High-Temperature Short-Time Pasteurization System for Donor Milk in a Human Milk Bank Setting

Personalized Nutrition with Banked Human Milk for Early Gut Microbiota Development: In Pursuit of the Perfect Match

The correct initial colonization and establishment of the gut microbiota during the early stages of life is a key step, with long-lasting consequences throughout the entire lifespan of the individual. This process is affected by several perinatal factors; among them, feeding mode is known to have a critical role. Breastfeeding is the optimal nutrition for neonates; however, it is not always possible, especially in cases of prematurity or early pathology. In such cases, most commonly babies are fed with infant formulas in spite of the official nutritional and health international organizations' recommendation on the use of donated human milk through milk banks for these cases. However, donated human milk still does not totally match maternal milk in terms of infant growth and gut microbiota development. The present review summarizes the practices of milk banks and hospitals regarding donated human milk, its safety and quality, and the health outcomes in infants fed with donated human milk. Additionally, we explore different alternatives to customize pasteurized donated human milk with the aim of finding the perfect match between each baby and banked milk for promoting the establishment of a beneficial gut microbiota from the early stages of life.

Clinical Impact of Supplementation with Pasteurized Donor Human Milk by High-Temperature Short-Time Method versus Holder Method in Extremely Low Birth Weight Infants: A Multicentre Randomized Controlled Trial

Nosocomial infections are a frequent and serious problem in extremely low birth weight (ELBW) infants. Donor human milk (DHM) is the best alternative for feeding these babies when mother's own milk (MOM) is not available. Recently, a patented prototype of a High-Temperature Short-Time (HTST) pasteurizer adapted to a human milk bank setting showed a lesser impact on immunologic components. We designed a multicentre randomized controlled trial that investigates whether, in ELBW infants with an insufficient MOM supply, the administration of HTST pasteurized DHM reduces the incidence of confirmed catheter-associated sepsis compared to DHM pasteurized with the Holder method. From birth until 34 weeks postmenstrual age, patients included in the study received DHM, as a supplement, pasteurized by the Holder or HTST method. A total of 213 patients were randomized; 79 (HTST group) and 81 (Holder group) were included in the analysis. We found no difference in the frequency of nosocomial sepsis between the patients of the two methods-41.8% (33/79) of HTST group patients versus 45.7% (37/81) of Holder group patients, relative risk 0.91 (0.64-1.3), p = 0.62. In conclusion, when MOM is not available, supplementing during admission with DHM pasteurized by the HTST versus Holder method might not have an impact on the incidence of catheter-associated sepsis.

Breast milk preservation: thermal and non-thermal processes and their effect on microorganism inactivation and the content of bioactive and nutritional compounds

Human Breast Milk (HBM) is widely acknowledged as the best nutritional source for neonates. Data indicates that, in 2019, 83.2% of infants in the United States received breast milk at birth, slightly reducing to 78.6% at 1 month. Despite these encouraging early figures, exclusive breastfeeding rates sharply declined, dropping to 24.9% by 6 months. This decline is particularly pronounced when direct breastfeeding is challenging, such as in Neonatal Intensive Care Units (NICU) and for working mothers. Given this, it is vital to explore alternative breast milk preservation methods. Technologies like Holder Pasteurization (HoP), High-Temperature Short-Time Pasteurization (HTST), High-Pressure Processing (HPP), UV radiation (UV), and Electric Pulses (PEF) have been introduced to conserve HBM. This review aims to enhance the understanding of preservation techniques for HBM, supporting the practice of extended exclusive breastfeeding. It explicitly addresses microbial concerns, focusing on critical pathogens like Staphylococcus aureus, Enterococcus, Escherichia coli, Listeria monocytogenes, and Cytomegalovirus, and explores how various preservation methods can mitigate these risks. Additionally, the review highlights the importance of retaining the functional elements of HBM, particularly its immunological components such as antibodies and enzymes like lysozyme and Bile Salt Stimulated Lipase (BSSL). The goal is to provide a comprehensive overview of the current state of HBM treatment, critically assess existing practices, identify areas needing improvement, and advocate for extended exclusive breastfeeding due to its vital role in ensuring optimal nutrition and overall health in infants.

