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Updated: May 9, 2026
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Individualized Reconstitution of Human Milk Microbiota: A Feasible Approach in Real-World Settings
Published on: February 7, 2025
Recovering viable bacteriophages from human milk: implications for sample storage and processing
Ranran Li1, Julianne Megaw1, Natalie S Shenker2
1School of Biological Sciences and Institute for Global Food Security, Queen's University Belfast, Belfast, BT9 5DL, United Kingdom.
Journal of Applied Microbiology
|May 7, 2026
Summary
Viable bacteriophages are not found in human milk stored for 12 months at -20°C. Long-term storage at -80°C preserves bacteriophage viability better than -20°C.
Area of Science:
- Microbiology
- Food Science
Background:
- Molecular methods detect bacteriophage diversity in human milk, but not viability.
- Donor human milk undergoes processing (freeze-thaw, heat treatment) affecting viability.
Purpose of the Study:
- Isolate bacteriophages from frozen human milk.
- Evaluate sterilization and storage effects on bacteriophage survival.
Main Methods:
- Bacteriophage isolation from 20 frozen human milk samples.
- Artificial inoculation of milk/water with E. coli phage T4.
- Exposure to UV-C, Holder, and HTST pasteurization.
- Storage at different temperatures (-20°C, -80°C, 4°C, room temp).
Main Results:
- No viable bacteriophages found in milk stored 12 months at -20°C.
- UV-C irradiation significantly inactivated E. coli phage T4, especially in skimmed milk.
- Holder and HTST pasteurization had no significant effect on phage viability.
- Phage T4 better preserved at 4°C vs. room temp over 48 hours.
- Viability after 90 days: -80°C (31.6%) vs. -20°C (9.4%).
Conclusions:
- Prioritize fresh human milk samples for bacteriophage isolation.
- For short-term storage (up to 48 hours), use refrigerated temperatures.
- For long-term storage (up to 3 months), -80°C is preferable to -20°C.
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