Influence of prolonged storage process, pasteurization, and heat treatment on biologically-active human milk proteins

Community Practices, Published Guidelines, and Evidence Base Surrounding Breast Milk Handling and Storage: A Qualitative Study

Background: Expressed breast milk (EBM) is the best alternative to direct breastfeeding. However, expressing breast milk requires good milk handling and storage practices to preserve EBM safety and integrity. Mothers require handling and storage guidance, and many seek this from the internet and online support groups. Aim: This study aimed at exploring EBM handling and storage practices within an online exclusively expressing community and comparing these with both internet resources and evidence-based research. Methods: A naturalistic observational design was used. Content analysis was undertaken on 10,000 posts from an Australian Facebook peer-support community for women who exclusively express breast milk. Women's questions, reported practices, and advice for EBM handling and storage were analyzed thematically and compared with both guidelines and evidence-based research. Findings: There were 460 posts on EBM handling and storage. Three key themes emerged: "How should I store my EBM?," "How long can I store my EBM?," and "How do I use my EBM?" The greatest consistency and agreement between recommendations and community practices were found for storage methods, whereas the least was found for storage times. EBM handling and storage practices were influenced by factors such as EBM value, convenience, and cost, leading to occasional deviations from consistent practice recommendations. Conclusion: To facilitate safe EBM handling and continuation of expression, guidelines should be updated so they are consistent, align with current evidence, and cater to mothers' cost, convenience, and milk wastage concerns. Health care providers can partner with women to evaluate online information to empower mothers in their decision making.

Effects of Different Thawing and Warming Processes on Human Milk Composition

The composition of human milk is influenced by storage and processing practices. The effects of thawing and warming practices on human milk composition remain poorly studied despite their prevalence in home, research, and donor milk bank settings. This review comprehensively examines the impact of different thawing and warming methods on nutritional and bioactive human milk components. While some components such as carbohydrates and minerals remain stable under most typical thawing and warming conditions, others, such as fat, immune proteins, bacterial and human cells, and peptide amine hormones, are sensitive to warming. This review has identified that the data on the effects of milk thawing and warming is limited and often contradictory. Given that numerous important components of milk are diminished during cold storage, it is important that thawing and warming practices do not lead to further loss of or alterations to beneficial milk components. Further work in this field will facilitate greater standardization of thawing methods among researchers and underpin recommendations for thawing and warming of expressed milk for parents.

The impact of thawing duration on leptin and adiponectin levels in frozen human milk samples

BACKGROUND

Measurements of hormone concentrations in human milk from understudied populations across the world is of growing scientific interest. Due to limited access to suitable laboratory facilities at many research sites, human milk samples are often shipped frozen to distant laboratories for analysis. Shipping and handling exposes samples to the risk of thawing and degradation as the results of delays, mishandling, or other unforeseen circumstances. Similar degradation risk factors are well known in serum samples. However, the vulnerability of hormone degradation in human milk to thawing during transportation is largely unexplored. Leptin and adiponectin are of particular importance due to their roles in feeding behavior and metabolism in infants, hence our focus on these two hormones. In addition, leptin and adiponectin have been shown to be vulnerable to pasteurization temperature degradation in human milk samples.

AIMS

We tested the degradation of human milk metabolic hormones - leptin and adiponectin - in a controlled environment in response to a variety of freeze/thaw conditions that are reflective of potential temperature fluctuations during transportation.

MATERIALS & METHODS

Human milk samples were experimentally subjected to thaw durations ranging from 4 to 16 h and assayed for hormonal levels to observe changes from baseline. Samples were also subjected to two additional experimental conditions, re-freezing after an extended period outside freezers or remaining thawed with additional ice packs, to investigate the impact of common transportation conditions.

RESULTS

We found the assayed levels of leptin were not significantly impacted by an extended thaw cycle of 16 h. However, leptin levels were impacted by the extended period of 40 h outside of the freezer. Adiponectin showed a decrease in concentration percentage after the initial 16-h thaw period, but the increased degradation between 0-16 h and 16-40 h was not as severe as that seen in the leptin samples.

DISCUSSION & CONCLUSION

The results of this experiment can be used to inform hormone measurement consistency given different thawing lengths or freezing conditions during transportation. Additionally, this research informs decisions regarding transportation, storage/handling, and data analysis in human milk research.

Pasteurization of human milk affects the miRNA cargo of EVs decreasing its immunomodulatory activity

In this report, we evaluated the effect of the pasteurization (P) process of mother's own milk (MOM) on the miRNA content of extracellular vesicles (EVs) and its impact on innate immune responses. Differences in size or particle number were not observed upon pasteurization of MOM (PMOM). However, significant differences were observed in the EV membrane marker CD63 and miRNA profiles. miRNA sequencing identified 33 differentially enriched miRNAs between MOM_EV and PMOM_EV. These changes correlated with significant decreases in the ability of PMOM_EV to modulate IL-8 secretion in intestinal Caco2 cells where only MOM_EV were able to decrease IL-8 secretion in presence of TNFα. While EVs from MOM_EV and PMOM_EV were both able to induce a tolerogenic M2-like phenotype in THP-1 macrophages, a significant decrease in the transcript levels of IL-10 and RNA sensing genes was observed with PMOM_EV. Together, our data indicates that pasteurization of MOM impacts the integrity and functionality of MOM_EV, decreasing its EVs-mediated immunomodulatory activity. This data provides biomarkers that may be utilized during the optimization of milk processing to preserve its bioactivity.

Ecologies, synergies, and biological systems shaping human milk composition-a report from "Breastmilk Ecology: Genesis of Infant Nutrition (BEGIN)" Working Group 2

Human milk is universally recognized as the preferred food for infants during the first 6 mo of life because it provides not only essential and conditionally essential nutrients in necessary amounts but also other biologically active components that are instrumental in protecting, communicating important information to support, and promoting optimal development and growth in infants. Despite decades of research, however, the multifaceted impacts of human milk consumption on infant health are far from understood on a biological or physiological basis. Reasons for this lack of comprehensive knowledge of human milk functions are numerous, including the fact that milk components tend to be studied in isolation, although there is reason to believe that they interact. In addition, milk composition can vary greatly within an individual as well as within and among populations. The objective of this working group within the Breastmilk Ecology: Genesis of Infant Nutrition (BEGIN) Project was to provide an overview of human milk composition, factors impacting its variation, and how its components may function to coordinately nourish, protect, and communicate complex information to the recipient infant. Moreover, we discuss the ways whereby milk components might interact such that the benefits of an intact milk matrix are greater than the sum of its parts. We then apply several examples to illustrate how milk is better thought of as a biological system rather than a more simplistic "mixture" of independent components to synergistically support optimal infant health.

The effects of freezing and thawing on mature human milk's contains: A systematic review

OBJECTIVE

To conduct a systematic review on the effects of freezing and thawing mature human milk at -18 to -20°C for different periods of time on the macronutrients, micronutrients and bioactive content of milk.

DESIGN

Before starting the research, the study protocol was recorded in the 'PROSPERO' database. Eleven databases were searched, and eight studies were included in this review. The articles were published between January 2010 and June 2020.

MEASUREMENTS AND FINDINGS

Total protein content increased when milk was frozen for 2 days, but this decreased significantly when milk was frozen for >1 week. Total carbohydrate content also increased when milk was frozen for 2 days, and no significant change was observed when milk was frozen for >1 week. Energy content decreased when milk was frozen for >8 weeks. Total fat content decreased as the freezing period of milk increased, and total free fatty acid content increased. Thirty days of freezing led to a non-significant decrease in the vitamin E content of milk. Freezing did not lead to changes in immunological factors in human milk, but decreases in glutathione peroxidase, antioxidant capacity and lactoferrin were observed.