Comparative analyses of holder pasteurization vs. HTST pasteurization for donor milk: a cost-minimization study applicable to human milk banks

BACKGROUND

High-temperature short-time (HTST) pasteurization (72-75 °C, 15 s) is an alternative treatment to traditional Holder pasteurization (HoP) (62ºC, 30 min) for donor milk. HTST pasteurization guarantees the milk's microbiological safety and retains more of its biologically and nutritionally active compounds, but the cost of implementing this technology for a human milk bank is unknown.

METHODS

A cost-minimization study was carried out on the facilities of a regional human milk bank in a public hospital. Total production costs (fixed plus variables) were quantified using HTST pasteurization and HoP in three hypothetical scenarios: (1) costs of the first 10 L of pasteurized milk in a newly opened milk bank; (2) costs of the first 10 L of pasteurized milk in an active milk bank; and (3) costs using the maximum production capacity of both technologies in the first two years of operation. The following costs were analyzed: health care professionals, equipment and software, external services, and consumables.

RESULTS

In scenario 1, the total production costs were € 228,097.00 for the HTST method versus € 154,064.00 for the HoP method. In scenario 2, these costs were similar (€ 6,594.00 for HTST pasteurization versus € 5,912.00 for HoP). The cost of healthcare professionals was reduced by more than half when pasteurization was carried out by the HTST method versus the Holder method (€ 84.00 and € 191.00, respectively). In scenario 3, the unit cost of milk pasteurized by the HTST method decreased from the first to the second year by 43.5%, while for the HoP method, it decreased by 30%.

CONCLUSIONS

HTST pasteurization requires a high initial investment in equipment; however, it provides a significant minimization of production costs in the long term, pasteurizes large quantities of donor milk per working day and achieves a more efficient management of the time of the health care professionals in charge of the bank's operation compared to HoP.

[Variation in the level of the biocomponents immunoglobulin A and lactoferrin in human milk after Holder pasteurization]

BACKGROUND

breast milk is the ideal food for newborns and infants, but there are factors that can prevent the practice of breastfeeding. Human milk banks (BLH) are a strategy to increase breastfeeding coverage; the donated milk is subjected to Holder pasteurization to guarantee its innocuousness, undergoing large changes in temperature and a decrease in the concentrations of biocomponents such as Immunoglobulin A (IgA) and lactoferrin (LF). This article describes the results of recent studies on the impact of Holder pasteurization on IgA and LF in human milk.

MATERIAL AND METHODS

a search for research articles related to the topic of interest was carried out in various databases and in accordance with inclusion criteria that considered the type of study, date of publication and quality of the journal.

RESULTS

the impact of Holder pasteurization on IgA and LF concentrations is not clear, given that the literature reports a variety of protocols and different results; however, the percentage reductions of both biocomponents are significant and consistent in the studies reviewed, suggesting the importance of establishing a standard protocol for their quantification.

CONCLUSIONS

Holder pasteurization guarantees the microbiological quality of the milk distributed in HMB, but affects the amount of beneficial biocomponents for the final recipient. Government entities that regulate HMBs should evaluate the possibility of using other techniques that reduce the impact on biocomponents while preserving the microbiological quality of the product.

A novel heat treatment protocol for human milk

Human milk (HM) is the recommended nutrition for premature infants, but it may require processing to ensure microbial safety. The current standard is Holder pasteurisation (HoP), i.e. heating milk at 62.5 ± 0.5°C for 30 min, which eliminates bacteria but destroys heat labile bioactive HM components. We aimed to test an alternative thermal method, high-temperature short-time (HTST) pasteurisation using a modified Holder pasteurisation platform as this method has shown to preserve proteins in experimental HM flow pasteurisers. We analysed the ability of this batch process to eliminate bacterial species and to retain alkaline phosphatase, secretory immunoglobulin A and lactoferrin in HM. HTST at 81°C/5 s was as effective as HoP in bacterial count reduction while the retention of bioactive components was only improved at 62°C/5 s as compared to 72°C/5 s and HoP. HTST is a promising alternative to HoP but an optimal temperature-time combination needs to be determined for each technical platform separately.

