Efficacy of locally-available cleaning methods in removing biofilms from taps and surfaces of household water storage containers

Abstract

Biofilms are aggregates of microorganisms attached to surfaces that can (re)contaminate water by releasing microorganisms. We grew E. coli biofilms on household taps and on storage container coupons, and cleaned them with locally-available agents (bleach, boiled water, soapy water, vinegar) and methods (flowing, scrubbing, or soaking taps; soaking and wiping container coupons). After cleaning, we enumerated surface E. coli and imaged biofilms using epifluorescence microscopy. Biofilms were removed from taps when: soaking assembled for five minutes (bleach, boiled water); and, scrubbing and soaking unassembled for five minutes (bleach, boiled water, vinegar). Only soaking methods removed E. coli from container coupons. To remove biofilms, we recommend soaking assembled taps in boiled water for five minutes. No recommendation for cleaning containers emerged as soaking storage containers is impractical. Results are consistent with biofilm research, and highlight the need for technical research to develop realistic cleaning recommendations for water storage containers in households.