The mold appears to build up inside the anti-spill tops of not only Tommee Tippee cups, but also other brands. Parents wouldn’t know about it unless they break open the piece.
Tommee Tippee has responded to the viral post, saying they are “actively working” on the issue.
The company also told parents that there is a proper way to clean the cups, including the tops (pdf).
“We learned, as a result of posts, that some people were not satisfied with the result of the sippy valves used in our sippy cups: We apologize for the inconvenience and we assure you that we are actively working on the subject,” they wrote on Facebook.
The company later told Buzzfeed in a statement that they are releasing a new cup and discontinuing the old style.