Bacteria Joining Us For Coffee
The meeting was grueling, the boss is cranky, and it’s just 9:30 a.m.
Only a coffee break could beat these blues - a steaming hazelnut roast that somehow tastes even smoother in that charming but slightly crooked mug the kids made in art class.
Aaahhhhhh.
Liquid relaxation.
Caffeinated escapism.
Bacterial organisms by the bucketful.
What’s that last one?
Yup. University of Arizona researchers turned their scientific eyes to office coffee cups and found the average mug harbors no end of disgusting creepie crawlies.
There are garden variety bacteria. Slightly scarier coliform bacteria that signal poor hygiene. Even the dreaded E. coli.
Common ceramic mugs are bad. Mugs with lids - which create a safe, covered home in which bacteria can happily multiply - are even worse.
And there’s no use getting all smug because you wipe out your mug in the office break room each morning.
To assess the impact of daily cleanings, researchers tested several mugs, wiped them with communal sponges or dishcloths and tested again.
Not only did bacteria levels not fall after cleanings, they soared. And we mean soared.
Pre-wipe, for example, 20 percent of mugs were carrying bacterial organisms - 60 to 400,000 of them, depending on the mug.
Post-wipe, every single mug was infested with between 700,000 and more than 1 million organisms. Even worse, 20 percent of the previously uninfected mugs had picked up E. coli.
Even the researchers were taken aback.
“It was kind of surprising,” said Ralph Meer, a food safety specialist in the UA’s department of nutritional sciences. “The numbers seemed so high.”
On reflection, though, the results make sense, Meer said.
Because people generally drink coffee slowly, throughout the day, there is usually liquid in the mug - or at least a little goopy crud at the bottom.
The moist environment is ideal for bacteria, which reach the cup via the air, the drinker’s lips or a dirty spoon used to stir the brew.
Amplify that effect a hundredfold for a dishcloth or a sponge, which - because of frequent use - sits there damp and increasingly dirty throughout the day.
Throw in the occasional food particles dumped into the sink or transferred to the sponge when someone wipes out a lunch dish, and you have a veritable bacteria bash, Meer said.
At home, most people wouldn’t dream of simply wiping a dirty dish, putting it back in the cupboard and using it again.
At the office, though, such behavior seems to be the norm, said Charles Gerba, a UA microbiologist who conducted the study with Meer.
Gerba himself - a man whose warnings about the invisible grime of flushing toilets and unwashed kitchen sponges have changed the cleaning habits of squeamish people everywhere - was unknowingly harvesting untold colonies of bacteria in his desktop mug.
“I never even thought about it,” he confessed. “My cup was really gross after a couple weeks’ use, and when it got too bad, I just got a new cup.”
These days, Gerba said, he washes his mug daily with soap and hot water, then dries it with a paper towel.
“I’m a little more paranoid,” he said.
That’s the good news about the $2,000 study, commissioned by the New York-based distributor of an electric mug and spoon washer designed for office counter tops.
Killing the bacteria growing in that mug is as easy as giving it a thorough bath with plenty of soap and hot water.