Coffee makers by Keurig can develop mold due to the moisture generated by the machine's brewing system and water tank. Aside from mold, Keurig coffee makers can also develop mildew, which affects the taste of the drink being made. The presence of mold and mildew can also cause allergic reactions.
If left uncleaned, mold and mildew in coffee can cause certain health hazards, such as coughing, respiratory infection, bloating and diarrhea. Mold and mildew can also develop in other appliances similar to Keurig coffee machines. A Keurig coffee maker can be cleaned by using a variety of cleaning products, such as diluted bleach and white vinegar.