Rav Vai (author, Bedikas Hamazon) holds that it is considered miut hamatzui, so you need to eliminate the problem by checking 10% to create a chazaka against it.
Klal Yisroel seems to have embraced him wholeheartedly, though it is worth mentioning that my Rav [Harav Y. Stilerman] doesn't consider it a miut hamatzui in the first place (after conversations with Rav Vai, I might add).