VIII. Human Milk Banks

BACKGROUND Breast milk is essential to the development of the newborn's immature immune system and help to reduce child mortality. As preterm neonates are not able to Breast-feed early after birth these vulnerable infants are at greatest risk of not receiving breast milk. According to WHO, breast milk from their own mother is the first best option for preterm infants. When it is not possible, the next best option is DHM. WELL ESTABLISHED Human milk bank (HMB) is a facility established to recruit and screen breast milk donors, collect DHM, treat (bacteriological screening, pasteurization, storage), and distribute the HM. They also aim to promote/support breast-feeding, notably in mothers of hospitalized preterm infants. The presence of an HMB in a hospital improves breast-feeding rates at discharge from NICU (1). HMBs rely on a strong donor breast-feeding population to ensure adequate supply. Donors are mothers who have been carefully screened for health problems and give their extra-milk for vulnerable hospitalized babies, under medical prescription. Such an altruistic and generous act is based on the comprehension that, in preterm infants, the alternative to HM—preterm formula—increases the risks of complications such as NEC and deprives these infants of the benefits of breast milk on cognitive development (2). Mothers who give (or sell) their extra milk to another mother who delivered a well-being term baby who cannot get enough milk from his mother should not be spelled “donors” (3). To provide safe, high-quality DHM, HMBs with high-level quality assurance and tracking are required. As the number of HMBs increases, common core practices are required but there is not yet enough evidence, which leaves the field open to heterogeneity. In few countries, HMB associations elaborated consensus statements based on evidence, otherwise on experience (4–11). NOT YET ESTABLISHED Recruitment, Screening and Information of Potential Donors All donors should be screened through an oral interview or written questionnaire or a combination of the two. It screens for general health, alcohol consumption, medication and drug use and key infections (HIV type 1 or 2, hepatitis B, hepatitis C, syphilis, and HTLV type 1 or 2). Exclusion may be definitive (positive test for viruses, recreational drugs or tobacco products, excessive quantities of alcohol, medications contraindicated during breast-feeding) or temporary (health problems during the period of being a donor). There are significant differences depending on the country. For example, transfusion/blood products induce definitive exclusion in some countries, and only if transfusion/blood products occurred within the last 4 months in others countries. Then, donors must undergo serologic testing to screen for HIV, HTLV, hepatitis B and hepatitis C. In some countries, but not all, syphilis serology is required. The HMB should provide detailed information to donors, ensuring they fully understand their responsibility in maintaining the quality of the DHM. Finally, the HMB should obtain a written informed consent from each donor. Milk Expression, Storage and Transportation to HMB Donors should express, store, and transport their milk properly to avoid bacteriological contamination. As the mothers express their milk not only at hospital or HMB, but also at home, all these locations have to propose easy access to refrigerators and freezers, and transportation availability. All donors should receive instructions that emphasize the importance for proper milk expression (proper hygiene, hand washing), storage (suitable containers, labeling, how long milk can be stored in a refrigerator, whether multiple expressions should be allowed in the same container, and the length of time milk can be frozen at home before transportation to an HMB), and transportation (cold chain system). Milk that has been at room temperature for more than 6 hours should not be accepted for donation. Further follow-up of information and lactation support is needed. Education about the hand-expression of milk or the use of milk pump is requested, as there is significant risk of milk contamination from milk pump in the absence of clear cleaning instructions. When the HM is expressed at home, it should be stored in containers provided by the HMB, labeled (date of expression/freezing and donor's identification) and placed in a freezer immediately after expression. It should be transported to the HMB for processing within three weeks to one month of expression or when the expressed milk has reached the requested volume. When the HM is expressed in the hospital or HMB, where the procedures are well-established and health professionals are well-trained, HM must be immediately transferred to a refrigerator or freezer and frozen within 24 hours. Milk Handling and Processing in the HMB Donor milk containers must be labeled with a tracking identification number, along with the donor mother's information and date of collection/freezing. Some HMBs pool milk from multiple donors, which provides more consistent nutrient content, but it reinforces the need to trace the source of milk. Pre-Pasteurization Screening Some HMBs test for the presence of cow's milk protein, but there is a lack of simple, low-cost and efficient test. Furthermore it is particularly relevant only outside the setting of HMBs. It has been shown to be necessary when mothers get money by selling their milk, but the issue of milk purchased via internet is completely different from milk donation (12). In most countries donors are not paid or receive small financial compensation (10), so that there is no real temptation to add cow milk to their milk. In France, the test was used between 1999 and 2009. Using a questionnaire French HMBs