16S survey of human milk
Freshly expressed milk samples (n=10) were collected and analysed immediately, stored at 4C for four days, -20C for 2.25 months and 6 months, and -80C for 6 months. Samples were analysed using propidium monoazide (PMA; a cell viability dye) coupled with full-length 16S rRNA gene. An aliquot of each sample was additionally analysed without PMA to assess the impact of cold storage on the total DNA profile of human milk.