Sometime ago, someone on LACTNET asked about the implications of the article in Pediatrics (97:492-98, 1996) by Hamosh, etal re: the storage of human milk. Briefly-for those who haven't read it yet-the article reported on the results of storage of human milk (fresh, refrigerated) over time, and bacterial growth and other changes that might have occurred in the milk. Hamosh and colleagues sought to answer two questions: a) how stable are milk nutrients over time? and b) What bacterial growth occurs without cold storage? They used two groups of women, those who expressed their milk at home and those who did so in the hospital (usually because they had sick/premie infants). Key finding: Mothers who expressed in the home rather than the hospital were very likely to obtain milk that was not contaminated by bacteria. There was *almost no growth* in then first 24 hours if pumped and stored at home at 15°C (refrigerated temp, I believe). Bacteria were confined to staph epi in home expressed milk. If the mothers were expressing and storing in the hospital, a-strep and b-coliform was found in the milk. Proteins changed little with expression and storage, but fats concentrated rapidly. The authors therefore suggested that storage should be for 4 hour periods or less! Personally, I question this, after having worked for many many years with mothers who have stored milk for periods far longer than 4 hours. Note as well that this limitation is for milk that is stored at 38°C. Unless I am converting incorrectly, that is HIGHER than normal body temperature! (Please correct me if I am wrong on this). Most women do not work in settings with a room temperature in the 90°s! Milk that has been expressed at body temp is not going to remain at that temperature if in a container in a room that is not that warm. If placed on ice, that too is going to reduce the temperature of the milk, as would refrigeration or freezing. I consider this study to be helpful insofar as it notes minimal protein changes and the differences in "cleanliness" of the milk when expressed at home as opposed to a hopsital, but it does not answer those same questions for work sites other than a hospital NICU, nor does it acknowledge that most women do not operate in a room temperature lower than body temperature. We still need to determine how fats change in settings other than the breast. Anyone planning a study in an effort to answer these questions needs to attempt to replicate "typical" work settings that women inhabit for several hours a day. Consider this a hint! Def. of LC service: "We are all faced with a series of great opportunities brilliantly disguised as impossible situations." Kathleen G. Auerbach,PhD, IBCLC (Homewood, IL)- [log in to unmask] WEB PAGE: http://www.mcs.com/~auerbach/lactation.html LACTNET archives http://library.ummed.edu/lsv/archives/lactnet.html