Macronutrients, total aerobic bacteria counts and serum proteome of human milk during refrigerated storage

Food-Derived Compounds Extend the Shelf-Life of Frozen Human Milk

Breastmilk is known to provide optimal nutrition for infant growth and development. A cross-sectional analysis of nationally representative US data from 2016 to 2021 revealed that >90% of lactating mothers reported using breast pumps to express milk.1 We conducted a survey of n = 1,049 lactating or recently lactating individuals from a US nationally representative population to explore breastmilk storage practices among this group. The data revealed that 83% of respondents store breastmilk in their homes, with 68% using freezers to do so for >1 month. The lowest available temperature in most household freezers is -20 °C, a temperature that is inadequate to maintain human milk's emulsified structure, leading to separation, degradation of fats, loss of key vitamins, and changes in palatability. We developed a first-of-its-kind high-throughput screening platform to identify food-derived compounds and combinations of compounds that, when added to human breastmilk, preserve fat content, retain antioxidant capacity, and reduce production of rancid-associated free fatty acids during extended freezer storage. These formulations represent leads for the development of safe and affordable frozen breastmilk shelf-life extenders for easy at-home use to increase the longevity of stored breastmilk.

Which is the optimal choice for neonates' formula or breast milk?

The incidence of prematurity has been increasing since the twenty-first century. Premature neonates are extremely vulnerable and require a rich supply of nutrients, including carbohydrates, proteins, docosahexaenoic acid (DHA), arachidonic acid (ARA) and others. Typical breast milk serves as the primary source for infants under six months old to provide these nutrients. However, depending on the individual needs of preterm infants, a more diverse and intricate range of nutrients may be necessary. This paper provides a comprehensive review of the current research progress on the physical and chemical properties, biological activity, function, and structure of breast milk, as well as explores the relationship between the main components of milk globular membrane and infant growth. Additionally, compare the nutritional composition of milk from different mammals and newborn milk powder, providing a comprehensive understanding of the differences in milk composition and detailed reference for meeting daily nutritional needs during lactation.

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.

Influence of Homogenization in the Physicochemical Quality of Human Milk and Fat Retention in Gastric Tubes

BACKGROUND

The retention of human milk nutrients in gastric tubes used to feed premature infants is a challenge to be overcome.

RESEARCH AIMS

To evaluate (1) the performance of six homogenizers (mixing processor, piston valve, ultrasonic bath, ultraturrax, stirring mixer, and ultrasound probe) for the fat retention reduction in gastric tubes; (2) the influence of the best homogenization conditions on the fatty acid and protein profiles of human milk; and (3) the cost/benefit ratio for the inclusion of homogenization as a new step in human milk processing.

METHODS

The influence of different levels and times of homogenization on reducing fat retention of human milk in probes was evaluated in this comparative prospective cross-sectional study. After homogenization, human milk flowed through a gavage and infusion pump apparatus used for feeding. Fat content was quantified before and after feeding. The techniques that reduced fat globule sizes and/or promoted a lower percentage of fat holding were evaluated for efficiency, variations in the fatty acid and protein profiles, and energy density and operating costs.

RESULTS

Homogenization led to a reduction in fat retention in feeding probes. The mixer processor and the ultrasound probe reduced fat retention by 99.23% (SD = 0.07) and 99.95% (SD = 0.02), respectively, and did not negatively influence fatty acid and protein profiles. The mixer processor demonstrated low energy density and low cost for human milk processing.

CONCLUSION

Homogenization promoted reduced fat retention in the feed probe and could help maintain fat nutrients of human milk during enteral feeding.

Proof-of-concept on the effect of human milk storage time: Lipid degradation and spectroscopic characterization using portable near-infrared spectrometer and chemometrics

Human milk (HM) modifications over time represent an important issue. This work proposed to evaluate the changes in HM during one-year storage through total lipids (TL) degradation and portable near-infrared (NIR) spectrometer combined with chemometrics. Colostrum, transition, and mature stages were obtained from donors and considered in the raw and pasteurized forms. Principal component analysis in TL content showed changes in the mature stages for both forms after 75 days. Multivariate curve resolution with alternating least squares in NIR spectral data reveals a decrease in protein and triacylglycerol contents while an increase in free fatty acids (palmitic acid) contents were observed through the storage after around 5-6 months. Therefore, more than 5-6 months of storage suggest possible biochemical changes in the HM nutritional composition. Moreover, the chemometrics investigation was crucial in extracting information, bringing coherent results, and helping to understand the chemical changes in human milk during storage.

Human milk proteome: what's new?

PURPOSE OF REVIEW

The proteome is one of the most complicated and multifunctional components in human milk. Recently, numerous novel characteristics of the human milk proteome have been discovered, which are described and critically examined in this review.

RECENT FINDINGS

Recent human milk proteomics studies have focused on how external factors like geography and environment, or maternal and infant's factors affect the milk proteins, endogenous peptides, their posttransitional modifications (PTMs) and infant utilization. Most of these studies have shown that major protein and endogenous peptide profiles are similar for healthy women and infants. The human milk proteome has been expanded by providing novel insights into PTMs like glycosylation and phosphorylation, and how the proteins and peptides are digested and utilized by the infant. All human milk proteomics studies are subject to conditions in which the samples were collected, handled and stored.

SUMMARY

Significant technological advancements in mass spectrometry have considerably enabled a deeper and more comprehensive identification and characterization of the expanded human milk proteome. However, data concerning human milk from mothers with infections or illnesses and mothers nursing more vulnerable infants are still limited and the roles of the components of the human milk proteome have not yet been sufficiently elucidated.

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

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