Unhelpful old wives' tales
You'd think that in this modern age where we can test, measure and analyze the tiniest cells and bits of bacteria, we'd provide mothers and babies with the data they need for health and happiness. Unfortunately, as we have worked to bring Ceres Chill to the world, we have uncovered tedious and unsupported breastmilk "rules" that complicate an already challenging process for pumping mothers.
Most recently we have looked to science to tell us whether there is any support for the widespread belief that moms cannot add warm, freshly expressed milk to chilled milk.
Every time I encountered this rule, I thought, Why not? What happens if they add it? No-one could ever answer this question for me and there were never any research citations available. That really nagged at me as a pumping mom with a ton of work and barriers to breastfeeding already on my plate. I had friends throwing away ½ to 2 ounces at a time because they felt the amounts were too small to go through the process to pump, save, chill and then combine.
Lisa M. Stellwagen, MD, FAAP Pediatrics (Primary Specialty) | Newborn Hospital Care
The truth about combining warm and chilled milk
I'm happy to report that real research by doctors in this field tells moms something great: not only can you add warm milk to chilled, doing so has health benefits for your baby!
Enter Lisa Stellwagen, MD, a newborn specialist and board-certified pediatrician. Dr. Stellwagen has been a pediatrician for 30 years, both in community and hospital settings, and is the medical director of the Newborn Service at UC San Diego Health. Her clinical expertise includes infant nutrition, breastmilk feeding, and medical care of newborns. According to Dr. Stellwagen and her colleagues:
Hospitals have traditionally recommended that milk from each pump session should be individually stored, but this approach has not been validated. Furthermore, the merits of 24-hour pooling of mother's own milk have not been examined in the clinical environment. We found that a single daily pooling strategy provides several important benefits— consistent nutrient quality, equivalent bacterial content, and improved maternal satisfaction—over individualized collection.
Lisa M. Stellwagen, Yvonne E. Vaucher, Christina S. Chan, Taylor D. Montminy, and Jae H. Kim,
Breastfeeding Medicine Vol. 8, No. 2, published April 10, 2013