THURSDAY, March 21, 2024 (HealthDay News) -- Does your water bottle only get washed once or twice a week -- or even less?

Time to switch things up: Even a day or two without washing can encourage the growth of unhealthy germs in the average water bottle, one expert said. 

And, "yes, you could get sick," warned  Dr. Yuriko Fukuta, an infectious diseases expert at Baylor College of Medicine in Houston.

"If you do not clean your water bottle sufficiently, it can lead to a buildup of germs," Fukuta, a professor of medicine, explained in a university news release. "You may have nausea, stomach upset, headaches. You may have allergy symptoms such as sneezing if mold is present."

She offered tips to keeping your water bottle as sanitary as possible.

First off, choose the right type of bottle. Metal or glass beats plastic, Fukuta said, because plastic can develop tiny cracks that are a haven for germs. 

Choose larger-mouthed bottles, because they're much easier to clean, and bottles with built-in straws work best, with one study showing they contained less bacteria. Slide-top bottles were found to harbor the most germs, Fukuta said.

Lots of microbial visitors can inhabit your water bottle, she added. 

Bacteria in your mouth can get into your bottle if you drink directly from your bottle," Fukuta said. "Food particles from your mouth can transfer to your bottle and create a good environment for mold growth. Bacteria and molds from your hands can also get into your bottle."

She stressed that, "not all of the germs are harmful, but you could get sick at some point if you keep getting exposed to many germs."

Fukuta's advice: Develop regular cleaning as a habit to keep your water bottle safe. Wiping down the bottle's mouthpiece with a paper towel after use is a good first step, since that can curb germ growth.

As for washing, ideally that means cleaning after every use. Bottle washing can be either by hand or in a dishwasher (using the hot water cycle). Washing should always include reusable straws, too. 

If washing the bottle by hand, wash your hands first; separate out all the water bottle parts and then wash with a cleaning solution and water, using a clean brush if possible. Air dry the water bottle, and make sure it stays dry between uses. 

While Fukuta advises against the use of plastic bottles, "even metal bottles need to be cleaned because their antibacterial capacity is not sufficient at all," she said.

And don't re-use those single-use plastic water bottles, "because the shape of bottle is difficult to clean and the chemicals used in the plastic bottles, such as BPA, can leach out into beverages in subsequent uses," Fukuta said.

SOURCE: Baylor College of Medicine, news release, March 19, 2024