Black grout inbetween my tile discolored by cleaner?

I used an environmentally friendly cleaner(like 401) on my granite countertop and now my grout seems discolored. I read the bottle and it doesn't say that it contains any products like bleach nor does it have any warnings about discoloration. Are there any home rememdies I can do that will make the grout black again? I have already tried soap and water to no avail.