Application of pressure homogenization on whole human milk pasteurized by high hydrostatic pressure: Effect on protein aggregates in milk fat globule membrane and skim milk phases.

This study explored the impact of homogenization (at pressures of 16, 30, and 45 MPa) on both raw and high hydrostatic pressure (HHP)-treated human milk (HM). It focused on protein compositions and binding forces of soluble and insoluble fractions for both milk fat globule membrane (MFGM) and skim milk. Mild homogenization of HHP-treated milk increased lactoferrin (LF) levels in the insoluble fractions of both MFGM and skim milk, due to insoluble aggregation through hydrophobic interactions. Intense homogenization of HHP-treated milk decreased the LF level in the MFGM fractions due to the LF desorption from the MFGM, which increased LF level in the insoluble skim milk fraction. Homogenized-HHP treated milk showed noticeably higher casein (CN) level at the MFGM compared to homogenized-raw milk, attributed to HHP effect on CN micelles. Overall, the combined use of HHP and shear-homogenization should be avoided as it increased the biological proteins in insoluble fractions.

SARS-CoV-2 antibodies and their neutralizing capacity against live virus in human milk after COVID-19 infection and vaccination: prospective cohort studies.

BACKGROUND: There is limited understanding of the impact of coronavirus disease 2019 (COVID-19) infection and vaccination type and interval on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) human milk antibodies and their neutralizing capacity. OBJECTIVES: These cohort studies aimed to determine the presence of antibodies and live virus neutralizing capacity in milk from females infected with COVID-19, unexposed milk bank donors, and vaccinated females and examine impacts of vaccine interval and type. METHODS: Milk was collected from participants infected with COVID-19 during pregnancy or lactation (Cohort-1) and milk bank donors (Cohort-2) from March 2020-July 2021 at 3 sequential 4-wk intervals and COVID-19 vaccinated participants with varying dose intervals (Cohort-3) (January-October 2021). Cohort-1 and Cohort-3 were recruited from Sinai Health (patients) and through social media. Cohort-2 included Ontario Milk Bank donors. Milk was examined for SARS-CoV-2 antibodies and live virus neutralization. RESULTS: Of females with COVID-19, 53% (Cohort-1, n = 55) had anti-SARS-CoV-2 IgA antibodies in ≥1 milk sample. IgA+ samples (40%) were more likely neutralizing than IgA- samples (odds ratio [OR]: 2.18; 95% confidence interval [CI]: 1.03, 4.60; P = 0.04); however, 25% of IgA- samples were neutralizing. Both IgA positivity and neutralization decreased ∼6 mo after symptom onset (0-100 compared with 201+ d: IgA OR: 14.30; 95% CI: 1.08, 189.89; P = 0.04; neutralizing OR: 4.30; 95% CI: 1.55, 11.89; P = 0.005). Among milk bank donors (Cohort-2, n = 373), 4.3% had IgA antibodies; 23% of IgA+ samples were neutralizing. Vaccination (Cohort-3, n = 60) with mRNA-1273 and shorter vaccine intervals (3 to <6 wk) resulted in higher IgA and IgG than BNT162b2 (P < 0.04) and longer intervals (6 to <16 wk) (P≤0.02), respectively. Neutralizing capacity increased postvaccination (P = 0.04) but was not associated with antibody positivity. CONCLUSIONS: SARS-CoV-2 infection and vaccination (type and interval) impacted milk antibodies; however, antibody presence did not consistently predict live virus neutralization. Although human milk is unequivocally the best way to nourish infants, guidance on protection to infants following maternal infection/vaccination may require more nuanced messaging. This study was registered at clinicaltrials.gov as NCT04453969 and NCT04453982.

Characterization of protein aggregates in cream and skimmed human milk after heat and high-pressure pasteurization treatments.

Preservation processes applied to ensure microbial safety of human milk (HM) can modify the native structure of proteins and their bioactivities. Consequently, this study evaluated the effect of pasteurization methods (Holder pasteurization, high-temperature short-time (HTST), and high hydrostatic pressure (HHP)) of whole human milk (HM) on protein aggregates in skim milk and cream fractions. For heat-treated whole milk, insoluble protein aggregates at milk fat globule membrane (MFGM) were formed by disulfide and non-covalent bonds, but insoluble skim milk protein aggregates were only stabilized by non-covalent interactions. Contrary to heat treatment, the insolubilization of main proteins at the MFGM of HHP-treated HM was only through non-covalent interactions rather than disulfide bonds. Moreover, only heat treatment induced the insoluble aggregation of ⍺-lactalbumin. Overall, compared to heat treatment, HHP produced a milder effect on protein aggregation, validating the use of this process to better preserve the native state of HM bioactive proteins.

