- Question: Why can a drunk or blind
man take challah from dough but cannot take Teruma from fruit?
One is not allowed to take teruma from bad quality fruit for good quality
B. One takes challah from a whole bowl of dough made from five pounds of flour.
Answer: There is no such thing as taking from the bad for the good by challah it is all the same dough so you can be drunk or blind when performing that mitzvah but by teruma you have to be cognizant enough to differentiate so they can’t do it. See Shach Yoreh Deah 328:2:4.
According to Rav Yaakov Emdan why can challah only be nullified if it
accidentally fell into another batch of dough but not if it fell into the dough
it was taken from?
The Torah requires one to take a piece of dough and give it to the kohen
(nowadays we burn it) if an amount of dough of at least 1660-2250 grams of
flour was made.
B. This dough is holy like teruma and can only be nullified 1 in hundred times the amount of dough it falls into and gets mixed up according to the Rema (Yoreh Deah 323:1).
Answer: Pischay Teshuva (2) says that according to him if the dough falls back into where it was taken all the dough becomes untithed again therefore it is not nullified but if fallen into some other dough it doesn’t affect that dough in anyway so it can be nullified.