Health Dangers of Keurig Coffee Machines-Misleading!
Summary of eRumor:
Rumors that Keurig coffee machines harbor bacteria have been circulating the web for years.
Mold and bacteria grows on and in Keurig coffee machines, but the same is true for every other kitchen appliance.
Rumors about the dangers of Keurig coffee makers can be traced back to a blog post headlined “Why I Kicked My Keurig to the Curb.” It has appeared on alternative health and wellness websites since 2014. The post reports:
When I packed up my kitchen to move 500 miles south, I wanted to make sure that my Keurig was completely empty and dry before it went on the moving truck. IMPOSSIBLE!
Keurig.com states, “Once your Keurig home brewer has been primed, you cannot empty the water from the inside. The internal tank of the brewer cannot be drained.”
The microbiologist in me is disgusted at the thought. Back in the day when I worked in a hospital lab, we emptied all water reservoirs daily or they would grow bacteria and a biofilm could develop. You are familiar with biofilms if you ever cleaned the goo out of a flower vase after the flowers have died. Biofilms are found wherever there is water and a surface to stick to (like your shower curtain).
The author of the post doesn’t make any specific scientific claims about mold or bacteria growth in Keurig coffee makers. Instead, she implies that internal Keurig water reservoirs have to be filled with mold and bacteria because they can’t be emptied.
When an ABC news affiliate from Pennsylvania put that claim to the test, however, the bacteria and mold theory didn’t hold water. The station turned to researchers at the Harrisburg University School of Science and Technology to test three Keurig machines for mold and bacteria. The results showed plenty of bacteria on the outside of the machines (mostly from human touching. Swabs from inside the machines came back clean. Leena Pattarkine, a doctor of microbiology at the university, explained:
“The internal piping you cannot clean. You cannot completely drain it,” Pattarkine said.
We tested water coming out of the machine, it came back clean. But there’s always a chance bacteria or mold could seep out into your cup of joe.
“It doesn’t take too long to realize ‘hey I had that coffee, tasted something off or it was smelly,’ or ‘I had that and I felt sick, nauseated or something,’ ” Pattarkine said.
In other words, mold and bacteria that can get into your coffee would most likely come from the outside of your Keurig. That much is true for other types of coffee makers and kitchen appliances, too. In fact, scientists in Spain reported in December 2015 that potentially harmful bacteria grows in most types of coffee makers, but coffee itself works as an antibacterial agent:
Overall, the bacteria found in coffee waste were similar across all 10 machines, but were highly variable within each community, with up to 67 genera identified in a single machine. The team from the Universitat de València says these bacteria have to be pretty hardy to survive in coffee machines – the coffee itself is an antibacterial agent, and the machines consistently reach temperatures of up to 96°C.
So, it’s true that mold and bacteria can grow on Keurig coffee makers, but health risks and warnings have been overblown. That’s why were classifying this one as “misleading.”