03/09/2026
New study on offering a bottle of human milk or formula again at the next feeding:
"We therefore explored, for the first time, bacterial loads in leftover milk stored at room temperature. A maximally conservative reading of our data supports the hypothesis that such milk could be safely fed to infants up to 4h post initial feeding, which is the timeframe most likely practically relevant for care givers. . . . Under the conditions tested, leftover formula and human milk showed minimal bacterial growth over clinically relevant timeframes, suggesting that current discard recommendations may be more conservative than necessary for healthy, full-term infants in home settings."
Importance Current guidelines from the World Health Organization, Centers for Disease Control and Prevention, and Academy of Breastfeeding Medicine recommend discarding all milk remaining in bottles immediately after infant feeding. However, these recommendations lack supporting microbiological evid...
