Bacterial Load in Expressed and Stored Breast Milk of Lactating Mothers in Abia State, Nigeria

Abstract

The use of expressed breast milk has been advocated as an effective way of encouraging and maintaining lactation when the mother is separated from the baby for a while. However, prospects of storage of expressed breast milk for any considerable period of time is hindered by the possibility of bacterial contamination and growth of infectious pathogens in the stored milk. Previous research worldwide has focused on optimal conditions for storing expressed breast milk. This study investigated bacterial growth in expressed breast milk stored at two different conditions and time periods. A total of 240 randomly selected lactating mothers participated in a survey used to elicit information on their practices concerning expressed and stored breast milk. Out of this, 20 lactating mothers were willing to donate their breast milk, which was used for microbial studies. Using antiseptic procedures, breast milk samples were collected from these 20 lactating mothers by manual expression and put into sterile containers. One half was stored at room temperature (30^oC), while the other half was immersed in a container of water (26^oC) for 0, 3, 6 and 9hrs. The samples at different time periods in both storage conditions were plated on three different culture media (Nutrient agar, MacConkey agar and Chocolate agar) and incubated for 24hrs. Bacterial load was enumerated and isolates were characterized and identified. Data was analyzed using one way ANOVA and presented as frequencies, percentages means and standard deviations. Results showed that in all the culture media, bacterial load was higher in breast milk samples stored at room temperature for up to 9hrs compared to that immersed in water (p<0.05). However, the average colony counts were within acceptable limits (<10⁴CFU/ml). Enterococcus faecalis, Escherichia coli and Staphylococcus aureus were the predominant bacteria isolated in the breast milk samples under both storage conditions. The findings from this study revealed that storage of breast milk either at room temperature or immersed in a container of water appeared to be safe for up to 9 hours of storage in a tropical environment. Generally, the number of microbes was within levels considered acceptable in expressed breast milk.

Key words: bacterial growth, expressed, breast milk