I spent several months in Japan for work and
took advantage of the educational opportunity
by learning to cook a lot of traditional
Japanese dishes. Soup being the basis of
many cuisines, Nippon being no exception, I
can testify that Kombu makes an excellent
soup stock. I imagine that you may have
better luck using it to make tea if you
simply boil it *first*, then let it steep
to avoid microorganism contamination. I
think that since the stuff is sold mostly
for making soup, it's not intended to be
sterilly packaged.