Characteristics and qualities of edible bird's nest beverage as affected by thermal pasteurization and sterilization

Edible bird's nest beverage (B-nest-Bev) was produced from edible bird's nest (B-nest) flakes using different thermal processes. Pasteurization of B-nest-Bev at a low temperature for a longer time (LTLT) or at a high temperature for a shorter time (HTST) resulted in lower CIE L * , CIE a * , CIE b * -values, and drained weight (p < 0.05) than sterilization (118 or 121 °C). Sterilized and pasteurized B-nest-Bev had similar soluble solid contents and pH (p < 0.05). Nevertheless, acidified beverages pasteurized via either LTLT or HTST process had a marked decrease in sialic acid content. In addition, drastic protein degradation occurred in pasteurized acidified beverages, regardless of the conditions used, ascertained by the disappearance of major protein bands. However, polymerization of proteins took place in sterilized samples, irrespective of the temperature used. After digestion in a gastrointestinal tract model system (GIMs), all samples had increased (p < 0.05) antioxidant activities including DPPH and ABTS radical scavenging activities, ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC). B-nest-Bev subjected to HTST pasteurization or sterilization at 121 °C had the best appearance and acceptability among all the treatments used. Therefore, thermal processes directly affected the properties and acceptability of B-nest-Bev.

How to Provide Breast Milk for the Preterm Infant and Avoid Symptomatic Cytomegalovirus Infection with Possible Long-Term Sequelae

Cytomegalovirus (CMV) is able to replicate in the breast milk of lactating mothers and thus the offspring might be affected by mild to severe symptoms of postnatal CMV disease in case of prematurity; not in term infants. Sepsis-like syndrome affects only very low birth infants; and few cases have been reported. The neurodevelopmental long-term outcome of those preterm infants revealed possible subtle deficiencies, but no major neurodevelopmental impairment. Neurodevelopmental sequelae are still in discussion and seem somewhat overestimated after careful evaluation of the published evidence. The main focus of postnatal CMV disease lies upon the extremely low birth weight of infants. Elimination of CMV is provided by short-term heating methods like the most widely used Holder pasteurization. Freezing and thawing methods leave a risk for CMV acquisition. The benefits of untreated breast milk have to be considered to outweigh the possible sequelae of postnatal CMV infection in the most vulnerable preterm infants.

Effect of microwave and convection heating on selected nutrients of human milk

The aim of this study was to determine the influence of the microwave heating method (MWH) on selected determinants of the nutritional value of human milk (HM) and compare to the effect exerted by the standard convection heating (CH) method, including holder pasteurization (HoP). It was showed that using MWH under conditions assumed to ensure microbiological safety, changes in the level of the nutrients were not observed. In these conditions concentration of fatty acids (FAs), lipid peroxides (LP) and α-lactalbumin (α-La) were on a similar level as in raw milk, and furosine was not formed. MWH treatment of HM led to slight increase in the malonaldehyde (MDA) and protein carbonyls (PC) content. However, MDA content in HM as a result of MWH was lower than after application CH.

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.

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.

Holder Pasteurization: Comparison of Water-Bath and Dry-Tempering Devices

BACKGROUND

Human milk (HM) for premature infants is frequently Holder pasteurized (heated at 62.5 ± 0.5°C for 30 min) despite its detrimental effects on heat-sensitive milk components. This tolerated compromise ensures HM's microbial safety while less detrimental methods like short-time HM treatments (HTST) are still being evaluated. Dry-tempering devices (DT-HoP) were recently introduced in clinical practice due to hygienic concerns about water-based Holder pasteurizers (WB-HoP). Evidence on the impact of such dry-tempering devices on HM quality is lacking. The aim of this study was to compare protein retention rates after DT-HoP, WB-HoP and HTST.

METHODS

We colorimetrically determined alkaline phosphatase activity (ALP), concentrations of secretory immunoglobulin A (sIgA), and lactoferrin (LF) before and after DT-HoP, WB-HoP and HTST.

