Is Your Coffee Hiding a Deadly Secret?

Your coffee machine could be dispensing more than meets the eye. Here’s what you need to know about the potential for deadly bacteria in your caffeine fix.

When was the last time you deep-cleaned your coffee maker?

If it’s been a while, an array of bacteria could be lurking on or in it.

That’s what the CBS Chicago affiliate discovered after having Loyola University test swabs from the coffee machines of 10 households.

The bacteria, found in eight of the 10 machines — or in water in those machines — included strains like Staphylococcus (commonly called “Staph”), Streptococcus (“Strep”) and Bacillus cereus, which produces toxins. The tests also revealed enteric bacteria, which is found in the intestinal tract. Like E. coli, it is a common cause of food poisoning that has the potential to kill.

“I would probably be concerned about (enteric bacteria),” Loyola University microbiologist Roman Golash tells CBS Chicago.

Parts of the machines that were swabbed and tested include:

  • The cup containing coffee grounds
  • The area where the coffee comes out
  • The water reservoir

A 2011 study by NSF International, an independent nonprofit, cited coffee machine water reservoirs as being among the “germiest” household items:

Kitchen items such as the coffee maker reservoirs, countertops and stove knobs actually had higher germ counts than bathroom items, such as the bathroom door knob and light switch.

Coffee maker reservoirs were ranked No. 5 in the study. (Dish sponges/rags were No. 1.)

Golash tells CBS Chicago that he recommends the following steps to keep bacteria out of coffee makers:

  • Wash your hands before using a coffee machine.
  • Make sure it’s working properly. (The one-cup machines that were tested heat water to around 192 degrees, which can kill some bacteria.)
  • Use filtered water.
  • Change the water after each use.
  • Flush the machine with vinegar regularly.
  • Let all parts dry completely after cleaning them.

The NSF International study also associated high bacteria counts on household items with insufficient cleaning practices. While such items are generally wiped down regularly, they aren’t properly disinfected, and bacteria are frequently introduced to the kitchen from a variety of sources:

Sources of coliform can be traced to many food items, including unwashed produce as well as raw meat and poultry. In addition, coliform can be introduced into a kitchen area through improperly washed hands and through contact with household pets, including pet dishes and toys.

To learn more about keeping E. Coli out of your kitchen, check out “13 Tips to Avoid E. Coli.”

Stacy Johnson

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