Digestion of human milk processed by high pressure processing and Holder pasteurization using a dynamic in vitro model of the preterm infant.

Holder pasteurization (HoP) (62.5 °C, 30 min) of donor human milk is widely used to inactivate potential pathogens but may lead to denaturation and aggregation of bioactive proteins, reducing their functionality. In contrast, high pressure processing (HPP) is a non-thermal technique that minimally affects assessed bioactive components; however, it is unclear how HPP affects protein digestion, and retention of functional bioactive proteins. Raw or processed (HoP; HPP[500 MPa,10 min]) pools of milk (N = 3, from 9 donors) were subjected in triplicate to in vitro digestion simulating the preterm infant gastrointestinal tract. Compared to raw or HPP, HoP increased intestinal proteolysis of lactoferrin and bioactive milk fat globule membrane proteins. Lysozyme activity was impacted by digestion following HoP (72 % to 7 %)-significantly more than HPP (75 % to 34 %) or raw (100 % to 39 %), which did not differ. Proteins in HPP-treated donor milk are digested no different than raw milk, while preserved bioactivity remains functional upon digestion.

Preservation of Anti-cytomegalovirus Activity in Human Milk Following High-Pressure Processing Compared to Holder Pasteurization.

Pasteurized donor human milk is recommended for hospitalized preterm infants when mother's own milk is unavailable. Our aim was to compare the antiviral activity of human milk processed by Holder pasteurization (HoP) or high-pressure processing (HPP) against representative enveloped and non-enveloped viruses including cytomegalovirus and hepatitis A virus. Expressed milk from 20 donors collected from the Ontario Milk Bank was combined into 10 pools, each from two unique donors. Each pool was processed by HoP (62.5°C, 30 min) or HPP (500 MPa, 8 min, 4°C) and subsequently inoculated with cytomegalovirus or hepatitis A virus to achieve a final concentration of 5-log plaque-forming units/mL. Plaque reduction assays were used to quantify detectable virus after 30 min incubation (room temperature). Post hoc experiments using a 4 h incubation time were conducted if reductions were detected at 30 min. Irrespective of processing, cytomegalovirus concentrations declined in all pools after 30 min incubation (P < 0.0001). Milk processed by HoP exhibited significantly less reduction compared to raw milk (P = 0.0069). In post hoc experiments, anti-cytomegalovirus activity was maintained at 4 h, with high inter-pool variability. Hepatitis A virus concentration remained unchanged after 30 min incubation in raw and processed milk. Anti-cytomegalovirus activity in human milk is preserved following HoP and HPP, persisting up to 4 h post-inoculation; anti-hepatitis A virus activity was not observed in raw or processed milk. Further research is needed to understand how HoP or promising alternative processing methods affect the antiviral activity of donated milk, given its potential importance to recipient infants.

Predicting Protein and Fat Content in Human Donor Milk Using Machine Learning.

BACKGROUND: Donor milk is the standard of care for hospitalized very low birth weight (VLBW) infants when mother's milk is unavailable; however, growth of donor milk-fed infants is frequently suboptimal. Variability in nutrient composition of donated milk complicates the production of a uniform pooled product and, subsequently, the provision of adequate nutrition to promote optimal growth and development of VLBW infants. We reasoned a machine learning approach to construct batches using characteristics of the milk donation might be an effective strategy in reducing the variability in donor milk product composition. OBJECTIVE: The objective of this study was to identify whether machine learning models can accurately predict donor milk macronutrient content. We focused on predicting fat and protein, given their well-established importance in VLBW infant growth outcomes. METHODS: Samples of donor milk, consisting of 272 individual donations and 61 pool samples, were collected from the Rogers Hixon Ontario Human Milk Bank and analyzed for macronutrient content. Four different machine learning models were constructed using independent variable groups associated with donations, donors, and donor-pumping practices. A baseline model was established using lactation stage and infant gestational status. Predictions were made for individual donations and resultant pools. RESULTS: Machine learning models predicted protein of individual donations and pools with a mean absolute error (MAE) of 0.16 g/dL and 0.10 g/dL, respectively. Individual donation and pooled fat predictions had an MAE of 0.91 g/dL and 0.42 g/dL, respectively. At both the individual donation and pool levels, protein predictions were significantly more accurate than baseline, whereas fat predictions were competitive with baseline. CONCLUSIONS: Machine learning models can provide accurate predictions of macronutrient content in donor milk. The macronutrient content of pooled milk had a lower prediction error, reinforcing the value of pooling practices. Future research should examine how macronutrient content predictions can be used to facilitate milk bank pooling strategies.