RESULTS

ALP was below the detection limit after HoP, but retained 52.8 ± 13% activity after HTST (p < 0.01). Secretory IgA (WB-HoP = 73.2 ± 13.5% vs. DT-HoP = 57 ± 14%, p = 0.0018) and LF retention (WB-HoP=47 ± 40% vs. DT-HoP=25 ± 8%, p = 0.07) differed between the two HoP modes. Again, retention was better maintained after HTST compared to HoP (80.4 ± 23% sIgA and 70 ± 42% LF concentration, all p < 0.01).

CONCLUSION

Dry-tempering milk lowers even further the quality of HM when performing HoP compared to water-bath pasteurization, while HTST warrants continued evaluation for clinical application.

A novel continuous hydrodynamic cavitation technology for the inactivation of pathogens in milk

Hydrodynamic cavitation is a powerful tool for the enhancement of various processing applications. This study utilizes continuous hydrodynamic cavitation (CHC) for the inactivation of pathogens in milk for the first time. The thermal characteristics, inactivation performance, damage on the nutritional composition, product safety, and cost of the advanced rotational hydrodynamic cavitation reactor at pilot scale were comprehensively investigated. The inactivation results demonstrated that 5.89, 5.53, and 2.99 ± 0.08 log reductions of Escherichia coli, Staphylococcus aureus, and Bacillus cereus were achieved, respectively, at a final treatment temperature of 70 °C for 1-2 s. Moreover, the detrimental effect of CHC on the nutritional composition of milk, including mineral, fat, protein, and vitamin contents, was similar to that of high-temperature short-time method. The change in the concentrations of general bacteria and E. coli, as well as the pH value and acidity of the CHC treated milk stored at 5 °C for 14 days was found to be close to that of low-temperature long-time pasteurized milk. The cost of the present CHC treatment was $0.00268/L with a production rate of 4.2 L/min. CHC appears to be a remarkable method for the continuous processing of milk, as well as other liquid foods with high nutrition and "fresh-picked" flavor, due to its high efficacy, good scalability, high production capacity, and low operating and equipment costs.

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.

The Revolution of Breast Milk: The Multiple Role of Human Milk Banking between Evidence and Experience-A Narrative Review

The review recalls the importance of breast milk and deepens the theme of human milk banking, a virtuous reality that is expanding all over the world but is still little known. In the last 15 years, modern biological technologies have crystallized the concept of uniqueness and irreproducibility of human milk, by establishing three new principles: first: human milk: a "life-saving" drug; second: human milk: the best food for preterm infants; and third: human milk: the main component of premature infant care. Our experience teaches us that human milk banking plays many roles that need to be known and shared.

Cloning, expression, and bioinformatics analysis and characterization of a β-galactosidase from Bacillus coagulans T242

The activities of β-galactosidases from bacteria and molds are affected by temperature, pH, and other factors in the processing of dairy products, limiting their application, so it is necessary to find alternative lactases. In this study, the β-galactosidase gene from Bacillus coagulans T242 was cloned, co-expressed with a molecular chaperone in Escherichia coli BL21, and subjected to bioinformatic and kinetic analyses and lactase characterization. The results show that the enzyme is a novel thermostable neutral lactase with optimum hydrolytic activity at pH 6.8 and 50°C. The thermal stability and increased lactose hydrolysis activity of β-galactosidase in the presence of Ca²⁺ indicated its potential application in the dairy industry.

Bioactive proteins in bovine colostrum and effects of heating, drying and irradiation

Bovine colostrum (BC) contains bioactive proteins, such as immunoglobulin G (IgG), lactoferrin (LF) and lactoperoxidase (LP). BC was subjected to low-temperature, long-time pasteurization (LTLT, 63 °C, 30 min) or high-temperature, short-time pasteurization (HTST, 72 °C, 15 s) and spray-drying (SD), with or without γ-irradiation (GI, ∼14 kGy) to remove microbial contamination. Relative to unpasteurized liquid BC, SD plus GI increased protein denaturation by 6 and 11%, respectively, increasing to 19 and 27% after LTLT and to 48% after HTST, with no further effects after GI (all P < 0.05). LTLT, without or with GI, resulted in 15 or 29% denaturation of IgG, compared with non-pasteurized BC, and 34 or 58% for HTST treatment (all P < 0.05, except LTLT without GI). For IgG, only GI, not SD or LTLT, increased denaturation (30-38%, P < 0.05) but HTST increased denaturation to 40%, with further increases after GI (60%, P < 0.05). LTLT and HTST reduced LP levels (56 and 81% respectively) and LTLT reduced LF levels (21%), especially together with GI (47%, P < 0.05). Denaturation of BSA, β-LgA, β-LgB and α-La were similar to IgG. Methionine, a protective amino acid against free oxygen radicals, was oxidised by LTLT + GI (P < 0.05) while LTLT and HTST had no effect. Many anti-inflammatory proteins, including serpin anti-proteinases were highly sensitive to HTST and GI but preserved after LTLT pasteurization. LTLT, followed by SD is an optimal processing technique preserving bioactive proteins when powdered BC is used as a diet supplement for sensitive patients.

