Kerisos 3:1-2

Krisos 3:1

If witnesses told a person that he ate forbidden fats (cheilev), that person must bring a sin offering. If one witness says that he ate it and another says that he didn’t, or if one woman says that he ate it and another says that he didn’t, he brings a conditional guilt offering. If one witness says that he ate it but the person in question denies it, he is exempt. If two witnesses say that he ate it and he denies it, Rabbi Meir says that he is liable. Rabbi Meir explained that if two witnesses are enough to condemn a person to death, they should certainly be sufficient to obligate one in a sin offering! The Sages, however, disagreed because the one who ate the fats could always claim that he did so intentionally. (A sin offering is only brought for unintentional violation.)

Krisos 3:2

If a person ate cheilev more than once in the same state of unawareness, he only needs to bring one sin offering. If he ate cheilev, blood, nosar and piggul in the same state of unawareness, he must bring a separate offering for each. In this matter, multiple things are treated more stringently than a single thing. A single thing is treated more stringently than multiple things in that if a person ate a half-olive volume of a forbidden thing followed by another half-olive volume of the same thing, he is liable; if he ate a half-olive volume each of two different things, he is exempt.