association was able to estimate that about 99,500 tests were performed in 17 HMBs and less than 10 tests were positive (personal data). These cases were related to maternal psychiatric troubles and the amount of cow milk was so important that professionals working in the HMB easily detected the unusual white aspect of milk when compared to HM. Most HMBs test for total viable microbial content and other undesirable microbes. There is no consensus about the pre-pasteurization screening procedures. Some test all samples of pre-pasteurized milk, others test a single sample of milk for every batch of milk that is eventually pasteurized and the last ones test the first batch of milk from each donor at every donation, especially when there are changes in the mother's practices. Most HMBs test for total viable microorganisms, Staphylococcus aureus, and n some countries Enterobacteriaceae. Milk is discarded when total viable micro-organisms is >105 to 106 colony-forming units (CFU)/mL, Staphylococcus aureus > 104 CFU/mL and Enterobacteriaceae >104 CFU/mL. Pasteurization It should inactivate pathogens while limiting the impact on the milk's protective elements. The most common practice is the long-time (30 min), low-temperature (62.5°C) Holder pasteurization method. There are different devices to perform Holder pasteurization. As the exposition of milk to high temperature can alter immunological properties of milk, each pasteurizer should be qualified to be sure that the increase in temperature and the plateau are not too long, and that the cooling is rapid enough (13). It requires the presence of temperature probes in some of the milk bottles undergoing pasteurization. The number of probes and where they have to be positioned into the pasteurizers is not clearly defined by the manufacturers and were still not proposed until recently by some manufacturers. Higher-temperature methods of shorter duration, such as flash pasteurization (72.0°C for 5–15 seconds), may be more effective at retaining milk properties, but could be technically complex in HMBs that have to treat large amounts of DM each day. Each HMB must select a pasteurization method based on its resources. Other methods have been proposed (ultrasounds, high pressure) that could help to preserve nutritional and immunological properties of HM, but still have to be evaluated extensively (14,15). Post-Pasteurization Screening It can be used to monitor for contamination introduced after the pasteurization process or pasteurization failure. Some HMBs test each sample, whereas others test batches only on a designated schedule. Such heterogeneity in practices is due mainly to differences in resources. Safety of donor milk recipients is ensured by discarding milk if any microbial content is found. There is no consensus on the type of plates use to assess bacteriological content of milk, and whether a qualitative analysis is necessary or only a total bacteriological count. There are also some differences in the bacteriological criteria used to reject contaminated milk, for example, the cutoff values for the number of colony-forming units per milliliter above which the milk will not be accepted for donation. Testing for Nutritional Content of DHM In some places, nutrient content is assessed using mid-infra-red analyzers every 2 weeks or even each day to perform individualized targeted fortification (10,16). In most places it is not done due to a lack of resources or because there is not yet proven efficacy. Indeed, targeted fortification is a quite complex process requiring significant supplementary workload. That strategy has not proved higher efficacy than standard fortification, even if there are some indications from pilot studies that it could help (17). It is also crucial that clinicians support breast-feeding in preterm infants. The earlier these babies will suck efficiently from breast, the earlier the feeding tube and syringes will be avoided and it is crucial to avoid fat losses, which can be as high as 50% (18). Nutritional care of preterm infants should be comprehensive and include all parameters from the breast of the mother or donor to the digestive tract of the hospitalized baby. RECOMMENDATIONS Positioning the Human Milk Banks HMBs can contribute to develop an integrated system for providing optimal newborn care, together with other best practices for neonatal care (19). As it is part of the strategy aiming to provide HM to most of preterm babies it should be associated with hospital-based lactation program and OMM bank (20) and mother/baby centers for donor milk donation and lactation support (21). All these facilities should promote HM banking. Processes to Provide Safe, High-Quality Donor Milk Although there is not yet enough published data to provide evidence for each operational process required to provide safe, high-quality DHM, there are common points in the recommendations proposed in the different countries. Before ongoing research could support evidence-based recommendations, it could be propose to obtain the largest consensus based on the experience of existing HMBs in different countries. The main points that are still a matter of debate were presented above and should represent research priorities in the field of DHM expression, collection and processing. CONCLUSIONS HMBs are essential for providing safe DHM to vulnerable infants, such as VLBW infants. The collection, treatment and distribution of DHM require technical processes which are still differing depending on locations, organization and resources. Universal core requirements and quality principles for all HMBs are required. These are often based upon consensus between health professionals in each country. Further research is needed to help building universally accepted recommendations.