Human milk bank and donor milk in Japan
Katsumi Mizuno MD, PhD
Abstract
With recent changes to the nutritional strategies for preterm
infants, early initiation (within 24 hours of birth) of enteral nutrition isbecoming a standard practice. Almost 30 years ago, there was amulticenter clinical trial revealing that the early initiation of enteralnutrition resulted in better growth during NICU stay, less chronic lungdisease incidence, and less necrotizing enterocolitis. However,mother’s own milk (MOM) was often not available, such that other
women’s milk (unpasteurized) was given to the infants. Some infants
ended up being infected by cytomegalovirus (CMV) or multidrugresistant bacteria. No matter how the early initiation of enteral feeding
is good for preterm infants, we were reluctant to use other women’s
milk due to the fear of infection. This is the major reason why we needhuman milk bank (HMB) in Japan. We can give DHM to the infants
according to the standardized enteral feeding protocol.
Finally, in Japan, the first HMB is established in 2017 after 3 years
of preparatory period and the amount of DHM delivered to NICUs
has increased with time.
I am going to talk three topics regarding HMB and DHM in Japan;
Firstly, I would like to share our experience about the first HMB inJapan.
Secondly, I would like to talk about lyophilization technique forfortification of mothers’ milk.
Lastly, we currently found microwave procedure (500W for 40 sec)
could inactivate human cytomegalovirus (HCMV), such thatmicrowave technique could be a convenient method to prevent HCMV
infection via breast milk.
1) The history of HMB in Japan
Based on the results of our 3 years of preparatory period whichwas supervised by the Ministry of Health, Labor and Welfare, weestablished Japanese Human Milk Bank Association (JHMBA) inMay 2017.
Recipients: At this moment, we offer DHM only to very low-birthweight infants. A total of 65 little? is given to 29 infants. Four babies
were born less than 500g. All the babies received DHM survivedand went home without serious problems. Needless to say, there
have been never any claims reported to DHM.
Donors: Since May 2017, there were 22 donors who clarified therequirements of being a donor.
Of which, 13 were mothers of preterm infants who admitted toNICU (NICU mom) and 9 were mothers of healthy term infants andregistered via website (Term mom). When we compared thebacterial tests of donated breast milk between NICU mom andTerm mom, we found that the breast milk from NICU mom contains
more diverse and morebacteria. From this experience, wethought we need to educate NICU mom repeatedly while they stayin the NICU with respect to clean expression methods?.
2) Fortification of MOM by lyophilized MOMWe asked if the lyophilized MOM could fortify MOM. Lyophilization isa well-established method for storing materials including food,medicine and vaccine. This method ensures no microbiologicalcontamination and preserves properties of the material in the vial. The
aim of this study was to determine whether lyophilization of humanmilk results in microbiological contamination and changes to thecomposition of human milk. In addition, we tested whether theaddition of lyophilized human milk (powder form) to the originalhuman milk (liquid form) could increase the concentration of major
nutrients in human milk.
Lyophilization preserved the nutritional and anti-infective componentsof human milk without increas in microbiological contaminants
observed. Additionally, as expected, the addition of lyophilized humanmilk to human milk (liquid form) increased its nutritional content.
3) Convenient pasteurization with microwave irradiation

The other research we have been working on is to pasteurize MOM
by microwave, mostly due to HCMV prevention. HCMV Towne strain
was added to formula, followed by heat processing using Holder
pasteurization (HP) or MW irradiation at 500 W for 20, 30, 40, or 60 s.
Addition of HCMV for a viral load of 5.0 × 103 plaque-forming units(pfu)/mL achieved 772 pfu/mL at baseline, with a decrease to 257
pfu/mL after 20 s. The number of plaques reached 0 after 30 s of MW
heat treatment. The number of HCMV DNA copies at baseline did notchange with 40 s of MW heat treatment, remaining between 2,017
and 2,157 copies/mL.
We confirmed that the decline of breast milk components, such asSIgA, lactoferrin
were less by MW, compared to Holder pasteurization.