Nespresso coffee machines contaminated with bacteria, according to an investigation

The coffee capsules are not only a considerable burden for the environment, in the machines also harmful germs can collect. (Photo: Daniela Stark /

Investigation: Almost 70 different germs detected in capsule coffee machines
Capsule coffee machines are enjoying growing popularity. While it has long been criticized that this form of preparation leads to a huge waste problem, it does not stop many people from brewing their coffee this way. But now scientists have also proven that such capsule machines are real germs.


Gigantic garbage problem
In Germany alone, calculations suggest that around 5,000 tons of aluminum and plastic waste are produced from around three billion coffee capsules every year. The environmental balance of this form of coffee preparation is really not good. Even so, capsule coffee machines are becoming increasingly popular. Above all, the Swiss Nestlé subsidiary Nespresso can hold its own in the market. A study by Stiftung Warentest, among other things, showed that cheap coffee capsules are also usually good, but many consumers tend to rely on the big names. In addition to the damage to the environment, there is now another point of criticism. Scientists have detected up to 67 different germs in several capsule coffee machines. For some people, this could pose a health risk.

The coffee capsules are not only a significant burden on the environment, germs that are harmful to health can also collect in the machines. (Photo: Daniela Stark /

Almost 70 different germs in coffee machines
Although some substances in coffee have an antibacterial and sometimes even germicidal effect, researchers from Spain have now proven that capsule coffee machines can be true germs. In a study, scientists from the Universidad de Valencia found almost 70 different germs in the containers for used capsules and drip trays. For the study, the results of which were published in the journal “Scientific Reports”, the researchers tested ten different machines from the Nespresso capsule system. These machines in use have been in use in offices or homes for at least a year. They were used by three to 20 coffee drinkers, making at least 20 cups of coffee a day.

Regularly clean the collecting trays and drip trays
As the team headed by Cristina Vilanova reports, up to 67 different germs were found in the collecting containers into which the used coffee capsules fall. The drip trays under the coffee spout can also be polluted if they are not cleaned regularly. In a further step, the scientists carried out a test with a new machine that processed five coffee capsules a day. After two months, a germ environment comparable to that in the machines in the first test series had also formed in their collecting container. The bacteria survive despite the germicidal properties of coffee. In order to reduce the germ load, it is therefore urgently necessary to empty and clean collecting containers and drip trays regularly.

Health risks for weakened people
According to the information, the scientists found germs from the group of enterococci and Pseudomonas in all machines. Enterococci are especially for people whose immune system is already weakened and a health risk for small children. You are at risk of urinary tract and gastrointestinal infections, which can be accompanied by symptoms such as diarrhea, nausea and vomiting. The pathogen Pseudomonas aeruginosa has little harm to healthy people. But for certain risk patients, whose immune system is weakened anyway, the germ represents a serious health risk, especially since it is often particularly resistant to antibiotics. In addition to these two germs, the researchers were also able to detect Stenotrophomonas, Sphingobacterium, Acinetobacter and a few other pathogens. As reported by “”, the researchers do not consider the germs found from a health point of view. In the study they write: "The bacterial communities that were first discovered here described are potentially useful for biotechnologically relevant processes, including decaffeination and biological remediation." (Ad)

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