Reusable water bottles are everywhere; on office desks, in gym bags, and in kids’ backpacks. And while it’s inexpensive, environmentally friendly, and incredibly convenient to stop by any tap or fountain for a quick refill, there are a few things to remember about these reusable bottles.
Actually, there are a few things to remember about microorganisms: many of them love warmth, moisture, solid surfaces, and unfortunately whatever you ate for lunch.
This means that your bottle could become a breeding ground for many common microbes.
Dr. Charles Gerba, a hygiene microbiologist from the University of Arizona, notes that some bottles will put you more at risk than others. While most twist-cap bottles typically harbor only harmless bacteria that were already present on you, sport bottles or kids’ bottles with a manual push top can house bacteria picked up from your hands after opening and closing the top.
This can include harmful bacteria – including E. coli, and in rare cases MRSA, warns Dr. Allison McGeer, an infectious disease consultant at Mount Sinai Hospital.
During a recent conference, we ran an informal experiment where we asked visitors to bring us a drinking water sample to be tested for total microbial content using the LuminUltra QGA test kit. Many offered water straight out of their reusable water bottles and we compared these results with city water from a nearby fountain.
It was no surprise that there were drastic differences in the results. Treated drinking water typically falls below 1 pg ATP/mL, and the local fountain water ranged from 0.27 – 0.29 pg ATP/mL. The reusable water bottle samples, however, ranged from 22 to a staggering 5500 pg ATP/mL. That record high was found in one metal bottle with a push-open spout. For perspective, it is generally acknowledged that 1 pg ATP/mL is roughly equivalent to 1,000 bacteria – meaning that the water in this bottle contained the equivalent of 5.5 million bacteria per milliliter!
These microorganisms are harmless the majority of the time, but it serves as a reminder to clean your bottles often with hot water and soap, and be sure to dry them well before putting them back into use.