human Milk's Bioactive Proteins and Their Function Better Than Pasteurization Techniques With Long Processing Times

Donor human milk is generally processed by holder pasteurization (HoP) at 62. 5°C for 30 min. This temperature-time combination is sufficient for eliminating pathogens in donor milk, but also negatively affects several bioactive milk components. Long heating up times may further affect the bioactive properties of pasteurized milk. High-Temperature-Short-Time (HTST), a treatment with shorter processing times (72°C for 15 sec), was investigated as a suitable alternative to HoP. In addition, pasteurization methods that follow the same temperature regime but with varying heating up times were compared. Human milk samples from four different donors were combined into one pool, which was then used to perform all analyses. The effects of these methods on the levels and functionality of immunoglobulin A, lactoferrin, lysozyme and bile salt-stimulated lipase, were evaluated with LC-MS/MS-based proteomics and activity assays, while the pasteurization efficacy was evaluated with an alkaline phosphatase test. HoP, a treatment with long processing times, times, caused the highest reduction in all proteins studied (reduced by 50-98%). Compounds such as lactoferrin and bile salt-stimulated lipase that are more sensitive to heat treatments were better retained with HTST, but their levels and functionality were still significantly lower than those of untreated donor milk (52 and 81% reduction of lactoferrin and bile salt-stimulated lipase activity, respectively). Our findings showed that a treatment with considerably shorter processing times, such as HTST, may reduce the thermal damage caused to the bioactive proteins compared to HoP, without affecting pasteurization efficacy. Since the vast majority of the donor human milk banks that are currently operating on a global level apply HoP to donor milk, our findings may provide relevant information for the optimization of donor milk processing.

Bile Salt-Stimulated Lipase Activity in Donor Breast Milk Influenced by Pasteurization Techniques

Breast milk contains bile salt-stimulated lipase (BSSL), which significantly increases the fat digestion capacity of newborns who have limited pancreatic lipase secretion in the first few months after birth. Problematically, Holder pasteurization used in non-profit milk banks to ensure the microbiological safety of donor milk for infants, particularly preterm infants (<37 weeks gestation age), destroys milk BSSL, thus limiting infant fat absorption capacity. Alternative strategies are needed to ensure the safety of donor milk while preserving BSSL activity. Three alternative pasteurization techniques—high-pressure processing (HPP, 550 MPa, 5 min), gamma cell irradiation (IR, 2.5 Mrads) and UV-C (254 nm, 0–33,000 J/L)—were compared with Holder pasteurization (low-temperature long-time, LTLT, 62.5°C, 30 min) for retention of BSSL activity in donor breast milk. As the time required for donor milk pasteurization by UV-C in published methods was not clear, donor breast milk was spiked with seven common bacterial strains and treated by UV-C for variable time periods and the minimum UV-C dosage required to achieve a 5-log₁₀ reduction of CFU/mL was determined. Eight thousand two hundred fifty J/L of UV-C exposure was sufficient to achieve 5-log₁₀ reduction of each of bacterial targets, including Bacillus and Paenibacillus spores. The retention of BSSL activity was highest after HPP (retaining 62% of the untreated milk BSSL activity), followed by UV-C (16,500 J/L), IR and LTLT (35, 29, and 0.3% retention, respectively). HPP was an effective alternative to pasteurize milk with improved retention of BSSL activity compared to Holder pasteurization. Future work should investigate the effect of alternative pasteurization techniques on the entire array of bioactive components in donor breast milk and how these changes affect preterm infant health outcomes. Implementation of HPP technique at milk banks could improve donor milk-fed infant fat absorption and growth.

Ovarian Transcriptomic Analysis Reveals Differential Expression Genes Associated with Cell Death Process after Selection for Ovulation Rate in Rabbits

Simple Summary

Transcriptomic analysis showed nineteen potential biomarkers in ovarian tissue from females belonged to a rabbit line selected for ovulation rate for 10 generations and the control line. These females differed not only in ovulation rate but also in prenatal survival since similar litter size were observed.

