Bacterial growth in personal stainless steel water bottles

how often should you clean your bottle?

Abstract

Background: There is a general understanding and knowledge among reusable personal water bottle users that there are hazards, such as bacterial growth, associated with poor water bottle hygiene practices. Currently, there is no information associated with outbreaks or cases of illness stemming from poor hygiene on personal water bottles. This may be due to lack of awareness that users have become ill from their own water bottle and have failed to report it. Results from previous studies on personal water bottles have indicated that there is a relationship between higher microbiological counts and the interval between cleaning times; the longer water bottles are left unclean, the higher the microbial count. Methods: 29 randomly sampled stainless steel personal water bottles were swabbed at the mouth piece and 1 brand new personal stainless steel bottle was used as a control. Personal water bottle users were provided with an in-person electronic survey at the time of sample collection. The swabs were plated following the 3M Aerobic Plate Count method and incubated for a total of 72 hours. Plates were counted after 24 hours and 72 hours. Results: There was no statistically significant difference between the aerobic bacterial levels (CFU) of personal stainless steel water bottles that were cleaned within one day and those cleaned within a month but more than one day based on the Independent Sample T-test. There was also no statistically significance difference between the aerobic bacterial levels (CFU) of bottles that were rinsed with tap water and those cleaned with soap and water based on the Independent Sample T-test. Conclusion: Based on the results, stainless steel water bottles are not required to be cleaned frequently. It also appears that there is no difference between cleaning with soap and water and just rinsing the bottles with tap water. Despite results showing no statistical difference to support more frequent cleaning and more thorough cleaning practices, these behaviours should be encouraged to prevent and minimize the risk of potential exposure to harmful pathogens.