KEY CONCLUSIONS

In order to maintain the nutritional and immunological properties of human milk after freezing and thawing, families, especially mothers, should be informed about the effects of storing milk this way. After expressing milk, it is recommended that the date should be written on the freezer bag, so that milk is frozen for a shorter period of time before use.

Quantification of lactoferrin in human milk using monolithic cation exchange HPLC

Human lactoferrin (hLF) is one of the most important whey proteins in human milk, known for its ability to modulate innate host immunity and multifunctional activities for neonatal growth. The objective of this study was to validate an efficient method for the detection and quantification of hLF using a unique technology of cation-exchange high-performance liquid chromatography (HPLC) on CIM® monolithic columns. Human milk samples were collected using manual expression or a breast pump, at different weeks of lactation. After sample preparation, hLF was detected and measured by HPLC method and further confirmed by SDS-PAGE. Selected fractions were analysed also by LC-MS/MS. Presumably, due to the high density of positive charge on the surface of the N-terminal domain, hLF binds strongly to the column and elutes last, enabling the high specificity of this method. The LC-MS/MS analysis indicated that hLF eluted in two clearly separated peaks, presumably representing two different molecular species of hLF. hLF concentration in the human milk samples ranged from 2.03 mg/mL to 5.79 mg/mL and was not significantly affected by the sample collection method whereas it was negatively correlated with the stage of lactation. These results suggest that cation exchange chromatography is an accurate, efficient, and robust method for the detection and quantification of hLF.

Sterilization efficacy of a new water-free breast milk pasteurizer

BACKGROUND

Breast milk, nature's optimum source of nutrition for infants, can contain undesirable microorganisms that cause severe morbidity. After an outbreak of multidrug-resistant Escherichia coli among neonates receiving breast milk donated by another mother in our neonatal intensive care unit (NICU), we were motivated to develop a high-grade breast milk pasteurizer (BMP) designed to thaw and pasteurize breast milk at 63°C for 30 min in a sealed bag without having to open the bag or immerse it in water.

METHODS

Pre-existing bacteria and spiked cytomegalovirus (CMV) were measured pre- and post-pasteurization in frozen breast milk donated by mothers of children admitted to the NICU.

RESULTS

Among 48 breast milk samples (mean ± standard deviation [SD]), pre-existing bacterial counts of 5.1±1.1 × 104 colony forming units (cfu)/mL decreased to less than 10 cfu/mL (below detection level) in 45 samples after pasteurization for 30 min. In three samples, 10-110 cfu/mL persisted. As no CMV was detected in any of the 48 samples, CMV at ≥5 × 104 pfu/mL was spiked into 11 breast milk samples. After just 10 min of pasteurization, infectious CMV was not detected (threshold <50 pfu/mL) in any sample.

CONCLUSION

A new BMP was shown to pasteurize milk effectively with more than a 3-log reduction of microorganisms. Compared to conventional pasteurizers, this device reduces the effort involved in pasteurizing breast milk, avoids various contamination risks, and may reduce the risk of infectious disease transmission via breast milk.

Nesfatin-1 in Human Milk and Its Association with Infant Anthropometry

Breastfed infants have different growth patterns to formula-fed infants and are less likely to develop obesity later in life. Nesfatin-1 is an anorexigenic adipokine that was discovered in human milk more than a decade ago, and its role in infant appetite regulation is not clear. Our aim was to describe nesfatin-1 levels in human milk collected 3-4 months postpartum, associations with infant anthropometry, and factors (maternal pre-pregnancy body mass index (mBMI), high weight gain during pregnancy, milk fat, and energy content) possibly influencing nesfatin-1 levels. We hypothesized that nesfatin-1 levels in mother's milk would differ for infants that were large (high weight-for-age Z-score (WAZ)) or small (low WAZ) at the time of milk sample collection. We used enzyme-linked immunosorbent assay to detect the nesfatin-1 concentration in milk samples from mothers to high WAZ (n = 50) and low WAZ (n = 50) infants. We investigated associations between nesfatin-1 levels and infant anthropometry at 3-4 months of age and growth since birth, using linear regression adjusted for mBMI, birth weight, infant sex, and exclusivity of breastfeeding. We found no difference in nesfatin-1 levels between the two groups and no association with infant anthropometry, even after adjusting for potential confounders. However, high nesfatin-1 levels were correlated with low mBMI. Future research should investigate serum nesfatin-1 level in both mothers, infants and associations with growth in breastfed children.

Perinatal Cytomegalovirus Infection

PURPOSE OF REVIEW

There have been recent advances in the field of congenital CMV infection (cCMV) related to antiviral treatment of pregnant women and infants, the implementation of newborn CMV screening programs, and the frequency and diagnosis of complications among infected children. In addition, postnatal CMV infection (pCMV) is increasingly recognized as a potential cause of long-term sequelae in addition to acute complications among preterm infants, raising important questions related to treatment, and prevention.

RECENT FINDINGS

High-dose valacyclovir appears to be safe and effective for the prevention of cCMV among women with first-trimester primary CMV infection. New studies reveal high rates of vestibular dysfunction and neuropsychiatric manifestations among children with cCMV. Some studies report associations between pCMV and long-term consequences, including neurodevelopmental delay and bronchopulmonary dysplasia, among very low birth weight infants, in addition to high risk of sepsis and death acutely, which has motivated efforts to eliminate the virus from breast milk by different methods.

SUMMARY

More long-term complications of cCMV are increasingly recognized among children previously thought to be asymptomatic. Although a preventive CMV vaccine may be achievable, strategies to reduce the burden of cCMV disease include maternal education about risk-reduction behaviors, antiviral treatment of pregnant women with primary infection, and newborn screening to allow timely, appropriate care. Similarly, although it remains unclear if pCMV causes long-term problems, there is growing interest in identifying and preventing disease from CMV infections among preterm infants.

Comparison of Effects of Storage at Different Temperatures in a Refrigerator, Upright Freezer on Top of Refrigerator, and Deep Freezer on the Immunoglobulin A Concentration and Lysozyme Activity of Human Milk

This study aimed to investigate the effects of storing expressed human milk (HM) at different domestic storage temperatures on the secretory immunoglobulin A (SIgA) concentration and lysozyme activity. Forty mothers of full-term infants aged one to six months provided milk samples. The fresh samples were examined within 24 h of expression, and the other samples were stored in a refrigerator for four days or in two types of freezers for six months. The SIgA concentrations and lysozyme activity in the milk samples were studied using enzyme-linked immunosorbent assay (ELISA) kits and fluorometric lysozyme activity assay kits, respectively. The pairwise comparisons of the SIgA concentration and lysozyme activity were carried out using one-way analysis of variance with Dunnett T3 or Kruskal-Wallis tests with Bonferroni correction, depending on the data distribution. The mean temperatures of the refrigerator, upright freezer on top of the refrigerator, and deep freezer (chest freezer) were 2.0, -16.7, and -22.3 °C, respectively. Our study results highlight that the SIgA concentration and lysozyme activity of HM stored in the refrigerator for four days and in freezers for six months were significantly lower than those of fresh HM (p < 0.001). During the first six months of storage in both types of freezers, the SIgA levels were stable, whereas the lysozyme activity significantly decreased (p < 0.001). HM stored in the deep freezer had a higher SIgA concentration and lysozyme activity than HM stored in the upright freezer on top of the refrigerator. Our data support the superiority of fresh human milk over stored HM. If HM is to be stored, then storage in a deep freezer is potentially a more effective method for the preservation of SIgA concentrations and lysozyme activity than storage by refrigeration for four days or in an upright freezer on top of a refrigerator for six months.