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.

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.

Impact of Holder pasteurization on immunological properties of human breast milk over the first year of lactation

BACKGROUND

The timing of milk donations to human milk banks ranges from a few days to more than 1 year after delivery, and the Holder method is used for pasteurization. We evaluated the effect of temporal variation and thermal treatment on the immunological properties of milk.

METHODS

We analyzed 73 milk samples, raw and after pasteurization, donated at different lactation stages. We studied antibodies, lysozyme, cytokines, soluble receptors, and factors with impact on barrier function. We also evaluated in vitro the capacity of milk to modulate nuclear factor-κB (NF-κB) signaling in an HT-29 epithelial cell line stimulated with tumor necrosis factor-α (TNF-α).

RESULTS

With few exceptions, immune components exhibited their highest levels in colostrum, and were stable in the various stages of mature milk. Pasteurization altered the immunological composition of milk, and very drastically for some components. Raw milk of the first year reduced NF-κB activation in HT-29 cells treated with TNF-α to approximately the same extent, and Holder pasteurization significantly affected this capacity.

CONCLUSIONS

Overall, the present work reports that mature donated milk is equally valuable over the first year of lactation, but warns about drastic losses of anti-inflammatory properties during Holder pasteurization that could be critical for the health of preterm infants.

Evaluation of Human Milk Microbiota by 16S rRNA Gene Next-Generation Sequencing (NGS) and Cultivation/MALDI-TOF Mass Spectrometry Identification

The aim of the present study was to characterize human milk microbiota (HMM) with 16S rRNA gene amplicon next-generation sequencing and cultivation/matrix-assisted laser desorption/ionization (MALDI)-time of flight (TOF) mass spectrometry (MS) identification approaches. We analyzed 31 human milk samples from healthy Slovenian mothers. To check the accuracy of MALDI-TOF MS identification, several colonies representing most abundant genera and those, which could not be reliably identified by MALDI-TOF, were subjected to Sanger sequencing of their 16S rRNA gene. We showed that cultivation/MALDI-TOF MS was a suitable tool for culture-dependent determination of HMM. With both approaches, Staphylococcus and Streptococcus were found as predominant genera in HMM and the abundance of Staphylococcus was associated with decreased microbial diversity. In addition, we characterized factors that might influence HMM. The use of a breast pump was significantly associated with composition of HMM, lower microbial load, and higher abundance of cultivable staphylococci. Moreover, our study suggests that administration of probiotics to the suckling infant might influence HMM by increased abundance of lactobacilli and the presence of viable probiotic bacteria in human milk. However, since our study was observational with relatively small sample size, more targeted studies are needed to study possible transfer of probiotics to the mammary gland via an external route and the physiological relevance of these events.