Abstract

Litter size is an essential trait in rabbit meat production but with low heritability. A selection experiment for ovulation rate has been performed for 10 generations to improve litter size in rabbits. The selected line increased two ova more than the control line but nevertheless a negative correlation was observed with prenatal survival. A transcriptomic study was performed, using microarrays, in ovarian tissue from females belonging to the selected line and the control line. Our results showed 1357 differential expressed genes and nineteen potential biomarkers associated with prenatal mortality, which could explain differences between litter size in rabbits. Cell death was the most relevant process.

Anti-Zika virus and anti-Usutu virus activity of human milk and its components

The benefits of human milk are mediated by multiple nutritional, trophic, and immunological components, able to promote infant's growth, maturation of its immature gut, and to confer protection against infections. Despite these widely recognized properties, breast-feeding represents an important mother-to-child transmission route of some viral infections. Different studies show that some flaviviruses can occasionally be detected in breast milk, but their transmission to the newborn is still controversial. The aim of this study is to investigate the antiviral activity of human milk (HM) in its different stages of maturation against two emerging flaviviruses, namely Zika virus (ZIKV) and Usutu virus (USUV) and to verify whether HM-derived extracellular vesicles (EVs) and glycosaminoglycans (GAGs) contribute to the milk protective effect. Colostrum, transitional and mature milk samples were collected from 39 healthy donors. The aqueous fractions were tested in vitro with specific antiviral assays and EVs and GAGs were derived and characterized. HM showed antiviral activity against ZIKV and USUV at all the stages of lactation with no significant differences in the activity of colostrum, transitional or mature milk. Mechanism of action studies demonstrated that colostrum does not inactivate viral particles, but it hampers the binding of both flaviviruses to cells. We also demonstrated that HM-EVs and HM-GAGs contribute, at least in part, to the anti-ZIKV and anti-USUV action of HM. This study discloses the intrinsic antiviral activity of HM against ZIKV and USUV and demonstrates the contribution of two bioactive components in mediating its protective effect. Since the potential infectivity of HM during ZIKV and USUV infection is still unclear, these data support the World Health Organization recommendations about breast-feeding during ZIKV infection and could contribute to producing new guidelines for a possible USUV epidemic.

Extracellular Vesicles in Human Preterm Colostrum Inhibit Infection by Human Cytomegalovirus In Vitro

Breast milk is a complex biofluid that nourishes infants, supports their growth and protects them from diseases. However, at the same time, breastfeeding is a transmission route for human cytomegalovirus (HCMV), with preterm infants being at a great risk of congenital disease. The discrepancy between high HCMV transmission rates and the few reported cases of infants with severe clinical illness is likely due to the protective effect of breast milk. The aim of this study was to investigate the anti-HCMV activity of human preterm colostrum and clarify the role of colostrum-derived extracellular vesicles (EVs). Preterm colostrum samples were collected and the EVs were purified and characterized. The in vitro anti-HCMV activity of both colostrum and EVs was tested against HCMV, and the viral replication step inhibited by colostrum-purified EVs was examined. We investigated the putative role EV surface proteins play in impairing HCMV infection using shaving experiments and proteomic analysis. The obtained results confirmed the antiviral action of colostrum against HCMV and demonstrated a remarkable antiviral activity of colostrum-derived EVs. Furthermore, we demonstrated that EVs impair the attachment of HCMV to cells, with EV surface proteins playing a role in mediating this action. These findings contribute to clarifying the mechanisms that underlie the protective role of human colostrum against HCMV infection.

The impact of thermal pasteurization on viral load and detectable live viruses in human milk and other matrices: a rapid review

Holder pasteurization (62.5 °C, 30 min) of human milk is thought to reduce the risk of transmitting viruses to an infant. Some viruses may be secreted into milk - others may be contaminants. The effect of thermal pasteurization on viruses in human milk has yet to be rigorously reviewed. The objective of this study is to characterize the effect of common pasteurization techniques on viruses in human milk and non-human milk matrices. Databases (MEDLINE, Embase, Web of Science) were searched from inception to April 20th, 2020, for primary research articles assessing the impact of pasteurization on viral load or detection of live virus. Reviews were excluded, as were studies lacking quantitative measurements or those assessing pasteurization as a component of a larger process. Overall, of 65 131 reports identified, 109 studies were included. Pasteurization of human milk at a minimum temperature of 56-60 °C is effective at reducing detectable live virus. In cell culture media or plasma, coronaviruses (e.g., SARS-CoV, SARS-CoV-2, MERS-CoV) are highly susceptible to heating at ≥56 °C. Although pasteurization parameters and matrices reported vary, all viruses studied, except parvoviruses, were susceptible to thermal killing. Future research important for the study of novel viruses should standardize pasteurization protocols and should test inactivation in human milk. Novelty In all matrices, including human milk, pasteurization at 62.5 °C was generally sufficient to reduce surviving viral load by several logs or to below the limit of detection. Holder pasteurization (62.5 °C, 30 min) of human milk should be sufficient to inactivate nonheat resistant viruses, including coronaviruses, if present.

