Bacteriology of unheated expressed breast milk stored at room temperature

Abstract

Thirty samples of unheated expressed breast milk (EBM) from 30 lactating mothers, and twelve samples of unboiled Kenya Co-operatives Creameries (KCC) milk, both stored at room temperature (RT) and in the refrigerator (at 40C), were examined for the degree of bacterial contamination at o hour, 4 hours, 6 hours and 8 hours. All the EBH samples were contaminated at 0 hour. The mean bacterial colony counts was 5.438 x 103 c.f.u/mm3 with a range of 0.15 - 23.1 x 103 c.f.u./mm3• Pure cultures were obtained in 12 out of 30 (40%' while 18 out of 30 (60%) had mixed growth. The majority'of the bacteria found in EBM were skin flora like Staphylococcus albus 76.7% (23/30) ~~d streptococcus viridans 40% (12/30).· Potential pathogens like Escherichia coli, Streptococcus faecalis and Staphylococcus aureus ~ere found in 26% (8/30), 13.3% (4/30) and 6.7% (2/30) respectively. Three out of eight (37.5%) of the Escherichia coli were of faecal origin. Eleven out of the twelve KCC milk samples had bacterial contamination at o hour. One sample was sterile. The mean bacterial coiony -courrt s was'77.8 x 103 c.f.u./I)lIlwli3th a range of 45 - 103.5 x 103 c.f.u. / mm.3 Staphylococcus ..albus was isolated from 5 samples (4J.7%), Escherichia coli from 8(66.7%) and Anthrocoids from 8 samples (66.7%). All the Escherichia coli isolated froin.KCC milk were of non faecal origin. The bacteria grown from each sample at 0 hour was the same bacteria isolated at 4,6 and 8 hrur-s , There was no significant cha~ge in bacterial colony counts in EBM on storage at RT and at +4oC for 8 hours, p ,0.5 while signi£ icant rise in bacterial colony COQ~ts occurred in KGG milk stoored at RT for 6 hours (P£O.OS) and 8 hours (pLO.02). There was significant difference in bacterial colony counts in EBM and KeC milk both stored at RT at 0 hour (p L O. 01), 6 hours (p e: 0.01) and 8 hours (p L.0;00 1), but no significant difference in bacterial colony counts in EBM stored at RT and that stored in the refrigerator for 8 hours (P70.5)•