Bacterial contamination of bottle milk in infants under 6 months in children's hospital, Bangkok, Thailand

Abstract

The bacterial contamination of bottle milk samples obtained randomly from 500 infants under 6 months of age who came to the Out-patient Department of Children's Hospital Bangkok was determined by collecting bottle milk samples prepared at home following interview of their caretakers after obtaining their consent. Bacterial contamination was found in 91.8% (459/500) of bottle milk samples. Among the positive samples, 82.8% (380/459) contained enteric bacteria, another 17.2% were unidentified bacteria. The dominant enteric bacteria isolated from bottle milk were Klebsiella spp (56.6%), Enterobacter spp (41.3%), Aeromonas spp (14.4%), E. coli (13.4 %) and Vibrio cholerae non O-1 (1.8%). Isolated E. coli were further identified as enteropathogenic E. coli (7.8%, 4/51) and enterotoxigenic E. coli (3.9%, 2/51). About 74% of the contaminated bottle milk contained one type of bacteria, 23.7% had two types and 2.3 % had 3 or more types of bacteria. A level of bacterial contamination greater than the US government limited number (USGLN 2x104 CFU/ml) was found in 86.4% of total examined samples (432/500) [geometric mean (GM) of 2.9 x 106 CFU/ml]. About 66% (333/500) of bottle milk samples had coliforms greater than the USGLN (1 x 102 CFU/ml) with GM of 1.3 x 104 CFU/ml. Therefore, in the preparation of bottle milk, feeding practice should be emphasized in every setting of maternal-child health care and promotion of breast-feeding should be encouraged by the health personnel.