Early-Life Gut Microbiome-The Importance of Maternal and Infant Factors in Its Establishment

The early-life microbiome is gaining appreciation as a major influencer in human development and long-term health. Multiple factors are known to influence the initial colonization, development, and function of the neonatal gut microbiome. In addition, alterations in early-life gut microbial composition is associated with several chronic health conditions such as obesity, asthma, and allergies. In this review, we focus on both maternal and infant factors known to influence early-life gut colonization. Also reviewed is the important role of infant feeding, including evidence-based strategies for maternal and infant supplementation with the goal to protect and/or restore the infant gut microbiome.

Effect of Alternative Pasteurization Techniques on Human Milk's Bioactive Proteins

OBJECTIVES

Human milk (HM) feeding leads to improved outcome for preterm infants. When mother's milk is unavailable, pasteurized donor HM (DHM) is the recommended alternative over formula. The Holder pasteurization (HoP) method is universally performed in HM banks; however, it is known to impair several functional HM components. The aim of this study was to compare the efficacy of HoP with 2 innovative processing methods (high-temperature short-time [HTST] pasteurization and high-pressure processing [HPP]) in preserving some bioactive HM protein components.

METHODS

HM samples from donors of the Bologna HM bank were collected and divided into 4 subsamples: 1 was kept raw, and each of the others was processed using a different technique (HoP, HTST, and HPP at 600 MPa for 3 minutes). Total protein content, secretory immunoglobulin A (sIgA), and lactoferrin contents were compared.

RESULTS

Both HM lactoferrin and sIgA content were negatively affected, but to a different extent, by each method: sIgA was preserved by HTST, with only HPP leading to a significant reduction (-38.8%); lactoferrin content was strongly reduced by HoP (-87.5%) and HTST (-83.5%), and preserved by HPP. Variations in protein profile were seen for all processing methods, being more relevant for HoP, followed by HTST and, finally, by HPP. All the 3 methods lowered the untreated HM microbial counts to undetectable levels, in accordance with national guidelines.

CONCLUSIONS

Both HTST and HPP better preserved the original HM protein profile, compared to HoP. They, however, affected differently some bioactive HM components involved in immune response and antibacterial activity.

Effect of Target Fortification on Osmolality and Microbiological Safety of Human Milk Over Time

OBJECTIVES

The fortification of human milk can result in increased osmolality, which may be associated with adverse effects for preterm infants. To evaluate the effect of target fortification on the osmolality and microbiological safety of donor human milk and raw mature milk during the first 72 hours of storage.

METHODS

We performed target fortification of 63 pasteurized donor human milk (PDHM) and 54 raw mature milk (RMM) samples in a laminar flow hood. Osmolality (mOsm/kg) was evaluated before fortification (T0), immediately after fortification (T1), at 6 (T2), 24 (T3), 48 (T4), and 72 hours (T5) after fortification. Microbiological analysis was performed at T0, T4, and T5. During the study, all samples were stored at 4°C.

RESULTS

Mean osmolality at each study point for PDHM and RMM were, respectively: T0: 291.4 ± 11.0 versus 288.4 ± 5.6 (P = 0.06); T1: 384.8 ± 16.7 versus 398.3 ± 23.7; T2: 393.9 ± 17.7 versus 410.1 ± 27.0; T3: 397.8 ± 17.6 versus 417.9 ± 26.1; T4: 400.0 ± 16.5 versus 420.2 ± 24.9; T5: 399.6 ± 16.5 versus 425.2 ± 25.8 (P < 0.001 from T1 to T5). Microbiological analyses were negative at each study points for PDHM. At T0 16.1% of RMM samples had positive cultures, whereas the bacterial count remained stable thought the study.