Short-term effects of fresh mother's own milk in very preterm infants

Fresh mother's own milk (MOM) can protect preterm infants from many complications. Often MOM is pasteurized for safety, which can deactivate cellular and bioactive components with protective benefits. Questions remain regarding whether pasteurized MOM provides the same benefits as fresh MOM. The aim of this study was to evaluate the association and feasibility of feeding very preterm infants with fresh MOM. This prospective cohort study included 157 very preterm infants born before 32 weeks' gestational age and with a birthweight below 1500 g. Of these, 82 infants were included in the fresh MOM without any processing group and 75 infants were included in the pasteurized never-frozen MOM (PNFMOM) group. The mortality rate, survival rate without severe complication, incidence of complications, feeding indexes and growth velocities were compared to assess the association and feasibility of feeding fresh MOM. Compared with the PNFMOM group, the fresh MOM group had a higher survival rate without severe complications (p = 0.014) and a lower incidence of bronchopulmonary dysplasia (p = 0.010) after adjustment for confounders. The fresh MOM group regained birthweight earlier (p = 0.021), reached total enteral feeding earlier (p = 0.024), and received total parenteral nutrition for less time (p = 0.045). No adverse events associated with fresh MOM feeding were recorded. Feeding fresh MOM may reduce the incidence of complications in very premature infants. Fresh MOM was shown to be a feasible feeding strategy to improve preterm infants' outcomes.

Perspective: Human Milk Composition and Related Data for National Health and Nutrition Monitoring and Related Research

National health and nutrition monitoring is an important federal effort in the United States and Canada, and the basis for many of their nutrition and health policies. Understanding of child exposures through human milk (HM) remains out of reach due to lack of current and representative data on HM's composition and intake volume. This article provides an overview of the current national health and nutrition monitoring activities for HM-fed children, HM composition (HMC) and volume data used for exposure assessment, categories of potential measures in HM, and associated variability factors. In this Perspective, we advocate for a framework for collection and reporting of HMC data for national health and nutrition monitoring and programmatic needs, including a shared vision for a publicly available Human Milk Composition Data Repository (HMCD-R) to include essential metadata associated with HMC. HMCD-R can provide a central, integrated platform for researchers and public health officials for compiling, evaluating, and sharing HMC data. The compiled compositional and metadata in HMCD-R would provide pertinent measures of central tendency and variability and allow use of modeling techniques to approximate compositional profiles for subgroups, providing more accurate exposure assessments for purposes of monitoring and surveillance. HMC and related metadata could facilitate understanding the complexity and variability of HM composition, provide crucial data for assessment of infant and maternal nutritional needs, and inform public health policies, food and nutrition programs, and clinical practice guidelines.

Effects of the thawing rate and heating temperature on immunoglobulin A and lysozyme activity in human milk

Background

The percentage of infants receiving frozen human milk (HM) is increasing. The effects of thawing and warming on the secretory immunoglobulin A (SIgA) level and lysozyme activity in frozen HM should be investigated to identify optimal methods for preserving immune factors in frozen HM.

Methods

Milk samples were collected from 40 mothers with healthy full-term infants who had been lactating for one to six months. The baseline samples were analyzed within 24 h after collection, and the other samples were frozen at -18 °C before analyses. We compared two methods: placing the container overnight in a refrigerator at 4 °C before warming (slow thawing) and immediately thawing in warm water after removing the sample from the freezer (rapid thawing). Additionally, we investigated the effects of the warming temperature by comparing room temperature (25 °C) and physiological temperature (37 °C). The SIgA concentrations and lysozyme activities in the milk samples were determined using ELISA kits and fluorometric lysozyme activity assay kits, respectively.

Results

The SIgA concentrations and lysozyme activity in frozen HM were 16.5–52.1% and 16.8–39.3% lower than those in fresh HM, respectively. The SIgA concentrations in frozen HM were stable during slow thawing at 37 °C (p = 0.072) compared with those in fresh HM. The SIgA concentrations and lysozyme activity were maintained at significantly higher levels during slow thawing than during rapid thawing at 25 °C (p = 0.002 and p < 0.001, respectively). Slow thawing preserved higher SIgA concentrations and lysozyme activity than rapid thawing at 37 °C, but the difference was not significant.

Conclusions

The SIgA level in HM frozen at -18 °C for two months was stable after overnight thawing in the refrigerator (4 °C for 12 h) before warming to 37 °C compared with that in fresh milk. The thawing of HM in the refrigerator overnight (and then warming to 25 °C or 37 °C for 30 min) has the potential to preserve the SIgA concentration and lysozyme activity to a greater extent than heating immediately after removal from the freezer. Broader temperature ranges should be analyzed to determine the temperature that minimizes the losses in SIgA concentration and lysozyme activity in HM.

Natural Association of Lysozyme and Casein Micelles in Human Milk

Using reversed phase high-performance liquid chromatography with ultraviolet (UV) detection and electrospray ionization (ESI)-quadrupole time-of-flight mass spectrometry (RP-HPLC-UV-ESI-Q-TOF), the lysozyme content in the milk of 10 volunteering mothers was quantified, ranging from 29 to 96 μg/mL. Following ultracentifugation, it was found that the lysozyme in human milk, unlike other whey proteins, is mainly bound to casein micelles (ca. 75%). The enzymatic activity of human lysozyme, measured as lytic activity against cell walls of Micrococcus lysodeikticus, was similar for the micelle-bound and free protein, indicating that the micellar structure should not affect the antibacterial activity of lysozyme. The results indicate that lysozyme is an integral component of casein micelles in human milk.

Nutrients and Bioactive Components of Human Milk After One Year of Lactation: Implication for Human Milk Banks

OBJECTIVE

Specifying the nutrient content and bioactive compounds in milk from long-term lactation for the purpose of finding additional sources of donors' milk for human milk banks.

METHOD

Human milk samples were collected from 43 mothers of term infants (term infant human milk, TIHM) (3-6 weeks of lactation) and 50 mothers who have breastfed for over a year (long-nursing human milk, LNHM). The milk collection time was 24 hours. The analyses of fat, protein, carbohydrate and energy content were performed with human milk analyzer MIRIS (Miris HMA™ ); lactoferrin and vitamin C content using high performance liquid chromatography in reversed phase (RP-HPLC); total antioxidant activity (TAC) and lysozyme by enzyme-linked immunosorbent assay (ELISA); and the activity of glutathione peroxidase (GPx) and catalase (CAT) via spectrophotometric methods. Sociodemographic characteristics of both groups of mothers have been compiled.

RESULTS

Higher fat content and energy value was found in LNHM than in TIHM. Protein content in LNHM and TIHM did not differ. Carbohydrate content was lower in LNHM than in TIHM. TAC, CAT and GPx activity were higher in LNHM compared to TIHM. No significant differences in the content of lysozyme, lactoferrin and vitamin C between the studied groups were found.

CONCLUSIONS

The findings suggest that after 12 months of lactation, human milk still has significant nutritional value, does not lose bioactive components and can be considered for use in human milk banks.

Human Milk Metabolic Hormones: Analytical Methods and Current Understanding

Human milk (HM) contains a wide array of peptide hormones including leptin and adiponectin, which are involved in the regulation of infant growth and development. These essential hormones might play an important role in the regulation of metabolic reprogramming of the new-born infant. However, HM hormone studies are sparse and heterogeneous in regard to the study design, sample collection, preparation and analysis methods. This review discussed the limitations of HM hormone analysis highlighting the gaps in pre-analytical and analytical stages. The methods used to quantify HM metabolic hormones (leptin, adiponectin, ghrelin, insulin, obestatin, resistin and apelin) can be classified as immunoassay, immunosensor and chromatography. Immunoassay methods (ELISA and RIA) have been predominantly used in the measurement of these HM hormones. The relative validity parameters of HM hormones analysis are often overlooked in publications, despite the complexity and differences of HM matrix when compared to that of plasma and urine. Therefore, appropriate reports of validation parameters of methodology and instrumentation are crucial for accurate measurements and therefore better understanding of the HM metabolic hormones and their influences on infant outcomes.

