Rice Dream - Barley Enzyme

Question

I noticed on the website of the company that makes Rice Dream, it says that the product "is processed using a barley enzyme. Even though the barley enzyme is discarded after use, the final beverage might contain a minute residual amount (less than .002%) of barley protein." Why does this not present a problem for use on Pesah? Many thanks for your wonderful work in making this site available. Hag Kasher v'Sameah.