Medela’s NICU solutions for human milk safety and infection control

By combining innovative products and knowledge, Medela strives to support hospitals in their attempt to optimise human milk processes. In this particular case, the focus is on infection control and safety in order to maintain the quality of human milk as much as possible until it is fed to the infant.

Hygienic collection of human milk

Milk can be contaminated at any point along the milk pathway when it comes into contact with foreign surfaces. In particular, contaminated pumps have been identified as reservoirs for bacteria, especially after being used by multiple mothers and cleaned inadequately between uses. Hygienic collection of milk should therefore begin prior to pumping:

  • Mothers should maintain normal maternal breast hygiene; no additional cleaning of the breast prior to milk expression is required
  • Mothers who use a breast pump are recommended to wash and dry their hands thoroughly prior to pumping
  • Hand drying with clean, single-use paper towels is regarded as best practice, in conjunction with turning taps off in a way that does not recontaminate the hands
  • Pumping mothers and especially healthcare personnel should keep their fingernails short and remove jewellery

Symphony breast pump system

Breast pumps and pump sets are potential carriers of pathogenic microorganisms. Every mother therefore needs her own pump set, consisting of breast shield, connector, valve head, valve membrane, bottle, tubing, membrane cap and protective membrane.

Medela’s milk overflow protection system

Medela Symphony breast pump with PersonalFit PLUS Pumpset

Medela’s Symphony breast pump system was developed to minimise the risk of contamination. Thanks to the innovative milk overflow protection system called media separation, a division is created between the pump and the milk thus preventing potential cross-contamination between mothers. This feature makes the Symphony a hygienic multi-user breast pump.

Firstly, Medela’s breast shields have a splash guard that guides milk flow directly into the collection bottle. Secondly, the protective membrane of the media separation is placed on the pump with the membrane cap. This protective membrane helps ensure that no milk can flow into the breast pump. The mother can simply take her complete pump set, including tubing and protective membrane and membrane cap, directly from the Symphony, leaving it ready for the next mother to use.

Collection containers and pump sets

Medela’s collection containers and pump sets are an integral part of the Symphony pump system. The choice of what collection containers and pump sets to use in the NICU depends on many factors, including national regulations, internal guidelines, sterilisation facilities and environmental considerations.

To accommodate the diverse needs of each hospital, Medela provides three types of collection containers and pump sets:

  • Disposable and Ready-to-Use
  • Disposable and sterile
  • Reusable

Disposable products

Medela disposable products are available as Ready-to-Use and EO sterile lines. They are intended for single- or one-day-use in hospitals, without the need for cleaning prior to first use. Disposable products are an attractive choice for hospitals that do not have the time, resources or infrastructure to process reusable products in large quantities or for which this is not economically viable.


Medela sign ready to use

Medela Ready-to-Use products are hygienically safe to use without prior cleaning (Deutsches Beratungszentrum für Hygiene, 2014).


Medela sign sterile

Medela sterile products are validated according to the applicable EN/ISO standards for sterile medical devices. ‘Sterilised’ or ‘pre-sterilised’ products are not to be confused with ‘sterile’ products. Only the term and symbol ‘STERILE’ guarantee that the product is actually sterile.

Reusable products

For hospitals with sterilisation processes in place, Medela offers autoclavable pump sets and bottles. These can be used by multiple mothers after sterilisation between users. For hospitals with validated cleaning processes, equipment and personnel in place, Medela’s reusable products may be a good option, economically as well as ecologically.

To assess your priorities and what option works best for you, please contact your local Medela sales representative.

Breast shields and containers: adaptable to all needs and processes

Breast shields for the hospital are available in different sizes to cater to the needs of all mothers.

Medela disposable bottles 250ml 150ml and 80ml

Medela collection containers have grading in small and precise volume increments so that the quantity of expressed breast milk can be checked accurately and easily. They are available in a range of different sizes, from 35ml to 250ml.

The Medela disposable Colostrum Container has been developed with healthcare professionals and mothers in mind. The container is designed for carefully dealing with small volumes of breast milk. The curved bottom allows the user to easily draw milk from the container into a syringe. With this ease of extraction, the chances of contaminating the milk during handling can be minimised.

Medela breast milk bottles, storage containers, feeding products and breast pump kits are made from food-grade materials that are BPA free.

Hygienic handling and storage practices

Hygienic practices after pumping are just as important as those that occur prior to and during pumping. To minimise the chances of bacterial growth and infection, the following actions should be undertaken after pumping:

  • External surfaces of hospital breast pumps and kits, particularly those touched by mothers or staff, should be disinfected with solutions or wipes between users.
  • The surface upon which cleaned pump set parts are placed should also be disinfected with solutions or wipes.
  • Pump set parts that come into contact with milk should be completely separated and thoroughly cleaned after each use. They should be rinsed in cool water to remove milk residue, then washed with washing-up liquid and water, either under running water or in a clean bowl designated solely for this purpose. Patient-specific bottle brushes can be used to clean parts, especially tight crevices.
  • After washing, parts should be rinsed thoroughly and then placed on a disinfected surface for drying. Clean cloth towel-drying may be acceptable, or air-drying is another option. Once clean and dry, pump set parts should be removed from the sink area to prevent contamination from splashback of the sink.