Human milk triggers coagulation via tissue factor-exposing extracellular vesicles

Almost a century ago, it was discovered that human milk activates the coagulation system, but the milk component that triggers coagulation had until now been unidentified. In the present study, we identify this component and demonstrate that extracellular vesicles (EVs) present in normal human milk expose coagulant tissue factor (TF). This coagulant activity withstands digestive conditions, mimicking those of breastfed infants, but is sensitive to pasteurization of pooled donor milk, which is routinely used in neonatal intensive care units. In contrast to human milk, bovine milk, the basis of most infant formulas, lacks coagulant activity. Currently, the physiological function of TF-exposing vesicles in human milk is unknown, but we speculate that these vesicles may be protective for infants. Another explanation could be nipple skin damage, which occurs in most breastfeeding women. Milk-derived TF-exposing EVs may seal the wound and thereby reduce bleeding and breast inflammation.

A Comprehensive Analysis of Maternal and Newborn Disease and Related Control for COVID-19

The maternal-fetal/newborn unit is established at risk for COVID-19 infection. This narrative review summarizes the contemporary and cumulative publications which detail maternal infection, antenatal and newborn infections, and maternal/fetal/newborn management and prevention. There is a wide spectrum of maternal disease, but the potential for severe disease albeit in a minority is confirmed. COVID-19 carries risk for preterm delivery. Pregnant females can suffer multisystem disease, and co-morbidities play a significant role in risk. Congenital infection has been supported by several anecdotal reports, but strong confirmatory data are few. No typical congenital dysmorphisms are evident. Nevertheless, placental vascular compromise must be considered a risk for the fetus during advanced maternal infections. Clinical manifestations of newborn infection have been mild to moderate and relatively uncommon. Proven antiviral therapy is of yet lacking. The mode of delivery is a medical decision that must include patient risk assessment and patient directives. Both presymptomatic and asymptomatic mothers and offspring can complicate infection control management with the potential for spread to others in several regards. In the interim, infections of the maternal-fetal-newborn unit must be taken seriously both for the disease so caused and the potential for further dissemination of disease.

Concentrating human milk: an innovative point-of-care device designed to increase human milk feeding options for preterm infants

OBJECTIVE

The purpose of this study was to determine whether a point-of-care osmotic device concentrates important human milk (HM) nutrients to support feeding neonates requiring high-nutrient, low-volume feedings.

STUDY DESIGN

Raw and pasteurized HM samples were concentrated to determine the effects of time and temperature on concentration. Concentrated samples were compared with matched baseline samples to measure changes in selected nutrient concentrations. Furthermore, changes in concentration of certain bioactive components of raw milk samples were measured.

RESULT

The device significantly increased the concentrations of the majority of the measured nutrient and bioactive levels (p < 0.05). Increasing temperature of HM from 4 to 37 °C increased the concentration rate >30%. In all cases, the concentration rate of pasteurized HM was greater than that of raw HM.

CONCLUSIONS

The osmotic concentration of HM is a promising option for neonatal nutrition. Further studies are needed to establish an evidence base for the practical applications of this point-of-care device.

High-Temperature Short-Time and Holder Pasteurization of Donor Milk: Impact on Milk Composition

Holder pasteurization (HoP; 62.5 °C, 30 min) is commonly used to ensure the microbiological safety of donor human milk (DHM) but diminishes its nutritional properties. A high-temperature short-time (HTST) system was designed as an alternative for human milk banks. The objective of this study was to evaluate the effect of this HTST system on different nutrients and the bile salt stimulated lipase (BSSL) activity of DHM. DHM was processed in the HTST system and by standard HoP. Macronutrients were measured with a mid-infrared analyzer. Lactose, glucose, myo-inositol, vitamins and lipids were assayed using chromatographic techniques. BSSL activity was determined using a kit. The duration of HTST treatment had a greater influence on the nutrient composition of DHM than did the tested temperature. The lactose concentration and the percentage of phospholipids and PUFAs were higher in HTST-treated than in raw DHM, while the fat concentration and the percentage of monoacylglycerides and SFAs were lower. Other nutrients did not change after HTST processing. The retained BSSL activity was higher after short HTST treatment than that following HoP. Overall, HTST treatment resulted in better preservation of the nutritional quality of DHM than HoP because relevant thermosensitive components (phospholipids, PUFAs, and BSSL) were less affected.

Influence of feeding fresh colostrum from the dam or frozen colostrum from a pool on indicator gut microbes and the inflammatory response in neonatal calves

The aim of this study was to evaluate the capacity of cells from colostrum to modulate the intestinal microbial colonization, the activity of the inflammatory response, and for their influence on the development of diarrheal disease in calves. Twenty calves were distributed into two groups: COL+ (n = 10) receiving fresh whole colostrum; COL- (n = 10) receiving pooled frozen colostrum, containing no viable cells. All assessments were made before colostrum intake (D0), the next day (D2), and weekly on the 7th (D7), 14th (D14), 21st (D21) and 28th (D28) day of age. Diarrhea was assessed using a fecal score, and the systemic inflammatory status was assessed using a combination of temperature, anemia, total serum iron level, total haptoglobin concentration and the need for systemic antimicrobial treatment. The number of indicator bacteria present in the fecal population was estimated using qPCR. However, COL- calves presented more frequent signs of systemic inflammatory response including, fever at D7 (P = 0.011); indicator haptoglobin levels on D7 and D14, and lower levels of iron on D7, D14. Anemia was detected more often in the COL- calves on D21 (P = 0.043) and D28 (P = 0.016). COL- calves had a 1.66 greater chance of having elevated haptoglobin and a 1.8 greater chance of needing treatment with antimicrobials than COL+. A lower number of DNA copies of Clostridium perfringens were detected in COL+ calves on D2 (P = 0.088) and D7 (P = 0.040). Similarly, a low number of DNA copies was observed for Escherichia coli and Lactobacillus spp. (P = 0.012) in the fecal samples of COL+ calves on D7.

The Effect of Prolonged Freezing and Holder Pasteurization on the Macronutrient and Bioactive Protein Compositions of Human Milk

Introduction: Human donor milk is widely used to feed premature and sick newborns when the milk of their own mothers is insufficient. All treatment processes involving human milk affect its composition. The aim of this study was to assess changes in the macronutrients and bioactive protein (lactoferrin and lysozyme) content in human milk caused by freezing and Holder pasteurization. Materials and Methods: Milk samples were collected from 42 mothers 14-16 days after delivery. Each sample was divided into two parts and tested twice for macronutrient content, once upon being freshly collected and again after freezing at -40°C, thawing and Holder pasteurization. The lysozyme and lactoferrin concentrations were first determined in the unpasteurized thawed human milk after it was stored frozen at -80°C for up to 10 months and again after Holder pasteurization. The macronutrient concentrations were determined by midinfrared spectrophotometry, and enzyme-linked immunosorbent assay was used to measure the lysozyme and lactoferrin concentrations. Results: Freezing and Holder pasteurization had no significant effects on the macronutrient concentrations. The mean lactoferrin content before and after pasteurization was 2.5 ± 1.07 and 0.03 ± 0.03 mg/mL, respectively (p < 0.001), and the lysozyme content was 19.57 ± 20.11 and 12.62 ± 14.14 μg/mL, respectively (p = 0.007). Conclusions: Freezing and Holder pasteurization did not decrease the nutritional value of human milk but caused considerable loss of lactoferrin and lysozyme. New methods for treating human milk are needed that ensure the destruction of pathogenic microorganisms while retaining the biological and nutritional value of the milk. The Clinical Trial Registration number: NCT04382989.