A Human Milk-Based Protein Concentrate Developed for Preterm Infants Retains Bioactive Proteins and Supports Growth of Weanling Rats.

BACKGROUND: Bovine milk-based protein modulars are currently available to nutrient-enrich enteral feedings; however, they have limitations for use in very-low-birth-weight infants. OBJECTIVES: Our objectives were to develop a human milk-based protein (HMP) concentrate and to conduct a preclinical assessment of the HMP concentrate in weanling rats. METHODS: An HMP concentrate was produced from donor milk using pressure-driven membrane filtration processes and high hydrostatic pressure processing. Protein and lactoferrin concentrations and lysozyme activity were determined by Kjeldahl, HPLC, and turbidimetric assay, respectively. Male Sprague Dawley rats 24 d old (n = 30) were randomly assigned to 1 of 3 isocaloric AIN-93G diets for 4 wk containing 100% casein (control) or with 50% of the casein replaced with the HMP concentrate (treatment) or a bovine whey protein isolate (treatment). Body weight, food intake, fat mass, plasma amino acid profiles, and organ weights were measured. Data were analyzed using linear regression models. RESULTS: Raw donor milk contained (mean ± SD) 101 ± 6 g protein/kg and 5 ± 1 g lactoferrin/kg of milk solids. Postprocessing, protein and lactoferrin concentrations were 589 ± 3 g/kg and 29 ± 10 g/kg, respectively. Lysozyme activity was initially 209 ± 4 U/kg and increased to 959 ± 39 U/kg in the HMP concentrate. There were no statistically significant differences in body weight, food intake, fat mass, or plasma amino acid profiles between rats fed diets containing the HMP concentrate and the control diet. Full cecum weights were higher in rats fed the HMP concentrate than in those fed control diets (mean difference: 5.59 g; 95% CI: 4.50, 6.68 g; P < 0.0001), likely reflecting the concentration of human milk oligosaccharides. No differences were found for other organ weights. CONCLUSIONS: The HMP concentrate retained important bioactive proteins and supported normal rat growth in the preclinical assessment.

Term Infants Fed Exclusively With Donor Milk May Require Vitamin C Supplementation.

BACKGROUND: When there is insufficient mother's milk for preterm infants, fortified human donor milk (DM) is the preferred supplement. Recently, there is growing interest in providing DM to term infants. Aside from vitamin D, mother's milk is a complete source of nutrition for term infants. It is unknown whether supplementation of micronutrients is required for term infants exclusively fed DM, particularly for nutrients affected by heat processing, such as vitamin C. The objective of this study was to determine the total vitamin C content in DM and whether it would be adequate for an infant exclusively fed DM. METHODS: DM samples (n = 56) were collected at a Canadian milk bank from April to August 2018. Vitamin C concentration was determined by high-performance liquid chromatography. RESULTS: DM samples had a vitamin C concentration of 17.7 ± 9.8 mg/L (mean ± SD) and were variable, ranging from 1.9 to 43.2 mg/L. Using these values and assuming an exclusive DM consumption of 780 mL/day, the estimated vitamin C intake would be 13.8 ± 8.6 mg (mean ± SD), falling below the adequate intake of 40 mg/day for infants (0-6 months old). CONCLUSION: Vitamin C supplementation is required for all infants if DM is the sole source of nutrition. Future studies should investigate other heat- and light-sensitive nutrients.

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.

Is Frozen Human Milk That Is Refused by Mother's Own Infant Suitable for Human Milk Bank Donation?

