Amorce Lima Study-What’s growing in the water in those reusable plastic bottles?

Posted on November 19, 2014 by


I came to the Greater Tampa Bay Football Club soccer field and recruited members of my daughter’s soccer team to put reusable water bottles to the test.

Two weeks and many petri dishes later, here’s some news you can use.

If you’ve ever played soccer, you know it’s fast, furious and fun especially when you’re young.

How do children typically take care of their water bottles?

Alivia Carapazza says, “I take my water bottle, and I pour the water out and I scrub it.”

But Grace Kis says, “I just put my water bottle on the counter.  I don’t even pour the water out.”

I recruited 10 players from my daughter’s U13 competitive team and one USF researcher, Amorce Lima, PhD, who came up with an experiment for us.

We gave all 10 girls brand new reusable sports bottles and bottled water so the water source remained the same, breaking them into groups of five – five who wash their bottles after practice every night and five who don’t.

Dr. Lima told the girls to, “Make sure you treat your water bottles as you would normally treat your water bottles.”

In other words, don’t be afraid to just throw them on the ground.

For three nights we met at the soccer fields in Land O’ Lakes, where Lima would take samples of the water from each girl’s bottle.

Lima brought the samples here to a lab in the Morsani College of Medicine at USF, plated them and spent two weeks growing the bacteria and analyzing the data.

Our goal, to see if more bacteria grew in the unwashed bottles.

Lima ruled out bacteria in the water or in the bottle itself.

Then he delivered his results to the girls at the GTBFC fields.  Jackie, my daughter, was in the washed group and little to no bacteria grew.  Gabby was in the unwashed group and her plate was full of bacteria colonies.

Lima said from day zero to day three, 5,000 times more bacteria grew in the “didn’t wash” plates.

Much of the bacteria probably came from the girls, but Dr. Lima says, “There are some E. coli that are pathogenic and salmonella and things that grow in nature. If you introduce that into your water, that can make you sick.”

Lessons learned? Never reuse disposable plastic bottles. Dr. Lima says, “This is a no-no. They have threads around them and bacteria can grow in them as well.”

Stainless steel is OK. Dr. Lima says, “There are fewer places for the bacteria to replicate because they don’t have those threads.”

With reusable plastic, here’s what the girls learned.

“You shouldn’t throw your water bottle on the ground.”

“Do not put it in the dishwasher.”

“Wash it after you’re done.”

“With warm soapy water.”

“Leave it to air dry.”

If you’d like to read about the experiment, click here .

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