The Effect of Processing Donor Milk on Its Nutrient and Energy Content

Background: The pasteurization is a mandatory step to inactivate pathogenic microorganisms of bank milk. For storage, freezing and thawing are necessary. The concentration of macronutrients and energy of bank milk could be influenced by these procedures which are routinely used in human milk bank. Research Aim: The aim of this study is to analyze the effect of bank milk processing (pasteurization and freezing/thawing) on the macronutrients (fat, protein, and carbohydrate) concentration and energy content. Materials and Methods: The samples of donor milk were collected and studied before/after pasteurization and after frozen for 3 months. Total 100 samples of bank milk were tested using an infrared analyzer. The measurements of fat, protein, carbohydrate, and energy were statistically analyzed by SPSS. Results: There was a prominent reduction of fat mean concentration following pasteurization and frozen (20.5% and 6.5%, respectively). The processing did not cause significant changes in protein content, but there were significant increase after pasteurization and decrease after frozen in carbohydrate (p < 0.05). Overall (postpasteurization and frozen storage), a 9.6% decrease was observed for energy content. Conclusion: This study revealed that the processing of bank milk (including Holder Pasteurization and frozen storage) decreased fat and energy content of human milk significantly, and this could not meet the specific needs of preterm infants.

Biological activities of commercial bovine lactoferrin sources

Lactoferrin (Lf) samples from several manufacturers were evaluated in vitro. The purity and protein form of each Lf were examined by SDS-PAGE, Western blot, and proteomics analysis. Assays were conducted to evaluate uptake of Lfs and iron from Lfs by enterocytes as well as Lf bioactivities, including effects on intestinal cell proliferation and differentiation, IL-18 secretion, TGF-β1 transcription, and growth of enteropathogenic Escherichia coli (EPEC). Composition of the Lfs varies; some only contain a major Lf band (∼80 kDa), and some also contain minor forms. All Lfs and iron from the Lfs were absorbed by Caco-2 cells, with various efficiencies. The bioactivities of the Lfs varied considerably, but there was no consistent trend. All Lfs promoted intestinal cell proliferation, secretion of IL-18, and transcription of TGF-β1. Some Lfs exhibited pro-differentiation effects on Caco-2 cells. Effects of pasteurization (62.5 °C for 30 min, 72 °C for 15 s, or 121 °C for 5 min) on integrity, uptake, and bioactivities were examined using Dicofarm, Tatua, and native bovine Lfs. Results show that pasteurization did not affect protein integrity, but variously affected uptake of Lf and its effects on intestinal proliferation, differentiation, and EPEC growth. To choose a Lf source for a clinical trial, assessment of bioactivities is recommended.

Cytokine Expression by Human Macrophage-Like Cells Derived from the Monocytic Cell Line THP-1 Differs Between Treatment With Milk from Preterm- and Term-Delivering Mothers and Pasteurized Donor Milk

Immunomodulatory proteins from human milk may enhance the protection and development of the infant’s gut. This study compared the immunomodulatory effects of treatment with milk from preterm-(PM) and term-delivering (TM) mothers and pasteurized donor milk (DM) on cytokine gene expression in human macrophage-like cells derived from the monocytic cell line THP-1. The gene expression of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-12 (p40), IL-10 and GAPDH in macrophages treated with PM, TM and DM at steady and activated (inflammatory) states were measured using real-time reverse transcription-polymerase chain reaction. TNF-α and IL-6 in macrophages (both states) with DM were higher than PM or TM. IL-10 in steady state macrophages with DM was higher than PM whereas DM increased IL-10 in activated macrophages compared with TM. TM increased IL-6 and IL-12 (p40) in steady state macrophages compared with PM. IL-12 (p40) in activated macrophages with TM was higher than PM. IL-10 in steady state macrophages with TM was higher than PM. These results suggest that DM induces higher gene expression of pro-inflammatory and anti-inflammatory cytokines in macrophages compared with PM or TM. PM reduced gene expression of pro-inflammatory cytokines compared with TM, which may decrease the development of necrotizing enterocolitis and systematic inflammation.

A randomized controlled trial protocol comparing the feeds of fresh versus frozen mother's own milk for preterm infants in the NICU

Background

Necrotizing enterocolitis (NEC) is the leading cause of death among preterm infants born at < 30 weeks’ gestation. The incidence of NEC is reduced when infants are fed human milk. However, in many neonatal intensive care units (NICUs), it is standard practice to freeze and/or pasteurize human milk, which deactivates bioactive components that may offer additional protective benefits. Indeed, our pilot study showed that one feed of fresh mother’s own milk per day was safe, feasible, and can reduce morbidity in preterm infants. To further evaluate the benefits of fresh human milk in the NICU, a randomized controlled trial is needed.

Methods

Our prospective multicenter, double-blinded, randomized, controlled trial will include infants born at < 30 weeks’ gestation and admitted to one of 29 tertiary NICUs in China. Infants in the intervention (fresh human milk) group (n = 1549) will receive at least two feeds of fresh human milk (i.e., within 4 h of expression) per day from the time of enrollment until 32 weeks’ corrected age or discharge to home. Infants in the control group (n = 1549) will receive previously frozen human milk following the current standard protocols. Following informed consent, enrolled infants will be randomly allocated to the control or fresh human milk groups. The primary outcome is the composite outcome mortality or NEC ≥ stage 2 at 32 weeks’ corrected age, and the secondary outcomes are mortality, NEC ≥ stage 2, NEC needing surgery, late-onset sepsis, retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD), weight gain, change in weight, increase in length, increase in head circumference, time to full enteral feeds, and finally, the number and type of critical incident reports, including feeding errors.

Discussion

Our double-blinded, randomized, controlled trial aims to examine whether fresh human milk can improve infant outcomes. The results of this study will impact both Chinese and international medical practice and feeding policy for preterm infants. In addition, data from our study will inform changes in health policy in NICUs across China, such that mothers are encouraged to enter the NICU and express fresh milk for their infants.

Trial registration

Chinese Clinical Trial Registry; #ChiCTR1900020577; registered January 1, 2019; http://www.chictr.org.cn/showprojen.aspx?proj=34276

Impact of vaccination during pregnancy and staphylococci concentration on the presence of Bacillus cereus in raw human milk

OBJECTIVE

This study aimed to determine whether vaccination during pregnancy, prematurity, and staphylococci concentration influenced the presence of B. cereus or staphylococcal enterotoxins (SEs) in raw human milk from healthy mothers.

STUDY DESIGN

Human milk samples were collected from 152 healthy women. B. cereus, S. aureus and coagulase-negative staphylococci (CNS) were enumerated using selective agar culture media. The detection of B. cereus spores and SEs were determined using ELISA.

RESULTS

CNS and B. cereus concentrations in milk from non-vaccinated mothers were higher than that from mothers vaccinated during pregnancy, but S. aureus did not differ. Prematurity did not affect B. cereus or staphylococci in human milk. S. aureus and CNS concentrations in human milk with the presence of B. cereus were higher than that with the absence of B. cereus. Viable B. cereus was present in 9.2% of raw human milk samples whereas SEs were not detected in any samples.