CONCLUSIONS

PDHM's osmolality increases during the first 6 hours after fortification and remains stable and safe until 72 hours. RMM's osmolality increases during the first 24 hours and remains stable and safe until 72 hours. The storage at 4°C and the manipulation of PDHM and RMM samples in a laminar flow hood seem to be safe and preserve the microbiological safety of fortified pasteurized human milk until 72 hours.

Policy statement of enteral nutrition for preterm and very low birthweight infants

For preterm and very low birthweight infants, the mother's own milk is the best nutrition. Based on the latest information for mothers who give birth to preterm and very low birthweight infants, medical staff should encourage and assist mothers to pump or express and provide their own milk whenever possible. If the supply of maternal milk is insufficient even though they receive adequate support, or the mother's own milk cannot be given to her infant for any reason, donor human milk should be used. Donors who donate their breast milk need to meet the Guideline of the Japan Human Milk Bank Association. Donor human milk should be provided according to the medical needs of preterm and very low birthweight infants, regardless of their family's financial status. In the future, it will be necessary to create a system to supply an exclusive human milk-based diet (EHMD), consisting of human milk with the addition of a human milk-derived human milk fortifier, to preterm and very low birthweight infants.

Evaluation of the Tempo® System: Improving the Microbiological Quality Monitoring of Human Milk

Background: Bacteriological testing of donor human milk is mostly done both before and after pasteurization to control contamination in the end-product and meet the microbiological standards. Although the plate count method represents a reliable and sensitive technique and is considered the gold standard for bacteriological testing, it is recognized for being time-consuming and requiring qualified personnel. Recently, faster testing technologies, mostly geared toward the food industry, have been developed. Among these, the bioMérieux TEMPO® system uses the most probable number method to assess microbiological content in a semi-automated fashion. Objective: The performances of the TEMPO® system in enumerating bacterial quality indicators in human milk were assessed and compared to the reference plate count method. Methods: Naturally and artificially contaminated human milk samples were used to compare the analytical performances of the TEMPO® system to the plate count technique. More specifically, bacteria belonging to the genera Bacillus, Enterobacteriaceae, Staphylococcus aureus, and total aerobic flora were screened using both methods. Bacteria isolated on agar plates containing selective media were identified by supplemental testing. Bacterial testing results and method parameters were compared using linear regression analyses and Bland-Altman approaches. Results: Naturally contaminated milk samples (n = 55) tested for total aerobic flora showed < 1 log (CFU/ml) discrepancy between the two methods in the output results for 98% of the samples. Comparative linear regression analyses demonstrate good correlations between the two methods (R ² > 0.9). At lower levels of bacterial contamination, the TEMPO® method precision (C.V. < 8%) and accuracy (> 83%) were comparable to plate counts. Conclusions: The analytical performances of the TEMPO® system for human milk bacteriological testing are equivalent to the reference plate count method. Results from the TEMPO® system are available within a 24-h turnaround time from sample inoculation without the need for further supplemental testing, suggesting that this semi-automated method could be implemented within milk bank operations as an in-process monitoring technology to optimize end-product quality and safety.

Human Milk's Hidden Gift: Implications of the Milk Microbiome for Preterm Infants' Health

Breastfeeding is considered the gold standard for infants' nutrition, as mother's own milk (MOM) provides nutritional and bioactive factors functional to optimal development. Early life microbiome is one of the main contributors to short and long-term infant health status, with the gut microbiota (GM) being the most studied ecosystem. Some human milk (HM) bioactive factors, such as HM prebiotic carbohydrates that select for beneficial bacteria, and the specific human milk microbiota (HMM) are emerging as early mediators in the relationship between the development of GM in early life and clinical outcomes. The beneficial role of HM becomes even more crucial for preterm infants, who are exposed to significant risks of severe infection in early life as well as to adverse short and long-term outcomes. When MOM is unavailable or insufficient, donor human milk (DHM) constitutes the optimal nutritional choice. However, little is known about the specific effect of DHM on preterm GM and its potential functional implication on HMM. The purpose of this narrative review is to summarize recent findings on HMM origin and composition and discuss the role of HMM on infant health and development, with a specific focus on preterm infants.

