Please do not worry, although the kneader cup does contain BPA, it is in negligible amounts.
All the material in contact with food are FDA compliant and has been tested and certified to meet the requirements for Overall Migration in accordance to FDA 21 CFR Part 177.1580. Hence please be assured that it will not pose any health risk when used.
For more information please visit the website: http://www.bisphenol-a-europe.org