Innovative Techniques of Processing Human Milk to Preserve Key Components

Human milk not only contains all nutritional elements that an infant requires, but is also the source of components whose regulatory role was confirmed by demonstrating health-related deficiencies in formula-fed children. A human milk diet is especially important for premature babies in the neonatal intensive care unit (NICU). In cases where breastfeeding is not possible and the mother's own milk is insufficient in volume, the most preferred food is pasteurized donor milk. The number of human milk banks has increased recently but their technical infrastructure is continuously developing. Heat treatment at a low temperature and long time, also known as holder pasteurization (62.5 °C, 30 min), is the most widespread method of human milk processing, whose effects on the quality of donor milk is well documented. Holder pasteurization destroys vegetative forms of bacteria and most viruses including human immunodeficiency virus (HIV) herpes and cytomegalovirus (CMV). The macronutrients remain relatively intact but various beneficial components are destroyed completely or compromised. Enzymes and immune cells are the most heat sensitive elements. The bactericidal capacity of heat-pasteurized milk is lower than that of untreated milk. The aim of the study was for a comprehensive comparison of currently tested methods of improving the preservation stage. Innovative techniques of milk processing should minimize the risk of milk-borne infections and preserve the bioactivity of this complex biological fluid better than the holder method. In the present paper, the most promising thermal pasteurization condition (72 °C-75 °C,) and a few non-thermal processes were discussed (high pressure processing, microwave irradiation). This narrative review presents an overview of methods of human milk preservation that have been explored to improve the safety and quality of donor milk.

High Hydrostatic Pressure Processing Better Preserves the Nutrient and Bioactive Compound Composition of Human Donor Milk

BACKGROUND

When mother's milk is insufficient, pasteurized human donor milk (DM) is the recommended supplement for hospitalized very-low-birth-weight infants. The current method of pasteurization (Holder, 62.5°C, 30 min) negatively affects heat-sensitive nutrients and bioactive proteins.

OBJECTIVES

Objectives of this study were to compare changes in DM composition after thermal pasteurization (Holder and flash-heating) and nonthermal methods [UV-C irradiation and high hydrostatic pressure (HHP)]. We hypothesized that nonthermal techniques would result in fewer changes to composition.

METHODS

Holder, flash-heating (brought to boil), UV-C irradiation (250 nm, 25 min), and HHP (500 MPa, 8 min) were studied. Pools of milk from 17 women known to contain bacteria at >5 × 107 colony forming units (CFU)/L were collected from the Rogers Hixon Ontario Human Milk Bank and underwent each pasteurization technique. Macronutrients, heat-sensitive micronutrients (vitamin C, folate), and bioactive components [bile-salt-stimulated lipase (BSSL), lysozyme, lactoferrin] were measured in raw and pools of pasteurized milk. Milk was cultured to determine how well each technique produced a culture negative result (detection limit <1 × 103 CFU/L).

RESULTS

Folate was reduced by 24-27% after Holder, flash-heating, and UV-C (P < 0.05); no reduction was observed after HHP. All pasteurization methods reduced vitamin C (60-75%, P < 0.001). BSSL was abolished after Holder and flash-heating (P < 0.001), reduced after UV-C (48%, P < 0.001), but unaffected by HHP. Lysozyme activity was reduced after flash-heating (44%) and UV-C (74%, P < 0.004) but unaffected by Holder or HHP. Lactoferrin was reduced by all methods (P < 0.02) but most severely by flash-heating (74%) and least severely by HHP (25%). Holder and UV-C reduced lactoferrin by ∼48%. All pasteurization methods reduced the number of culture positive DM samples (P < 0.001).

CONCLUSIONS

HHP better preserves human milk composition than Holder pasteurization. Future research on the feasibility of HHP for pasteurizing human milk is warranted because its implementation may improve the nutritional status and health of DM-fed infants.

Processing of Donor Human Milk: Update and Recommendations From the European Milk Bank Association (EMBA)

