Related על מעשרות 2:5

One who says to his fried, "Take this issur and buy me five figs with it" -- he may eat them one by one and be exempt, but if he combines them together [to eat them], he is liable (Maasr. 2:5). If the homeowner took out food and gave it to him, there is no need to tithe, the words of Rabbi Meir. Rabbi Yehuda says, either way, if he eats [the food] one by one he is exempt, but if he combines it, he is liable.