CONCLUSIONS

Vaccination during pregnancy and low concentration of staphylococci could reduce the risk of B. cereus in raw human milk. The screening of B. cereus in raw human milk must be performed before pasteurization to reduce the risk of B. cereus infection in preterm infants.

Modulation activity of heat-treated and untreated lactoferrin on the TLR-4 pathway in anoxia cell model and cerebral ischemia reperfusion mouse model

This study aimed to investigate the modulation activity of heated and nonheated lactoferrins in an inflammatory pathway in anoxia and reoxygenation cell and cerebral ischemic reperfusion mouse models. Rat pheochromocytoma 12 (PC-12) cells were subjected to oxygen and glucose deprivation in vitro to construct an anoxia and reoxygenation cell model, and Institute for Cancer Research (ICR) mice were given carotid artery "ligation-relaxation" in vivo to construct a cerebral ischemic reperfusion mouse model. The protein levels of toll-like receptor 4 (TLR-4) and downstream inflammatory proteins including nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α), and IL-1β were detected. Meanwhile, metabonomic detection of overall metabolites of PC-12 cells was performed to screen out the specific changed metabolite affected by lactoferrin at the condition of anoxia and reoxygenation. The results showed that lactoferrin could inhibit the TLR-4-related pathway triggered by anoxia and reoxygenation and ischemic reperfusion. A total of 41 significantly changed metabolites were identified by metabonomic analysis, and glutathione was seen as a metabolite of interest in suppressing TLR-4-related pathway in anoxia and reoxygenation cell models. However, heated lactoferrin lost the ability of attenuating the TLR-4-related pathway. The loss of modulation activity of heated lactoferrin might be due to its protein aggregation, which was evidenced by larger average particle diameter than the unheated lactoferrin. This study is the first to investigate the effect of heat treatment on the modulation activity of lactoferrin in the TLR-4-related pathway in anoxia and reoxygenation cell and cerebral ischemic reperfusion mouse models, and indicate that lactoferrin may serve as a dietary intervention for cerebral ischemia.

Differences in Current Procedures for Handling of Expressed Mother's Milk in Danish Neonatal Care Units

BACKGROUND

Mother's own milk (MOM) is preferred when feeding preterm infants. When expressed mother's milk is stored and handled, there is a risk of bacterial contamination, decreased immunological activity, and less nutritional potential.

PURPOSE

The aim of this study was to investigate current routines when handling MOM in Danish neonatal intensive care units (NICUs).

METHODS

A survey was sent to all 17 NICUs in Denmark in which current practices regarding human milk handling, storage, and preparation were evaluated. Furthermore, one question sought to establish when mother's milk was believed to be colostrum. Respondents of the survey were neonatal nurses.

RESULTS

All 17 units responded to the survey. Only 5 of 17 units answered that human colostrum was defined as milk from the first week after birth. Refrigerator storage time varied between 24 and 72 hours. In 6 of 17 units, parents were in charge of mixing milk and fortifier. Heating of human milk was done by using microwave ovens in 4 of 17 of the units.

IMPLICATIONS FOR PRACTICE

This national survey established that there is significant variability in the way mother's milk is handled. Some of the procedures performed may affect the quality of the milk. It is important to implement evidence-based practice regarding storage and handling of expressed mother's milk to ensure that the quality of the milk is the best possible alternative for all preterm infants.

IMPLICATIONS FOR RESEARCH

Prospective studies are needed to examine the association between handling of human milk and changes in composition and nutritional potential of the milk.

Current Trends in Research on Human Milk Exchange for Infant Feeding

Breastfeeding is critical for the healthy growth and development of infants. A diverse range of infant-feeding methods are used around the world today. Many methods involve feeding infants with expressed human milk obtained through human milk exchange. Human milk exchange includes human milk banking, human milk sharing, and markets in which human milk may be purchased or sold by individuals or commercial entities. In this review, we examine peer-reviewed scholarly literature pertaining to human milk exchange in the social sciences and basic human milk sciences. We also examine current position and policy statements for human milk sharing. Our review highlights areas in need of future research. This review is a valuable resource for healthcare professionals and others who provide evidence-based care to families about infant feeding.

Human T-Cell Lymphotropic Virus Type 1 and associated diseases in Latin America

This narrative review, which is based on a systematic literature search following the PRISMA guidelines, provides a general overview of Human T-cell Lymphotropic Virus type 1 (HTLV-1) and associated diseases: Adult T-cell Leukaemia-Lymphoma (ATLL) and HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) in Latin America, focusing on epidemiology and prevention. Using the published information on HTLV-1, ATLL and HAM/TSP prevalence, we present comprehensive and accurate maps and tables, and developed an algorithm to assist in the prevention of HTLV-1 transmission through breastfeeding while considering socio-economic status. Latin America is an interesting scenario to study HTLV-1 because of the diverse origin of its population. Apart from the expected high prevalence in inhabitants of African ancestry, the presence of endemic foci affecting indigenous populations is particularly striking. ATLL prevention is the biggest challenge in this field. Most ATLL cases are transmitted through breastfeeding; thus, prevention methods to avoid ATLL in endemic countries have to be focused on this. In view of the high inequality in most Latin American countries, reduction in breastfeeding duration, freezing/thawing and pasteurisation of breastmilk can be suitable interventions in poor settings, considering that avoiding the risk of malnutrition and infant mortality must be the priority.

Impact of human milk on the transcriptomic response of fetal intestinal epithelial cells reveals expression changes of immune-related genes

Human milk, the best food for infants, is a dynamic and complex fluid that directly influences the immune system and microbiota establishment.

Human milk, the best food for infants, is a dynamic and complex fluid that directly influences the immune system and microbiota establishment. The protective role of human milk is well known although the mechanisms behind it still need to be uncovered. This study aimed to characterize the impact of human milk in the immature intestine of newborns by analyzing the global transcriptomic response of the FHs 74 int cell line (ATCC CCL-241). The expression of intestinal keratins and other genes with a well-annotated intestinal or epithelial function validated FHs 74 int derived from the fetal small intestine as a model of the intestinal epithelium of newborns. Cells exposed to skimmed human milk showed seventeen differentially expressed genes, most of them up-regulated, including four chemokine genes (CXCL1, CXCL2, CXCL3 and CXCL10) and other immune-related genes. qRT-PCR and ELISA analysis confirmed the microarray data and indicated a different pattern of expression upon milk exposure in FHs 74 int as compared to the adult tumorigenic Caco-2 cell line. The evaluation of the functional significance of these transcriptomic changes reveals that human milk exposure may contribute to the regulation of the inflammatory response in the intestine during the perinatal period, which is characterized by the immaturity of the immune system and a pro-inflammatory phenotype.

Testing the feasibility and safety of feeding preterm infants fresh mother's own milk in the NICU: A pilot study

Necrotizing enterocolitis (NEC) is the leading cause of death among infants born at <30 weeks’ gestation, but donor human milk can reduce the incidence of NEC. Unfortunately, freezing or pasteurizing human milk deactivates beneficial bioactive components. We evaluated the feasibility, safety, and impact of feeding very preterm infants fresh (unprocessed) mother’s own milk within 4 hours of expression. In our multicentre prospective cohort analytic study, we fed 109 control and 98 intervention infants previously frozen donor or mother’s own milk; only the intervention group was fed fresh mother’s own milk once daily from enrollment until 32 weeks’ corrected age. Control group mothers could not commit to provide fresh milk daily and were less likely receive antenatal corticosteroids than mothers in the intervention group. In the intervention group, 87.5% (98/112) of mothers were able to provide at least one feed of fresh milk a day. No critical incidents or non-compliance with the protocol were reported. The duration of mechanical ventilation and total parenteral nutrition use were shorter in the intervention group than controls (P < 0.01) but the length of hospital stay was similar (P = 0.57). Although the study might be underpowered, the intervention group had lower unadjusted rates of the composite outcome NEC ≥ stage 2 or mortality (8% vs 20%, P = 0.04), sepsis (22% vs 38%, P = 0.02), retinopathy of prematurity (17% vs 39%, P < 0.01) and bronchopulmonary dysplasia (32% vs 47%, P < 0.01) than the control. These results indicated that feeding fresh mother’s own milk once daily was safe, feasible, and may reduce morbidity.

