She has to take a bite first!
She might be biased and say everything is good.
She is the one who made it.
also being the one who made it, she can poison all but one portion of it, which she then takes a bite of to show you its harmless
That's why you say "Yours looks better, can we switch plates?" If she refuses, then it's poisoned, if she agrees then she might've planned for this, wait for her to take a bite out of 'yours' then be like "I changed my mind, I'll take that one after all" if she refuses, it's poisoned, if she agrees to switch again, you're just paranoid D: