Coffee Machines Stock Germs, Say Scientists

Coffee machine making an espresso. AFP photo
Coffee machine making an espresso. AFP photo
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Coffee Machines Stock Germs, Say Scientists

Coffee machine making an espresso. AFP photo
Coffee machine making an espresso. AFP photo

Scientists have found that all kinds of pathogens gather in coffee grounds and in used pod machine capsules.

According to the German News Agency (DPA), Fritz Titgemeyer, head of the Food Microbiology Laboratory at the Munster University of Applied Sciences in Germany, said that damp coffee grounds encourage the growth of germs.

If you leave a used coffee pod in the machine for a few days before throwing it out, some mould spores may remain in there and you may be adding them to your next brew.

Titgemeyer noted that a heat-stable poison may have developed, a so-called mycotoxin, and you will not be able to see or taste it.

The water containers and the plastic tubes in coffee machines are also a perfect breeding ground for bacteria if they are not cleaned properly. The expert said that bacteria can settle there in the form of biofilms. All removable components need to be cleaned thoroughly.

Titgemeyer added however disgusting it may be to imagine one's coffee machine full of microorganisms, they do not really pose a health risk.

"The water is heated to 80 degrees Celsius, which kills any germs present in the water tank," he said.

If you use the machine to make cold drinks, however, you may need to worry. Titgemeyer explained that in cold-extracted drinks like iced tea or iced coffee, all germs will remain. The good news is that many coffee machines include a self-cleaning program, but there are also extra things you can do to make sure you keep the germs at bay.



These Canadian Rocks May Be the Oldest on Earth

A close-up view of metagabbroic rocks from the Nuvvuagittuq greenstone belt in Nunavik, Quebec, Canada, that are 4.16 billion years old is seen in this photograph released on June 26, 2025. (Jonathan O'Neil/Handout via Reuters)
A close-up view of metagabbroic rocks from the Nuvvuagittuq greenstone belt in Nunavik, Quebec, Canada, that are 4.16 billion years old is seen in this photograph released on June 26, 2025. (Jonathan O'Neil/Handout via Reuters)
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These Canadian Rocks May Be the Oldest on Earth

A close-up view of metagabbroic rocks from the Nuvvuagittuq greenstone belt in Nunavik, Quebec, Canada, that are 4.16 billion years old is seen in this photograph released on June 26, 2025. (Jonathan O'Neil/Handout via Reuters)
A close-up view of metagabbroic rocks from the Nuvvuagittuq greenstone belt in Nunavik, Quebec, Canada, that are 4.16 billion years old is seen in this photograph released on June 26, 2025. (Jonathan O'Neil/Handout via Reuters)

Scientists have identified what could be the oldest rocks on Earth from a rock formation in Canada.

The Nuvvuagittuq Greenstone Belt has long been known for its ancient rocks — plains of streaked gray stone on the eastern shore of Hudson Bay in Quebec. But researchers disagree on exactly how old they are.

Work from two decades ago suggested the rocks could be 4.3 billion years old, placing them in the earliest period of Earth's history. But other scientists using a different dating method contested the finding, arguing that long-ago contaminants were skewing the rocks' age and that they were actually slightly younger at 3.8 billion years old.

In the new study, researchers sampled a different section of rock from the belt and estimated its age using the previous two dating techniques — measuring how one radioactive element decays into another over time. The result: The rocks were about 4.16 billion years old.

The different methods "gave exactly the same age,” said study author Jonathan O'Neil with the University of Ottawa.

The new research was published Thursday in the journal Science.

Earth formed about 4.5 billion years ago from a collapsing cloud of dust and gas soon after the solar system existed. Primordial rocks often get melted and recycled by Earth's moving tectonic plates, making them extremely rare on the surface today. Scientists have uncovered 4 billion-year-old rocks from another formation in Canada called the Acasta Gneiss Complex, but the Nuvvuagittuq rocks could be even older.

Studying rocks from Earth's earliest history could give a glimpse into how the planet may have looked — how its roiling magma oceans gave way to tectonic plates — and even how life got started.

“To have a sample of what was going on on Earth way back then is really valuable,” said Mark Reagan with the University of Iowa, who studies volcanic rocks and lava and was not involved with the new study.

The rock formation is on tribal Inukjuak lands and the local Inuit community has temporarily restricted scientists from taking samples from the site due to damage from previous visits.

After some geologists visited the site, large chunks of rock were missing and the community noticed pieces for sale online, said Tommy Palliser, who manages the land with the Pituvik Landholding Corp. The Inuit community wants to work with scientists to set up a provincial park that would protect the land while allowing researchers to study it.

“There's a lot of interest for these rocks, which we understand,” said Palliser, a member of the community. “We just don't want any more damage.”