Efficacy of protocols for cleaning and disinfecting infant feeding bottles in less developed communities

Background. While breastfeeding is the best choice for most infants, national programs include provision of free infant formula as part of the strategy to prevent mother-to-child transmission of HIV in several less developed countries. An additional, unknown number of parents use infant formula for other reasons. Infants are commonly fed formula in bottles that can be difficult to clean. Several alternatives to boiling are available for disinfecting water used to prepare infant formula; however, few low-cost alternatives are available for disinfecting infant bottles in settings without reliable access to electricity, potable water, and cooking fuel. Methods. We artificially contaminated infant feeding bottles with low (~10³ colony-forming units [CFU]/ml) and high (~10⁶ CFU/ml) inocula of a mixture of Salmonella and enteropathogenic Escherichia coli strains. We evaluated the laboratory efficacy of several cleaning and hypochlorite disinfection protocols. Results. The most efficacious cleaning method examined was rinsing with soapy water followed by tap water; it reduced pathogen load by 3.7 and 3.1 log₁₀ CFU/ml at the low and high inoculum levels, respectively, compared with controls. The optimal disinfection method involved submersion in 50 ppm hypochlorite solution for 30 minutes, which resulted in no identifiable pathogens among bottles contaminated with high inocula. This equated to a 3.7-log₁₀ CFU/ml reduction in pathogens and was comparable to boiling. Conclusions. When combined with handwashing, use of safe water, and appropriate storage of prepared infant formula, these simple, inexpensive practices could be a useful option for improving the microbiological safety of infant formula feeding in less developed settings.