Background: A mother's own milk (MOM) is the gold standard for the feeding and nutrition of preterm and full term infants. When MOM is not available or there is not enough, donor human milk (DHM) should be used. Milk delivered to Human Milk Banks (HMBs) should be pasteurized to inactivate viral and bacterial agents. Currently, a pasteurization process at 62.5°C for 30 min (Holder pasteurization, HoP) is recommended in all international HMBs guidelines. State of the art: It is known that HoP affects some of the nutritional and biological components of human milk. Studies have demonstrated that temperature cycle in HoP is not always controlled or calibrated. A better check of these parameters in the pasteurizers on the market today may contribute to an improvement of the quality of HM, still maintaining some of the negative effects of the heat treatment of human milk. So, food industry, and dairy industry in particular, are evaluating innovative methodologies alternative to HoP to better preserve the nutritional and biological properties of fresh human milk, while assuring at least the same microbiological safety of HoP. The most studied processing techniques include High-Temperature-Short-Time (HTST) pasteurization, High Pressure Processing (HPP), and Ultraviolet-C (UV-C) irradiation. HTST is a thermal process in which milk is forced between plates or pipes that are heated on the outside by hot water at a temperature of 72°C for 5-15 s. HPP is a non-thermal processing method that can be applied to solid and liquid foods. This technology inactivates pathogenic microorganisms by applying a high hydrostatic pressure (usually 300-800 MPa) during short-term treatments (<5-10 min). UV irradiation utilizes short-wavelength ultraviolet radiation in the UV-C region (200-280 nm), which is harmful to microorganisms. It is effective in destroying the nucleic acids in these organisms, so that their DNA is disrupted by UV radiation. Aim: The aim of this paper is to present the EMBA recommendations on processing of HM, based on the most recent results obtained with these new technologies. Conclusions: Although research on the most promising technologies that will represent an alternative to HoP (HTST, HPP, UV-C) in the future is progressing, it is now important to recognize that the consistency and quality assurance of the pasteurizers on the market today represent a fundamental component that was previously lacking in the Holder approach.

Improving Pasteurization to Preserve the Biological Components of Donated Human Milk

Donor human milk (DHM) in human milk banks (HMB) is routinely subjected to heat treatment to ensure microbiological security, most guidelines recommending a temperature of 62. 5°C for 30 min. However, this procedure negatively impacts on milk quality, due to the destruction of biological components. Different studies have called for a more respectful treatment of DHM to preserve its properties, and have explored the use of alternative technologies. There is also clear evidence that bacterial and viral contamination in human milk can be effectively destroyed by temperatures lower than that currently recommended (62.5°C). Thus, a simple option would be to optimize the conventional pasteurization technique so the treated milk is free of infectious elements yet retains a maximum amount of biological components. An advantage of this approach is that it would be unnecessary to replace the pasteurization equipment currently available in most HMB. On the basis of a literature review, we here analyze and discuss evidence that pasteurization of human milk at a temperature below 62.5°C results in an improved preservation of its properties without compromising safety regarding the transmission of infectious agents.

Controversies in Breastfeeding

When addressing the compatibility of breastfeeding with certain maternal conditions, we need to differentiate between "contraindication" and "obstacle." Failure to distinguish between the two confuses new mothers and their families, and engenders misconceptions about breastfeeding advice by health professionals. Health conditions that may simply impede the initiation and duration of breastfeeding are often wrongly referred to as true contraindications to breastfeed, under the assumption that they might harm the health of the mother and/or that of the nursing infant. Here, we discuss several topics, including breast surgery, prolactinoma, concurrent new pregnancy, hormonal contraception, and use of medications and contrast agents, that continue to raise controversy. While most conditions appear to be compatible with breastfeeding, the major determinants of a woman's final choice of whether to nurse her infant or not are the attitude of health professionals and the state of mind of being an informed mother.

Better Control of Holder Pasteurization Results in Higher Retention of Human Milk Lactoferrin, IgA, and Lysozyme

Background: Holder pasteurization is commonly used in milk banks. We previously reported that the pattern of temperature and time may be different according to the pasteurizer used. Aim: The aim of our study was to assess the variances in pasteurization using two different devices: a standard pasteurizer (Past STD) and an optimized pasteurizer (Past OPTI). Methods: Immunoglobulin A (IgA), lactoferrin (LF), and lysozyme (LZ) content were assessed before and after pasteurization of 24 donor human milk samples. The impact of the pasteurization device was evaluated by testing 50- to 200-mL samples. Results: Mean temperature and duration of the plateau were 1.5°C lower and 11 min shorter, respectively, with Past OPTI vs. Past STD. The loss of IgA, LF, and LZ was 17.6, 5.6, and 9.8% lower, respectively, with Past OPTI than with Past STD. Conclusions: Accurate control of temperature enabled better preservation of IgA, LF, and LZ in donor milk. Holder pasteurization should be optimized, and new techniques proposed to treat donor milk should be compared with Holder pasteurization performed with a well-controlled device under realistic conditions.

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.