The effects of storage conditions on long-chain polyunsaturated fatty acids, lipid mediators, and antioxidants in donor human milk - A review

Donor human milk (DHM) is the recommended alternative, if maternal milk is unavailable. However, current human milk banking practices may negatively affect the nutritional quality of DHM. This review summarises the effects of these practices on polyunsaturated fatty acids, lipid mediators and antioxidants of human milk. Overall, there is considerable variation in the reported effects, and further research is needed, particularly with lipid mediators and antioxidants. However, to preserve nutritional quality, DHM should be protected from light exposure and storage at 4 °C minimised, to prevent decreases in vitamin C and endocannabinoids and increases in free fatty acids and lipid peroxidation products. Storage at -20 °C prior to pasteurisation should also be minimised, to prevent free fatty increases and total fat and endocannabinoid decreases. Storage ≤-70 °C is preferable wherever possible, although post-pasteurisation storage at -20 °C for three months appears safe for free fatty acids, lipid peroxidation products, and total fat content.

Comparison of two methods for cleaning breast pump milk collection kits in human milk banks

BACKGROUND

Appropriate decontamination of breast pump milk collection kits (BPKs) is critical to obtain safe milk for infants and to avoid discarding donor human milk (DHM).

AIM

To evaluate two strategies for BPK decontamination by assessing microbial cultures and the proportion of discarded DHM, according to the criteria of the National Institute for Health and Care Excellence for pre-pasteurization cultures.

METHODS

Prospective comparative study, allocation ratio 1:1, microbiologist-blind.

PARTICIPANTS

47 new donors in a human milk bank in Madrid.

INTERVENTIONS

Study group (N=21): BPKs washed with water and detergent after each use and further steam decontamination within a microwavable bag. Control group (N=26): washing, rinsing and drying only. Five samples: first sample by hand expression and four samples (one per week) collected using the same pump and method.

OUTCOMES

Primary: proportion of DHM discarded due to contamination. Secondary: comparison of the microbiota between samples obtained by hand expression and breast pump in both groups.

FINDINGS

In total, 217 milk samples were collected: 47 by hand expression and 170 by pump expression (78 from study group). Steam decontamination of BPKs using a microwavable bag after washing resulted in a lower proportion of discarded DHM samples (1.3% vs 18.5%, P<0.001) and samples contaminated with Enterobacteriaceae (1.3% vs 22.8%, P<0.001) and Candida spp. (1.3% vs 14.1%, P<0.05) compared with samples collected with BPKs that were washed but not steam decontaminated. There were no differences in bacterial contamination between samples obtained using steam decontaminated BPKs and those obtained by hand expression.

CONCLUSIONS

Steam decontamination of BPKs using a microwavable bag after washing decreases the amount of discarded DHM and the number of samples with potentially pathogenic bacteria.

Stakeholder Attitudes towards Donating and Utilizing Donated Human Breastmilk

The promotion and support of human milk banks (HMBs) can enhance exclusive breastfeeding rates. The success and sustainability of HMBs depend on the support from relevant healthcare workers and related communities. This study aimed to determine attitudes of key stakeholders, including mothers, healthcare workers and grandmothers, regarding the donation and receipt of human breastmilk. This study was conducted at a public hospital and clinics in the North West Province, South Africa. Eight focus group discussions explored the attitudes regarding donating and receiving human breastmilk: three groups with mothers of infants (n = 13), three with grandmothers (>60 years old) (n = 17) and two with healthcare professionals working with infants (n = 11). Four main themes emerged: perception regarding breast and formula feeding; exposure to the concept of “wet nursing”; breastmilk donation; and utilization and opinions of community members and traditional healers. Specific barriers identified included the processes for donating and receiving milk, safety, human immuno-deficiency virus (HIV) screening and cultural beliefs. Mothers’ fears included having insufficient milk for their own infants, changes in the quality of donated milk during pasteurization and transportation and HIV transmission. Despite barriers towards donations to and the use of HMBs, sufficient information could enhance donations by mothers and breastmilk utilization.