"Across the web, reports of mold, algae, and other water-based bacterial risks remain rampant. Brita water pitchers are a frequently-cited culprit, along with both classic style and single-cup brewing systems like the Keurig."
On 1 October 2014, an article (later aggregated to several other sources) titled "Why I Kicked My Keurig to the Curb" was published to the alternative health site Underground Health. In it, the author made a case against the use of Keurig coffee makers and their proprietary "K-cup" grounds packets for a number of reasons. Most compelling to many readers was a short segue into the issue of mold, bacteria, and algae growth in Keurig brewers.
The author discussed several of her gripes with the Keurig system, questioning whether the cups were imbued with toxins, whether the coffee in K-cups was fresh, and (oddly) whether the matter of numb and tingly lips was linked with Keurig-brewed coffee. However, of all complaints listed, the one about Keurigs and mold was of the greatest concern to readers."