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

Abstract

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.

Changes in the Bacterial Diversity of Human Milk during Late Lactation Period (Weeks 21 to 48)

“…Members of genus Bacillus are ubiquitous, sporulating, saprophytic microorganisms that can readily contaminate human milk during its collection or storage [29]. Among them, B. cereus is a matter of concern in stored breast milk (specially in breast milk banks) since it can produce food poisoning toxins and may also cause severe illness in neonates [29][30][31]. On the other hand, selected strains of Bacillus species are commercialized as human probiotics [32] and strains of Bacillus coaulans and Bacillus clausii are being investigated for pediatric and infant formula applications [33][34][35].…”

Donor human milk programs in German, Austrian and Swiss neonatal units - findings from an international survey

“…Pasteurization of DHM is recommended to prevent the transmission of potentially harmful microbiota to the premature recipients [12,16,17]. The adverse impact of Holder-pasteurization on the quality of banked DHM is well known but alternatives to Holder pasteurization are limited [18,19]. Freeze-thawing and short time pasteurization as performed in some units may not effectively inactivate cytomegalovirus or sufficiently reduce bacterial counts [20,21].…”

Human milk pasteurisation reduces pre-lipolysis but not digestive lipolysis and moderately decreases intestinal lipid uptake in a combination of preterm infant in vitro models

“…However, the use of DHM presents significant challenges including the need for pasteurisation. Holder pasteurisation (62.5°C for 30 min) is recommended by all international human milk bank guidelines to prevent infections potentially transmitted by DHM (AAP Committee on Nutrition et al, 2017;Moro et al, 2019). Nevertheless, pasteurisation modifies some of milk properties, as protein denaturation and aggregation on the milk fat globule.…”