Effect of Heat Treatment on the Antitumor Activity of Lactoferrin in Human Colon Tumor (HT29) Model

To investigate the effect of heat treatment on the antitumor activity of lactoferrin in colon cancer cells and colon tumors, the HT-29 (human intestinal epithelial tumor cell) cell line was exposed to lactoferrin and various heat treatments. The impacts on cell proliferation, invasion, and migration were observed in vitro, and nude mice bearing HT29 tumors were administered lactoferrin and underwent various heat treatments in vivo. In the HT29 cell proliferation test using transwell and scratch analyses, lactoferrin (20 mg/mL) without or with heat treatment (50 and 70 °C) significantly inhibited cell proliferation, migration, and invasion (compared with the control, p < 0.05), while lactoferrin with heat treatment (100 °C) did not affect these parameters. In vivo, HT29 tumor weight was significantly reduced in the lactoferrin (without heat treatment and with 50 and 70 °C treatment) groups (1.59 ± 0.20, 1.67 ± 0.25, and 2.41 ± 0.42 g, compared with the control, p < 0.05), and there was no significant difference between the control (3.73 ± 0.33 g) and the 100 °C treatment group (3.58 ± 0.29 g). Moreover, 100 °C heat treatment reduced inhibition of the VEGFR2/VEGFA/PI3K/Akt/Erk1/2 angiogenesis pathway by lactoferrin. In summary, HT29 tumors were effectively suppressed by lactoferrin via inhibition of VEGFR2/VEGFA/PI3K/Akt/Erk1/2 pathway, and heat treatment affected the antitumor activity of lactoferrin in a temperature-dependent manner.

Infant Feeding and Weight Gain: Separating Breast Milk From Breastfeeding and Formula From Food

OBJECTIVES

Studies addressing breastfeeding and obesity rarely document the method of breast milk feeding, type of supplementation, or feeding in hospital. We investigated these practices in the CHILD birth cohort.

METHODS

Feeding was reported by mothers and documented from hospital records. Weight and BMI z scores (BMIzs) were measured at 12 months. Analyses controlled for maternal BMI and other confounders.

RESULTS

Among 2553 mother-infant dyads, 97% initiated breastfeeding, and the median breastfeeding duration was 11.0 months. Most infants (74%) received solids before 6 months. Among "exclusively breastfed" infants, 55% received some expressed breast milk, and 27% briefly received formula in hospital. Compared with exclusive direct breastfeeding at 3 months, all other feeding styles were associated with higher BMIzs: adjusted β: +.12 (95% confidence interval [CI]: .01 to .23) for some expressed milk, +.28 (95% CI: .16 to .39) for partial breastfeeding, and +.45 (95% CI: .30 to .59) for exclusive formula feeding. Brief formula supplementation in hospital did not alter these associations so long as exclusive breastfeeding was established and sustained for at least 3 months. Formula supplementation by 6 months was associated with higher BMIzs (adjusted β: +.25; 95% CI: .13 to .38), whereas supplementation with solid foods was not. Results were similar for weight gain velocity.

CONCLUSIONS

Breastfeeding is inversely associated with weight gain velocity and BMI. These associations are dose dependent, partially diminished when breast milk is fed from a bottle, and substantially weakened by formula supplementation after the neonatal period.

Best Practices for Handling and Administration of Expressed Human Milk and Donor Human Milk for Hospitalized Preterm Infants

The importance of human milk for the preterm infant is well established (1-3). However, the feeding of human milk to preterm infants is typically much more complicated than the mere act of breastfeeding (3, 4). The limited oral feeding skills of many preterm infants often results in human milk being administered via an enteral feeding tube (4). In addition, fortification is commonly required to promote optimal growth and development-particularly in the smallest of preterm infants (2, 4, 5). Consequently, a mother's own milk must be pumped, labeled, transported to the hospital, stored, tracked for appropriate expiration dates and times, thawed (if previously frozen), fortified, and administered to the infant with care taken at each step of the process to avoid microbial contamination, misadministration (the wrong milk for the wrong patient), fortification errors, and waste (1-5). Furthermore, the use of pasteurized donor human milk (DHM) for preterm infants when a mother's own milk is not available has been endorsed by many organizations (1). Therefore, appropriate procurement, storage, thawing (if received frozen), fortification, labeling, and administration must occur with the same considerations of preventing contamination and fortification errors while ensuring the correctly prepared final product reaches the correct patient (1). Many professional organizations have published best practices to provide hospitals with guidelines for the safe and accurate handling and preparation of expressed human milk (EHM) and DHM feedings for preterm infants (1-5). These best practices emphasize the importance of preparation location, trained staff, proper identification of human milk to prevent misadministration, and strategies to prevent fortification errors (1-6). The purpose of this mini-review article is to summarize current published best practices for the handling of human milk for preterm infants within the hospital setting (1-6). Emphasis will focus on the use of aseptic technique with proper sanitation and holding times/temperatures to limit microbial growth; use of technology to prevent misadministration of human milk and fortification errors as well as for tracking of expiration dates/times and lot numbers; and workflow strategies to promote safety while improving efficiencies (1-7).

Effects of Refrigerated and Frozen Storage on Holder-Pasteurized Donor Human Milk: A Systematic Review

BACKGROUND

Pasteurized donor human milk (PDHM) is the recommended feeding alternative for preterm infants when mother's own milk is not available. Use of PDHM in United States neonatal hospitals is increasing, although guidelines for the refrigerated and frozen storage are limited.

OBJECTIVE

We aimed to review the current evidence for the storage of Holder PDHM (HPDHM) under refrigerated and frozen storage conditions.

METHODS

A systematic review of the literature was conducted for studies published between 1985 and May 2018. Studies were included if they studied the storage of Holder-pasteurized human milk under refrigerated or frozen storage conditions.

RESULTS

Fourteen studies met the inclusion criteria. Five studies addressed refrigerated storage and nine studies addressed frozen storage. There was little overlap in the outcomes measured or the analytical methods employed. There was concordance in three studies reporting no microbial growth over 4-9 days of refrigerated storage, and in five studies reporting a reduction in fat during 1-8 months of frozen storage. Only one study assessed the storage of HPDHM that had been fortified.

CONCLUSIONS

Long-term refrigerated and frozen storage of HPDHM affects some components in milk more than others. While there is evidence of microbial purity during four or more days of refrigerated storage in clinical conditions, there is limited research on the impact of macro and micronutrients, or the impact of fortifiers. More research is needed in these areas.

Pro-inflammatory cytokines and growth factors in human milk: an exploratory analysis of racial differences to inform breast cancer etiology

BACKGROUND

Analysis of cytokines and growth factors in human milk offers a noninvasive approach for studying the microenvironment of the postpartum breast, which may better reflect tissue levels than testing blood samples. Given that Black women have a higher incidence of early-onset breast cancers than White women, we hypothesized that milk of the former contains higher levels of pro-inflammatory cytokines, adipokines, and growth factors.

