Gittin 53A

היינו ״מדמע״.

is the same as mixing teruma with non-sacred produce, as both involve intermingling that which is forbidden with that which is permitted, so that the entire mixture becomes forbidden. There is no difference between these actions, so there would be no need to mention both of them in the Mishnah.

ואידך ⁠– קנסא הוא, ומקנסא לא ילפינן.

And the other Sage, Shmuel, holds that one who mixes teruma with another person’s non-sacred produce is liable for a fine. And we do not derive a fine in one case from a fine stated in another case, even if the two cases are similar. Consequently, liability for the fine must be mentioned separately for each case.

ולמאן דיליף קנסא מקנסא ⁠– כל הני למה לי?

The Talmud asks: And according to the one who says that we do derive a fine in one case from a fine in another case, why do I need all these cases mentioned in the Mishnah, i.e., one who renders another person’s food ritually impure, one who mixes teruma with another’s non-sacred produce, and one who pours another person’s wine in a rite of idolatry?

צריכא; דאי תנא מטמא; אי תרומה ⁠– הוה אמינא משום דקא מפסיד לה לגמרי, ואי מטמא חולין ⁠– משום דאסור לגרום טומאה לחולין שבארץ ישראל; אבל מדמע ⁠– אימא לא.

The Talmud answers: All 3 rulings are necessary, as, had the Mishnah taught only the case of one who renders another’s food impure, there are two possibilities: If it is referring to one who renders another’s teruma non-sacred, then I would say that they imposed a penalty because he ruined it entirely, as it can no longer be consumed by anyone, neither a priest nor an ordinary Israelite. And if it is referring to one who renders another’s non-sacred food impure, then I would say the fine is imposed because it is prohibited to cause impurity to non-sacred food in Eretz Yisrael. But in the case of one who mixes teruma with another’s non-sacred produce, since he neither caused a substantial loss, as the mixture can still be sold to a priest, nor spread impurity in Eretz Yisrael, one might say that a fine is not imposed upon him.