716 BACTERIOSTATIC QUALITIES OF HUMAN MILK

Abstract

We have previously reported no increase in bacterial colony forming units/ml (BCFU/ml) in human milk(HM) after 48 hours of refrigeration. The bacteriostatic quality of HM without the benefit of refrigeration is a practical concern of working mothers. Therefore, we investigated the relationship between the number of BCFU/ml of milk vs timed room temperature (19-26°C) incubation (storage). Quantitative cultures of milk stored at room temperature were performed at 0, 2, 4, 6 and 24 hours post expression. Milk from 10 mothers less than six days postpartum (colostrum) and from 10 mothers 7-42 weeks postpartum (mature milk) was studied. a=hours room temperature incubation; b=BCFU×103; c=p<.005 The number of BCFU/ml at 0 time did not significantly increase in mature milk after 6 hours nor in colostrum after 24 hours of storage at room temperature. However, the BCFU/ml in mature milk was significantly greater (p<.005) at 24 hours than after 0 and 6 hours of incubation. Thus, mothers who express milk at work for their own infants may assume that the bacterial contamination of their milk will not increase significantly for up to six hours post expression even if they have no access to refrigeration.