Donor Human Milk: Effects of Storage and Heat Treatment on Oxidative Stress Markers

Mother's own milk is the first choice for the feeding and nutrition of preterm and term newborns. When mother's own milk is unavailable or in short supply donor human milk (DM) could represent a solution. Heat treatment and cold storage are common practices in Human Milk Banks (HMBs). Currently, Holder pasteurization process is the recommended heat treatment in all international guidelines. This method is thought to lead to a good compromise between the microbiological safety and nutritional/biological quality of DM. Moreover, storage of refrigerated milk is a common practice in HMBs and in NICUs. Depending on the length and on the type of storage, human milk may lose some important nutritional and functional properties. The available data on oxidative stress markers confirm that pasteurization and refrigeration affected this important elements to variable degrees, even though it is rather difficult to quantify the level of deterioration. Nonetheless, clinical practice demonstrates that many beneficial properties of human milk are preserved, even after cold storage and heat treatment. Future studies should be focused on the evaluation of new pasteurization techniques, in order to achieve a better compromise between biological quality and safety of DM

New perspectives in human milk banks

Mother’s own milk (MOM) is the first choice in preterm infant feeding, and when it is not available or is insufficient, donor human milk (DHM) is recommended. It has been shown that feeding preterm infants with human milk is less related to major morbidities, enhances feeding tolerance and prevents metabolic syndrome in childhood. As The Committee on Nutrition of the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) states, specific guidelines for Human Milk Banks (HMB) are needed to guarantee the best possible compromise between microbiological safety and nutritional/biological quality of human milk (HM). Currently, Holder pasteurization (HoP: pasteurization process at 62.5-63°C for 30 minutes) is recommended by all international guidelines: this method inactivates bacterial and viral pathogens but it also affects some nutritional and biological properties of human milk. New methods to ameliorate the biological quality and safety of DHM are under investigation in the last years. High Pressure Processing (HPP) is a non- thermal process used in food industries: this technology inactivates pathogenic microorganisms by applying hydrostatic high pressure, however further researches are required before applying this technology in milk banking. Ultraviolet-C irradiation (UV-C) is another non-thermal method capable of reducing vegetative bacteria in human milk and it also seems to preserve higher levels of immunological proteins than HoP. High-temperature short-time pasteurization (HTST: flash pasteurization, 72°C for 5-15 seconds) currently is available only at industrial level, but it could represent an alternative to HoP seeming to maintain the protein profile and some of the key active components of DHM. Further researches are needed to define the optimal treatment of DHM.   Proceedings of the 11th International Workshop on Neonatology and Satellite Meetings · Cagliari (Italy) · October 26th-31st, 2015 · From the womb to the adult Guest Editors: Vassilios Fanos (Cagliari, Italy), Michele Mussap (Genoa, Italy), Antonio Del Vecchio (Bari, Italy), Bo Sun (Shanghai, China), Dorret I. Boomsma (Amsterdam, the Netherlands), Gavino Faa (Cagliari, Italy), Antonio Giordano (Philadelphia, USA

The effect of holder pasteurization on nutrients and biologically-active components in donor human milk: A review

When a mother’s milk is unavailable, the best alternative is donor milk (DM). Milk delivered to Human Milk Banks should be pasteurized in order to inactivate the microbial agents that may be present. Currently, pasteurization, performed at 62.5 °C for 30 min (Holder Pasteurization, HoP), is recommended for this purpose in international guidelines. Several studies have been performed to investigate the effects of HoP on the properties of DM. The present paper has the aim of reviewing the published papers on this topic, and to provide a comparison of the reported variations of biologically-active DM components before and after HoP. This review was performed by searching the MEDLINE, EMBASE, CINHAL and Cochrane Library databases. Studies that clearly identified the HoP parameters and compared the same DM samples, before and after pasteurization, were focused on. A total of 44 articles satisfied the above criteria, and were therefore selected. The findings from the literature report variable results. A possible explanation for this may be the heterogeneity of the test protocols that were applied. Moreover, the present review spans more than five decades, and modern pasteurizers may be able to modify the degradation kinetics for heat-sensitive substances, compared to older ones. Overall, the data indicate that HoP affects several milk components, although it is difficult to quantify the degradation degree. However, clinical practices demonstrate that many beneficial properties of DM still persist after HoP

Effects of Holder pasteurization on the protein profile of human milk

BACKGROUND: The most widespread method for the treatment of donor milk is the Holder pasteurization (HoP). The available literature data show that HoP may cause degradation of some bioactive components. The aim of this study was to determine the effect of HoP on the protein profile of human milk (HM) using a GeLC-MS method, a proteomic approach and a promising technique able to offer a qualitative HM protein profile. METHODS: HM samples were collected by standardized methods from 20 mothers carrying both preterm and term newborns. A aliquot of each sample was immediately frozen at -80 °C, whilst another one was Holder pasteurized and then frozen. All samples were then analyzed by GeLC-MS. The protein bands of interest were excised from the gel, digested with trypsin and identified by nano-HPLC-MS/MS analysis. RESULTS: The protein profile before and after HoP showed qualitative differences only in 6 samples out of 20, while in the remaining 14 no detectable differences were found. The differences interested only colostrums and transitional milk samples and regarded the decrease of the electrophoretic bands corresponding to alpha and beta-casein, tenascin, lactoferrin and immunoglobulin. CONCLUSIONS: In the majority of samples, HoP did not cause any modification, thereby preserving the biological activity of HM proteins

New human milk fortifiers for the preterm infant

Given its unique nutritional and functional advantages, human milk (HM) should be considered as the first choice for the nutrition of all infants, including preterm newborns. Since its protein, mineral and energy contents are not suitable to meet the high needs of very-low-birth-weight (VLBW) infants, HM should be fortified for these components. Fortification of HM is an important nutritional intervention in order to provide appropriate nutritional intake and appropriate growth. The standard fortification strategy has yielded inadequate protein intakes, resulting in slower growth as compared to preterm formulas. Improvement of outcomes depends on new fortification strategies, considering the large variability of HM composition. Individualized fortification, either targeted or adjustable, has been shown to be effective and practical in attaining adequate protein intakes and growth.<br />Most commercially available multi-nutrient fortifiers and protein concentrates are derived from bovine milk (BM), which has a protein composition very different from that of HM. The use of BM proteins has been recently questioned for possible association with intestinal inflammation in VLBW infants. Recently, one HM-based fortifier was shown to be associated with lower necrotizing enterocolitis rates and lower mortality in extremely premature infants, compared to BM-based products. Other milk sources are currently under evaluation: a randomized, controlled, single-blind clinical trial, coordinated by the Neonatal Unit of the University of Turin in collaboration with the Italian National Research Council of Turin and the University of Cagliari, is being carried out to evaluate the adequacy of fortifiers derived from donkey milk for the nutrition of preterm infants