Effect of different methods of pasteurization on bactericidal action of human milk: A prospective observational study

BACKGROUND & OBJECTIVES: Pasteurization involves not only inactivation of pathogens, but also loss of immunological functions and bactericidal action of human milk. Hence, this study was aimed to explore the stability of such bactericidal action after subjecting human milk samples to thermal pasteurization under different condition of time and temperature. METHODS: In this observational study 48 human milk samples were analyzed over a period of three months. The effect of holder and flash methods of pasteurization on bactericidal action against Escherichia coli was evaluated compared to the control sample before and after 72 h of storage at −18°C. RESULTS: Both holder and flash methods of pasteurization showed significant reduction in the E. coli growth to 46.4 and 25.5 per cent, respectively, after 24 h of incubation (P<0.001). The bactericidal activity was significantly more in samples subjected to holder method compared to flash method before and after 72 h of storage (46.41±15.38 vs. 25.50±30.74, P<0.001 and 42.27±20.38 vs. 18.33±28.55, P<0.001). INTERPRETATION & CONCLUSIONS: Our results showed that the bactericidal activity of human milk was better preserved by the holder method of pasteurization. Further well-powered and well-designed randomized trials are needed to confirm the findings.