Background: Infant refusal to feed previously frozen human milk is thought possibly attributable to lipase, an enzyme that cleaves fatty acids from milk triglycerides potentially changing the taste of the milk. Previous reports suggest that this milk is not harmful to infants; however, the lipase activity, macronutrient content, concentration of free fatty acids (FFAs), pH, and bacterial load of milk that meets this criterion are not fully understood. Objective: The objective was to determine whether refused frozen milk is different in composition from typical milk deposits received at a human milk bank. Methods: Frozen milk deposits previously refused by mother's own infant were collected from 16 mothers at five different time points when available (postpartum days 30, 60, 90, 120, and 150). Lipase activity, macronutrient composition, levels of FFA, pH, and bacteriology were determined. Analysis of mature donor milk and bacteriology data from the Ontario milk bank were used as controls. Results: The lipase activity for all samples was at or below literature values for mature human milk and lower compared with control milk (p < 0.001) for all time periods except at day 30. Macronutrient composition was not different from control values and did not change significantly over 150 days, with the exception of crude protein, which declined with milk maturity (p < 0.005). The pH for all postpartum time groups was lower (p < 0.02) in refused milk, and was inversely associated with lipase activity and FFA. FFA and bacterial counts were not different from control samples. Conclusions: Infant refusal of previously frozen milk may not be entirely due to endogenous lipase activity. This milk appears suitable for donation to human milk banks.

Energy and Fat Intake for Preterm Infants Fed Donor Milk Is Significantly Impacted by Enteral Feeding Method.

BACKGROUND: Pasteurized donor milk is the recommended supplement for preterm infants when mother's milk volumes are insufficient. Compared with mother's milk, the macronutrient content of donor milk is thought to be lower due to pasteurization and additional container changes during processing. Given that poor growth is concerning for preterm infants, it is important to understand how processing and feeding methods influence the nutrition composition of donor milk feeds. The research aim of this study was to determine the effects of pasteurization and feeding method on the macronutrient and energy composition of donor milk. Ten donor milk pools were pasteurized, prepared according to neonatal practices, and infused through nasogastric tubes to simulate 4 feeding methods: bolus, 30 minutes, 60 minutes, and continuous feeding over 4 hours. Macronutrient concentrations were assessed after pasteurization, preparation, and each feeding method using a mid-infrared human milk analyzer. RESULTS: There were no significant decreases in macronutrient content after pasteurization or bolus feeding. However, energy and fat losses increased with slower infusion rates. After continuous feeding for 4 hours, energy and fat concentrations decreased by a mean of 17.3 (15.8-18.8) kcal/dL and 2.08 (1.90-2.25) g/dL (P < .0001), respectively. CONCLUSIONS: Pasteurization did not significantly reduce donor milk macronutrient and energy content; however, feeding method significantly impacted the final delivery of energy and fat.

Impact of Neonatal Intensive Care Unit Admission on Bacterial Colonization of Donated Human Milk.

BACKGROUND: Unpasteurized human donor milk typically contains a variety of bacteria. The impact of neonatal intensive care unit (NICU) admission of the donor's infant and duration of lactation on bacterial contamination of human milk is unknown. Research aim: This study aimed (a) to describe the frequency/concentration of skin commensal bacteria and pathogens in unpasteurized human donor milk and (b) to assess the impact of NICU admission and (c) the duration of milk expression on bacterial colonization of donated milk. METHODS: The authors conducted a retrospective cohort study of human milk donated to the Rogers Hixon Ontario Human Milk Bank from January 2013 to June 2014. Milk samples from each donor were cultured every 2 weeks. RESULTS: The study included 198 donor mothers, of whom 63 had infants admitted to the NICU. Of 1,289 cultures obtained, 1,031 (80%) had detectable bacterial growth and 363 (28%) yielded bacterial growth in excess of 107 cfu/L, a local threshold for allowable bacteria prior to pasteurization. The mean (standard deviation) donation period per donor was 13.0 (7.5) weeks. Milk from mothers with NICU exposure had significantly higher concentrations of commensals, but not pathogens, at every time period compared with other mothers. For every 1-month increase in donation from all donors, the odds ratio of presence of any commensal in milk increased by 1.13 (95% confidence interval [1.03, 1.23]) and any pathogen by 1.31 (95% confidence interval [1.20, 1.43]). CONCLUSION: Commensal bacteria were more abundant in donor milk expressed from mothers exposed to neonatal intensive care. Bacterial contamination increased over the milk donation period.

Human Milk for Ill and Medically Compromised Infants: Strategies and Ongoing Innovation.

The use of human milk (mother's own milk and/or donor milk) in ill or medically compromised infants frequently requires some adaptation to address medical diagnoses and/or altered nutrition requirements. This tutorial describes the nutrition and immunological benefits of breast milk as well as provides evidence for the use of donor milk when mother's own milk is unavailable. Several strategies used to modify human milk to meet the medical and nutrition needs of an ill or medically compromised infant are reviewed. These strategies include (1) the standard fortification of human milk to support adequate growth, (2) the novel concept of target fortification in preterm infants, (3) instructions on how to alter maternal diet to address cow's milk protein intolerance and/or allergy in breast milk-fed infants, and (4) the removal and modification of the fat in breast milk used in infants diagnosed with chylothorax.