METHODS

Participants included 130 Black and 162 White women without a history of a breast biopsy who completed a health assessment questionnaire and donated milk for research. Concentrations of 15 analytes in milk were examined using two multiplex and 4 single-analyte electrochemiluminescent sandwich assays to measure pro-inflammatory cytokines, angiogenesis factors, and adipokines. Mixed-effects ordinal logistic regression was used to identify determinants of analyte levels and to compare results by race, with adjustment for confounders. Factor analysis was used to examine covariation among analytes.

RESULTS

Thirteen of 15 analytes were detected in ≥ 25% of the human milk specimens. In multivariable models, elevated BMI was significantly associated with increased concentrations of 5 cytokines: IL-1β, bFGF, FASL, EGF, and leptin (all p-trend < 0.05). Black women had significantly higher levels of leptin and IL-1β, controlling for BMI. Factor analysis of analyte levels identified two factors related to inflammation and growth factor pathways.

CONCLUSION

This exploratory study demonstrated the feasibility of measuring pro-inflammatory cytokines, adipokines, and angiogenesis factors in human milk, and revealed higher levels of some pro-inflammatory factors, as well as increased leptin levels, among Black as compared with White women.

Adipokines in human breast milk

The review describes the molecular characteristics of so far detected breast milk adipokines and ranks their breast milk level compared to the respective levels in maternal and infant blood. Moreover, analytical knowledge for measurements of breast milk adipokines will be delineated. Next, we summarized data about two main potential influencing factors on adipokine concentration in breast milk, maternal weight and pasteurization of milk. Finally, associations between adipokines in breast milk and weight gain in infants as well as the putative mechanisms for effects of breast milk adipokines on food intake and weight gain in later life will debated. Our findings suggest that a source of adipokines in human breast milk cannot be uniformly defined. In dependence on the ratio between serum and breast milk levels the major quantity of these proteins may be derived from peripheral tissues, from the breast tissue itself or from both. Thus, leptin and in part adiponectin levels in breast milk are dependent on a plenty of influencing factors with an important relevance of maternal anthropometric characteristics There is some evidence that leptin, adiponectin and ghrelin levels in breast milk may be associated with growth gain of infants and even with increased risk for being overweight during infancy or childhood. We hypothesize that a dysregulation in adipokine homeostasis in early life could promote obesity and metabolic disturbance in later life.

Effect of HTST and Holder Pasteurization on the Concentration of Immunoglobulins, Growth Factors, and Hormones in Donor Human Milk

Donor human milk (DHM) is submitted to Holder pasteurization (HoP) to ensure its microbiological safety in human milk banks but this treatment affects some of its bioactive compounds. The objective of this work was to compare the effects of HoP and high temperature short time (HTST) treatments on some bioactive compounds found in DHM. A total of 24 DHM batches were processed in a continuous HTST system (70, 72, and 75°C for 5-25 s) and by HoP (62.5°C for 30 min). The concentrations of immunoglobulins (Igs) A, G, and M, transforming growth factor-beta 2 (TGF-β₂), adiponectine, ghrelin, and leptin were measured using a multiplex system, whereas the concentration of epidermal growth factor (EGF) was determined by ELISA. In relation to Igs, IgG showed the highest preservation rates (87-101%) after HTST treatments, followed by IgA (54-88%) and IgM (25-73%). Ig retention after any of the HTST treatments was higher than after HoP (p < 0.001). Treatment times required to reduce the concentration of IgM by 90% (D-value) were 130, 88, and 49 s at 70, 72, and 75°C, while the number of degrees Celsius required to change the D-value by one factor of 10 (z-value) was 11.79°C. None of the heat treatments had a significant effect on the concentrations of TGF-β₂, EGF, adiponectin, and ghrelin. In contrast, leptin was detected only in 4 of the samples submitted to HoP, whereas it was present in all samples after the different HTST treatments, with retention rates ranging between 34 and 68%. Globally, the concentration of IgA, IgG, IgM, and leptin in DHM was significantly higher after HTST pasteurization performed in a continuous system designed to be used in human milk banks than after the HoP procedure that is routinely applied at present.

Effect of the Various Steps in the Processing of Human Milk in the Concentrations of IgA, IgM, and Lactoferrin

INTRODUCTION

Human milk immune components are unique and important for the development of the newborn. Milk processing at the Human Milk Banks (HMB), however, causes partial destruction of immune proteins. The objective of this study was to determine the effects that heating during the milk processing procedure at the HMB had on the concentrations of IgA, IgM, and lactoferrin at three critical points in time.

MATERIALS AND METHODS

Fifty milk samples (150 mL) were collected from voluntary donors at the HMB at the Hospital Nacional Pedro de Bethancourt, located in Antigua Guatemala. Samples from three critical points in time during the milk processing procedure were selected for analysis: freezing/thawing I, freezing/thawing II, and pasteurization. IgA, IgM, and lactoferrin concentrations were determined during each critical point and compared with a baseline concentration.

RESULTS

After milk processing, IgA, IgM, and lactoferrin mean concentrations were reduced by 30.0%, 36.0%, and 70.0%, respectively (p < 0.001). Reduction of biological activity was mainly attributed to pasteurization for IgA and lactoferrin (p < 0.001); the first freezing/thawing processes before pasteurization showed no significant reduction difference between mean concentrations of IgA (p = 0.160) and lactoferrin (p = 0.345) but showed a significant effect on IgM concentration (p = 0.016), and the second freezing/thawing procedure only showed a significant effect on IgA (p < 0.001).

CONCLUSIONS

The effects of milk processing on the immune proteins that were evaluated in this study demonstrated a significant reduction.

Human Milk Processing: A Systematic Review of Innovative Techniques to Ensure the Safety and Quality of Donor Milk

Pasteurization, performed at 62.5°C for 30 minutes (holder pasteurization), is currently recommended in all international human milk banks guidelines, but it affects some human milk bioactive and nutritive components. The present systematic review is aimed at critically reviewing evidence on the suitability of human milk processing techniques other than holder pasteurization, both thermal and nonthermal, to ensure microbiological safety, and on the effects of these techniques on biologically active donor milk components. A systematic review of English and non-English articles using Medline, PubMed, Embase, SCOPUS, and CAB Abstracts, with no restriction in publication date was performed. Search terms included: human, breast, donor, or banked milk, breastmilk, breast fed, breastfed, breastfeed; HTST, Flash, High Pressure, UV, ultrasonic or nonthermal; process, pasteuris, pasteuriz. Only primary research articles published in peer-reviewed journals were included, providing or not a comparison with holder pasteurized human milk, provided that the pasteurization technique was clearly described, and not intended for domestic use. Additional studies were identified by searching bibliographies of relevant articles. Twenty-six studies were identified as being relevant. Two examined both High Pressure Processing and High-Temperature-Short-Time pasteurization; 10 only examined High Pressure Processing; 10 only examined High-Temperature-Short-Time; 2 articles examined ultraviolet irradiation; 2 articles examined (thermo-)ultrasonic processing. The results indicate that data about safety for microbiological control are still scarce for most of the novel technologies, and that consensus on processing conditions is necessary for nonthermal technologies, before any conclusions on the qualitative and nutritional advantages of these techniques can be drawn.

Human Milk-Treatment and Quality of Banked Human Milk

The aim of human milk banks is to deliver safe and high quality donor human milk. Treatment of human milk has to destroy most microorganisms while preserving immunological and nutrient components, which is obtained when using low time low temperature pasteurization. However it destroys bile-simulated lipase, reduces lactoferrin, lysozyme, immunoglobulins, and bactericidal capacity of human milk. New methods are under investigation such as high temperature short time pasteurization, high pressure processing, or ultraviolet irradiation. They have been tested in experimental conditions and there are promising results, but they have to be tested in real conditions in human milk bank.