re: #310 allegro
It’s that you have to actually find a Japanese mayo that is kosher. Mayo itself isn’t the problem. I’ve found other Japanese staples with kosher variations. It’s trying to find specific stuff like this that becomes an issue.
I even saw a kosher fish sauce (Red Boat) being touted at one point around Passover last year, but never could find any around here despite checking out a bunch of specialty stores.