Managing osteoporosis in a rural community.

Managing long-term conditions, such as osteoporosis in a rural community, presents particular challenges. This article describes how a specialist service identified patients at high risk of fragility fracture and raised awareness of bone health.

Effects of pasteurization on adiponectin and insulin concentrations in donor human milk.

Although pasteurization is recommended before distributing donor human milk in North America, limited data are available on its impact on metabolic hormones in milk. We aimed to investigate the effects of pasteurization on adiponectin and insulin concentrations in donor human milk. The study investigates concentrations of components in donor human milk before and after Holder pasteurization. After the guidelines of the Human Milk Bank Association of North America, human milk samples were pooled to produce 17 distinct batches (4 individuals per batch) and pasteurized at 62.5°C for 30 min. Adiponectin, insulin, energy, fat, total protein, and glucose concentrations were measured pre- and postpasteurization. Pasteurization reduced milk adiponectin and insulin by 32.8 and 46.1%, respectively (both p < 0.0001). Adiponectin and insulin were significantly correlated with energy and fat milk composition (r = 0.36-0.47; all p < 0.05). Pasteurization effects on milk hormone concentrations remained significant after adjusting for fat and energy (beta ± SEE: -4.11 ± 1.27, p = 0.003 for adiponectin; -70.0 ± 15.0, p < 0.0001 for insulin). Holder pasteurization reduced adiponectin and insulin concentrations in donor human milk. In view of emerging knowledge on the importance of milk components, continued work to find the optimal pasteurization process that mitigates risks but promotes retention of bioactive components is needed.

Accuracy of comparing bone quality to chocolate bars for patient information purposes: observational study.

OBJECTIVE: To test whether standard information for patients using Crunchie and Aero chocolate bars to explain bone health and risk of fracture is robust. DESIGN: Observational study. SETTING: Domestic kitchen in rural west Wales. PARTICIPANTS: 10 Crunchie bars and 10 Aero bars. MAIN OUTCOME MEASURE: Fracture after falls from varying heights. RESULTS: Both Crunchie and Aero bars exhibited the same T and Z scores for bone density. Crunchie bars had a lower chocolate mass index than the Aero bars. Crunchie bars are more liable to fracture. CONCLUSIONS: Using Crunchie and Aero chocolate bars to explain bone structure to patients may be visually attractive but oversimplifies the situation.

Organizing palliative care for rural populations: a systematic review of the evidence.

BACKGROUND: Palliative care services have developed mostly in urban areas. Rural areas typically are characterized by the lack of well-organized services, with primary care professionals, specifically GPs and community nurses, having to undertake most of the palliative care. Little is known, however, either of their views or of how best to organize palliative care in rural areas. OBJECTIVE: The aim of this study was to conduct a systematic literature review of studies that have examined the organization of rural palliative care and the views of professionals in rural areas. METHOD: Six electronic databases were searched for published studies between 1991 and 2001. Articles had to match against (i). MeSH or keyword terms relating to palliative, terminal or end of life care; and (ii). MeSH or keyword terms relating to rural. A data extraction framework was designed and used systematically by two reviewers to consider research question and method, sample characteristics, selection and size, study quality, summary results and implications. RESULTS: Twenty-six studies were identified. These were mostly questionnaire surveys and reports, and three qualitative studies. No randomized controlled studies or cohort studies were identified. Education and strategic issues were dominant research questions. Both the sample numbers and response rates in the surveys were variable. The qualitative studies had methodological strengths and elicited important views from nurses, carers and families. GPs were, however, unrepresented. Whilst the role of primary care emerged as an important theme, primary care professionals reported difficulties in obtaining education and training. There were also reported problems in symptom control and in the management of emotional issues such as bereavement counselling. Difficulties were also described in accessing specialist services such as hospices, and families were reported as having problems in accessing information. Developments in information technology such as telemedicine were seen as possible solutions to some of the problems. CONCLUSIONS: There is little published work on this topic. Most of the work identifies problems in the delivery of palliative care in rural areas. Whilst primary care professionals are seen as having a key role, there is a need to discover both their views and their needs in this field.