Coffee machines can harbor dangerous bacteria when they are not cleaned regularly. One of the most concerning is Pseudomonas aeruginosa, a microbe common in water and aquatic environments. In warm, humid conditions like those found in a coffee maker’s reservoir, this bacterium can persist for long periods and form protective biofilms. Health effects range from mild stomach upset to serious infections and septic shock, especially for people with weakened immune systems. If water tanks are not disinfected properly, the bacteria may accumulate and create a lasting film that protects them from standard rinses.
Homemade peelings or cosmetics using coffee grounds left from the machine can pose risks. While using natural ingredients may seem safe, improper storage and lack of sterilization can turn such mixtures into breeding grounds for Pseudomonas aeruginosa and other bacteria. This can lead to skin infections or irritations.
Experts recommend thorough cleaning and disinfection of coffee machines with products designed for this purpose to prevent biofilms from forming inside the water tank. A common approach is to run a cleaning cycle according to the product’s instructions, rinse the reservoir, and allow the machine to dry completely before reuse.
Some guidance also suggests making a scrub from fresh coffee grounds that have not passed through the machine and using it immediately afterward, but care should be taken to maintain hygiene. If a home project uses such ingredients, it is essential to handle them with clean utensils, store them properly, and dispose of any sign of spoilage.
Additional precautions include using water filters, avoiding leaving water in the reservoir overnight, regular descaling, and sanitizing removable parts with approved sanitizers. When handling coffee grounds for any purpose, store them in clean containers and ensure they are dried before reuse.
In Canada and the United States households and cafés are advised to follow manufacturer cleaning recommendations and use products approved for beverage equipment. Cleanliness not only protects taste but also immune health.