In the NICU there is a requirement to transfer and store pumped milk. This comes with the potential hazard of nutrient loss and contamination. The NICU must optimise storage conditions to minimise the loss of nutrients, growth factors and many other protective components in milk, whilst also minimising the possibilities of contamination at the NICU or mother’s home. With both time and varying temperatures, components in human milk decrease in potency while the growth of pathogens increases.

Providing the right milk to the right infant

Appropriate labelling is one of the prerequisites for safe storage. Methods such as storage boxes for each individual mother that are kept in a freezer or fridge, as well as bar codes more commonly seen in milk banks, may also be advantageous. Similar to the handling of other critical fluids in the hospital, the four-eyes principle has been recommended for the distribution of human milk to infants.

Pre-printed labels

Medela’s pre-printed labels help to ensure traceability. Medela labels request the following data:

  • Name of the infant
  • Date of expression
  • Time of expression
  • Quantity of expressed milk

This information helps to bring the milk from the mother to her own infant in the correct order. Moreover, it provides the exact volume, which can be difficult to assess if the milk container was not upright during freezing.

Labels help to follow the general rule of using fresh milk where possible and exposing the infant to colostrum first. This follows the first-in-first-out (FIFO) principle, whereby the milk expressed first should be fed first if fresh milk is not available.

Appropriate storage

Human milk should be refrigerated or frozen as soon as possible if it is not to be used within four hours of expression. Each hospital should have policy recommendations for mothers about storage containers, conditions and times as well as specific recommendations that differentiate between donor milk and own mother’s milk, especially when fortifier has been added. Mothers transporting milk from home to hospital should be instructed on how to keep milk cool during transport with cooling bags.

Storage guidelines for human milk in the NICU

Guidelines for storing and thawing milk will differ according to the environment and the medical condition of the infant. In all instances, storage times should be kept as short as possible. The following recommendations are research-based and cover the human milk pathway in the NICU.

Pasteurisation and the use of donor milk

Pasteurisation is a process commonly utilised to reduce bacterial load and to eliminate viruses that may be passed from the mother to the milk. When milk from an infant’s own mother is either not available or not acceptable in a NICU setting, pasteurised donor human milk is the next best option. The downside of current pasteurisation processes is the loss of some immunological and nutritional components. The loss of the anti-infective activity of human milk means that the bacterial growth rate of pasteurised human milk is higher than in untreated human milk.

Medela offers bottles that can withstand pasteurisation temperatures and are suitable for the milk volumes handled in centralised milk kitchens or milk banks. In addition, the multi-user Symphony breast pump system, with its hygienic pump sets, serves as a partner for the collection of milk from donors.


Due to the high nutritional demands of preterm infants, fortification is recommended for those born weighing less than 1500g. Despite the benefits of fortification, bacterial growth in milk stored at refrigerator temperature is significantly greater in fortified milk compared with unfortified milk. Milk storage recommendations are therefore impacted.

The addition of fortifiers using aseptic techniques at room temperature or lower has been suggested to help minimise changes in osmolality levels.

Safe, hygienic and gentle warming of human milk

The thawing and warming of human milk are the final stages of preparing milk for feeding. Controlling the temperature of milk is not only important for maintaining its integrity, but may also be beneficial for the high-risk infant. Fluids such as saline and blood are usually warmed prior to infusion in order to avoid decreases in infant body temperature. In line with this, it has been theorised that milk temperature can also impact infant body temperature. Therefore, warming neonatal feeds has become a common practice in many NICUs, with the idea that feeds warmed to body temperature may improve infant outcomes, such as the infant’s ability to tolerate gavage feeds.

Water-based methods have been used for both thawing and warming human milk. These usually involve placing bottles or containers of milk in water baths or water-filled containers that should not exceed 37 °C. Regulating and achieving optimal temperature with these various water-based methods is challenging. Additionally, water, particularly when warm, can harbour pathogens.

Historically, contaminated hospital tap water used in bottle warmers has been identified as a source of nosocomial infection and outbreak in the NICU. Consequently, some NICUs now use dry, waterless warmers such as Medela’s Calesca.

Medela offers Calesca, a waterless warming and thawing device that helps optimise and standardise human milk processes and minimise the challenges associated with human milk handling. Designed for individual care in the NICU, Calesca aims to maintain the integrity of human milk by warming it towards body temperature without exposing it to high temperatures.


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