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.
Global outlook according to breastfeeding challenges
While Human Breast Milk (HBM) is often endorsed as the gold standard for neonatal nutrition (1–4), the 2022 Breastfeeding Report Card from the Centers for Disease Control and Prevention (5) reported that the majority (83.2%) of infants born during 2019 in the US began receiving breast milk, and 78.6% were still receiving breast milk at 1 month; however, at 6 months, only 24.9% of infants were exclusively breastfed, while 55.8% occasionally drank breast milk (Figure 1). Also, data reported by UNICEF points out that, according to 2017 data, only 41%–64% of babies were still breastfed at 2 years old (6). These trends have diverse implications, ranging from an increased risk of obesity in the child to various physical and emotional challenges for the mother (7–9).
To address the decline in breastfeeding, it is crucial to comprehend the underlying reasons. While there are numerous factors at play, two prevalent situations arise where direct breastfeeding becomes challenging: (1) When a neonate born preterm requires being introduced to a Neonatal Intensive Care Unit (NICU) (10), (2) Working mothers (representing more than half of mothers, in the US), must go outside the home without their babies, to continue with their professional life (9).
Preservation Methods for Human Breast Milk: Ensuring Optimal Nutrition in the Absence of Direct Breastfeeding
In both scenarios, the core requirement remains consistent: since these babies cannot be breastfed, alternatives must be sought to provide them with HBM when their mothers are not present. Technologies like Holder Pasteurization (HoP), High-Temperature Short-Time (HTST) Pasteurization, High-Pressure Processing (HPP), Ultraviolet (UV) radiation, and Pulsed Electric Fields (PEF) emerge as viable milk preservation methods, each presenting its own set of benefits and limitations.
Considering these factors, this review delves into characterizing HBM as a living fluid, emphasizing its relevance for individual children and society at large. From this perspective, we review the effects of the preservation treatments on the milk’s microbiological, bioactive, and nutritional profiles. The aim is to identify viable alternatives that facilitate prolonged lactation, enabling newborns to be fed exclusively on high-quality HBM for the first 6 months and continue for 12 months, as recommended by major US medical organizations (11), ensuring that infants receive optimal nutrition even when not in immediate proximity to their mothers.
