PD897 - PROLONGED STORAGE OF RAW HUMAN MILK: A LONGITUDINAL ANALYSIS OF PHYSICOCHEMICAL AND MICROBIOLOGICAL QUALITY

PD897

PROLONGED STORAGE OF RAW HUMAN MILK: A LONGITUDINAL ANALYSIS OF PHYSICOCHEMICAL AND MICROBIOLOGICAL QUALITY

D. S. N. da Silva¹, M. S. F. Lavrador¹, T. M. Miola^1,2,*, A. M. P. Lottenberg^1,3

¹Hospital Israelita Albert Einstein, ²Nutrition, ACCamargo Cancer Center, ³Laboratório de Lípides Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil

Rationale: The Brazilian protocol (ANVISA) recommends a maximum of 15 days for frozen storage of raw human milk (RHM), whereas international guidelines allow longer periods (3–6 months). This study evaluated whether prolonged household freezing affects physicochemical and microbiological quality of RHM, focusing on acidity, energy content, and coliform occurrence.

Methods: Prospective cohort study including RHM samples from 28 lactating individuals. Samples were collected under domestic hygiene conditions, stored in a household freezer (–18°C), and analyzed on days 1, 15, 30, 60, 90, 120, and 150 post-collection. Titratable acidity was determined by Dornic method (ºD), energy content by crematocrit (kcal/L), and coliform detection by presumptive testing in BGBL broth. Continuous variables were analyzed using generalized mixed models, while coliform frequency was assessed using Fisher’s exact test. Statistical significance was set at p<0.05.

Results: Acidity increased progressively over time (p<0.001), from 3.88ºD (95%CI: 3.04–4.71) on day 1 to 12.83ºD (95%CI: 11.18–14.48) on day 150. The 8ºD limit (Brazilian rejection criterion) was reached after 60 days (mean:7.57ºD; 95%CI: 6.83–8.82). Storage time did not affect energy content (p=0.116), remaining stable. Coliforms were detected in 5.9% of samples, occurring sporadically and without persistence over time. Contamination was not associated with storage time (p=0.126), increased acidity (p=0.33), or energy variation (p=0.13).

Conclusion: RHM stored at -18°C for up to 150 days maintained microbiological safety and stable energy content. Acidity was the limiting parameter, remaining within the Brazilian standards for up to 60 days. These findings support extending recommended storage beyond 15 days, as a safety practice and supporting breastfeeding continuity.

Disclosure of Interest: None declared