Background: Human milk is a dynamic biological fluid which promotes healthy growth and development among infants due to its nutritional, immunological, and bioactive properties. In human milk banks (HMB), holder pasteurization (LTLT, 62.5 °C for 30 min.) is a thermal method used for processing human milk. This conventional method of sterilizing human milk has led to some nutritional, physicochemical, and bioactive losses. Pulse light (PL) is an emerging non-thermal technology that uses high intensity light pulse on food surfaces and liquids for decontamination and sterilization. It uses an intense light pulse of short pulses with flashes in the wavelength ranging from 200 nm (UV) to 1100 nm (IR). There are currently no studies on the application of pulse light to human milk.
Aims: To compare the effect of pulse light and thermal treatment (LTLT) on the nutritional, physicochemical, antioxidant, and microbiological profile of human milk.
Narrative: Human milk samples were collected from a HMB in Mumbai and stored as per HMB protocol. Samples were collected and studied as approved by the Institutional Ethics Committee, Mumbai. The milk samples were thawed and processed with both LTLT (62.5 °C for 30 min) and PL (2.0–2.9 kV;10–30 s) treatment. In physicochemical properties, the human milk samples showed an increase in total soluble solids, total color change, and increased viscosity after PL treatment. However, pH was increased in LTLT treatment (mean pH = 7.29, SD = 0.03) compared to PL (mean pH 6.07, SD = 0.03). The microscopic images of human milk showed more breakdown of fat globules with aggregation after PL treatment. The nutritional properties of human milk showed significant differences (p < 0.05) in milk components like protein, fat, lactose, ash, mineral, and retinol content after both PL and LTLT treatment. The antioxidant activity of human milk was decreased in LTLT treatment compared to PL treatment. Among microbial reduction, significant log reduction in TPC (1.25 log CFU/ml) and LAB (1.44 log CFU/ml) was observed in PL treatment. PL (2.9 kV) showed a similar effect on microbial reduction like LTLT. Bioactives like Human IgA, lactoferrin, and lysozyme were better retained after PL but leptin was better retained in LTLT treatment.
Conclusion: Pulse light treatment on human milk had a better physicochemical profile, and there was greater retention of nutrients and bioactives than with thermal (LTLT) treatment. The present study gave preliminary and valuable results for pulse light treatment on human milk which could be used as an alternative to the conventional pasteurization method currently being used in human milk banks.
