Assessment of Dornic acidity in breast milk based on storage time in the freezer and place of expression.

Introduction. The degree of Dornic acidity (DA) is an indirect measure of milk contamination and quality. In freshly expressed milk, DA ranges between 1.0 and 4.0 (optimal). If DA is > 8.0 °D, it should be discarded. The correlation between DA in raw breast milk from internal donors (ID) and external donors (ED) based on storage time until pasteurization was assessed. Population and method. Retrospective, analytical study. Results. In 13 203 samples, DA was lower in IDs as of 14 days of storage: 2.92 (95% CI: 2.69-3.15) versus 4.01 (95% CI: 3.94-4.08), with a higher proportion of DA ≤ 4 °D (88% in IDs versus 76% in EDs); odds ratio: 2.30 (95% CI: 1.25-4.24). Conclusion. DA as of 14 days of storage was lower in IDs, with a higher prevalence of DA ≤ 4 °D. No correlation was observed between storage time and DA in ID samples.