The particular benefits of human breastmilk for preterm and term infants have been well described in medical literature . Human milk provides important nutritional components, digestive enzymes, immunological factors, growth factors, and hormones that make it a clinical standard of care for preterm (including very low-birth-weight) and term infants . The beneficial effects of human milk (fresh and pasteurized) on rates of pediatric infection such as necrotizing enterocolitis (NEC) and sepsis have also been clearly demonstrated [3–5]. Donor breastmilk has been encouraged as the milk of choice when a mother's own breastmilk is not available due to illness/infections, medications, or other social reasons . Using human milk is of particular importance for preterm infants of HIV infected mothers as early introduction of formula feeds could be the source of allergens or contaminants. These allergens/contaminants in such an immature infant could provoke gut epithelial damage and therefore put the child at increased risk of breastfeeding transmission [7–9] once breastfeeding commences. Research from the United States indicates that even if donor milk is only half as effective as mothers' own milk in reducing infection and NEC in newborn infants, providing donated pasteurized breastmilk in a neonatal clinical setting is still more cost-effective than relying on preterm formula .
Because of the well documented benefits of donor breastmilk, a donor breastmilk bank was set up in the Neonatal Prem unit (NPU) of King Edward VIII Hospital (KEH) in Durban, South Africa at the beginning of 2009. KEH is a public hospital that serves a disadvantaged community and its NPU has an average intake of 180 infants per month. As part of the routine protocol in the NPU all mothers of HIV unexposed infants are encouraged to provide breastmilk to their infants. HIV infected mothers are routinely counseled on appropriate infant feeding for their situation according to WHO guidelines. HIV infected women who opt to breastfeed are taught how to heat treat their own expressed breastmilk (HTEBM) before they feed it to their infants. The new breastmilk bank that was opened a few months prior to the commencement of this evaluation study operates under the guidelines of the Human Milk Banking Association of South Africa (HMBASA) . As it is unlikely that there will ever be an unlimited supply of donor milk, each child is assessed for their eligibility to receive donor milk. Preterm/low birth weight infants whose mothers are not able to supply their own milk are eligible to receive donor breastmilk if they are HIV infected and/or if they are at risk of NEC. The duration of donor breastmilk given to an infant depends firstly on the availability of donor breastmilk supplies and secondly, on the child's condition as assessed by the NPU doctor in charge. Donor mothers are sourced from the NPU and obstetric wards of KEH and they are healthy, HIV negative women (determined on 2 separate HIV tests) who are screened for absence of any lifestyle risks. All donor mothers in the unit use hand expression to express breastmilk into a 250 ml sterile glass jar which is then pasteurized by a breastmilk bank assistant, rapidly cooled and then decanted into a smaller sterile glass jar for storing. Following HMBASA guidelines, post-pasteurisation, an aliquot of milk is removed from the first donation of each new donor and is tested for microbial contamination. Each donor is given a donor number which is recorded on the bottle of milk together with the date of expression. Donor breastmilk is kept frozen in a -20°C chest freezer for up to 3 months after expression. Because the concept of donation of breastmilk was new in the hospital, when there were periods of insufficient supplies the breastmilk bank also sourced pasteurized donor breastmilk from a nearby NGO run community based breastmilk bank. This NGO run milk bank uses the same donor screening and bacterial screening practices, the only difference is that the milk is pasteurized by the Holder Pasteurisation Method using an automated commercial pasteurizer (Sterifeed S90).
Implementing a milk bank in this resource-poor setting presented multiple challenges particularly because of inadequate staffing and lack of funds for maintenance of equipment. Therefore a decision was made to use a method of pasteurization that would be more appropriate within these limitations. This pasteurization method, known as flash-heat, is a simple method which involves heating individual jars of breastmilk in a water bath. Flash-heat mimics commercial high-temperature short-time (HTST) pasteurization. This 'low-tech' method of pasteurization, has been documented to inactivate cell-free  and cell-associated HIV ; destroy pathogenic and non-pathogenic bacteria  and preserves the vast majority of vitamins , immunoreactive proteins and immunoglobulins .
There is skepticism among health care workers and policy makers in South Africa around feasibility and safety of human milk banks in this area mainly because of the fear of HIV transmission and the cultural acceptability. These concerns have severely hampered the use of donor breastmilk and there is therefore an urgent need for this information from South Africa to clarify these issues. This study hopes to provide some of this information which is in keeping with a resolution passed during the 61st World Health Assembly Meeting in Geneva (May 2008) calling on the World Health Organization to support countries to conduct research on the feasibility of implementing breastmilk banks. There have been no prospective studies in South Africa examining the feasibility or safety of donor breastmilk supplied by breastmilk banks in NPUs. However there has been a report of anecdotal data suggesting that it was feasible and safe to provide donor breastmilk to infants during an outbreak of rotavirus .
The objectives of this study were twofold. First, we sought to address feasibility by documenting whether the medical staff would prescribe donor milk for infants; and whether eligible mothers in the unit would be prepared to donate breastmilk to the bank. We also investigated the feasibility of adhering to the HMBASA quality assurance guidelines for microbial testing of breastmilk. Secondly we sought to evaluate an aspect of the safety of providing donor milk by documenting clinical adverse events of infants fed on donor milk compared to formula milk. We did not seek to investigate whether infants fed on donor milk had a better outcome than those fed on formula milk as this has already been established as concluded in a Cochrane Review .