Negative commandment · Lo Ta’aseh #130 of 613
Not to partake of consecrated foods that have contracted ritual impurity
שלא לאכול מן הקודשים שנטמאו
The verse · Vayikra 7:19
וְהַבָּשָׂר אֲשֶׁר־יִגַּע בְּכׇל־טָמֵא לֹא יֵאָכֵל בָּאֵשׁ יִשָּׂרֵף וְהַבָּשָׂר כׇּל־טָהוֹר יֹאכַל בָּשָׂר
“And the flesh that touches any unclean thing shall not be eaten; it shall be burnt with fire: and as for the flesh, all that are clean shall eat of it.”
The Rambam’s words
Not to partake of consecrated foods that have contracted ritual impurity, as [Leviticus 7:19] states: "Meat that has touched any impurity shall not be eaten."
שלא לאכול מן הקודשים שנטמאו, שנאמר "והבשר אשר ייגע בכל טמא, לא ייאכל" (ויקרא ז,יט).
Who & when
“And it is practiced at the time of the [Temple] by males and females.”
Where in the Mishneh Torah
Hilchot Sacrifices Rendered Unfit הלכות פסולי המוקדשין