Ultraviolet-C Irradiation: A Novel Pasteurization Method for Donor Human Milk.

Lukas Christen,Ben Hartmann,Peter E Hartmann,Ching Tat Lai,Donna T Geddes,John R Battista

doi:10.1371/journal.pone.0068120

Abstract

BackgroundHolder pasteurization (milk held at 62.5°C for 30 minutes) is the standard treatment method for donor human milk. Although this method of pasteurization is able to inactivate most bacteria, it also inactivates important bioactive components. Therefore, the objective of this study was to investigate ultraviolet irradiation as an alternative treatment method for donor human milk.MethodsHuman milk samples were inoculated with five species of bacteria and then UV-C irradiated. Untreated and treated samples were analysed for bacterial content, bile salt stimulated lipase (BSSL) activity, alkaline phosphatase (ALP) activity, and fatty acid profile.ResultsAll five species of bacteria reacted similarly to UV-C irradiation, with higher dosages being required with increasing concentrations of total solids in the human milk sample. The decimal reduction dosage was 289±17 and 945±164 J/l for total solids of 107 and 146 g/l, respectively. No significant changes in the fatty acid profile, BSSL activity or ALP activity were observed up to the dosage required for a 5-log10 reduction of the five species of bacteria.ConclusionUV-C irradiation is capable of reducing vegetative bacteria in human milk to the requirements of milk bank guidelines with no loss of BSSL and ALP activity and no change of FA.

Highlights

Human milk contains nutritional and bioactive components that cannot be provided to the infant by formula milk
Bacteria analysis Exponential reductions of E. coli, S. epidermidis, E. cloacae, B. cereus and S. aureus were observed after irradiation with UV-C light (Figure 2)
In an overexposure experiment were the human milk was treated significantly longer than needed to reduce the microbial load by 5-log10 we found a significant exponential decrease (p = 0.004) in alkaline phosphatase (ALP) activity

Summary

Introduction

Human milk contains nutritional and bioactive components that cannot be provided to the infant by formula milk. Human milk is heated in a water bath and held for 30 minutes at 62.5uC [3,4,5] This treatment is capable of a 5-log reduction of bacteria including Escherichia coli, Staphylococcus epidermidis, Enterobacter cloacae, Bacillus cereus and Staphylococcus aureus in human milk [6]. This process results in the alteration and the loss of activity of important bioactive components. Studies have shown that preterm infants fed pasteurized human milk have a lower fat absorption and growth rate compared to preterm infants fed raw milk [11,12] Another enzyme completely lost with Holder pasteurization is alkaline phosphatase (ALP). The objective of this study was to investigate ultraviolet irradiation as an alternative treatment method for donor human milk

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Methods

Results

Discussion

Conclusion