…it shall not be eaten. (Leviticus 6:16)
The verse in its entirety reads, “every flour offering of a kohein shall be wholly burned in its entirety; it shall not be eaten.” Normally, three fingers of flour were scooped out of a korban mincha in a process called kemitzah. This amount was burned, while the rest was eaten. Since the korban mincha of a kohein was totally burnt, kemitzah was not performed.
If you refer back to Mitzvah #134, you’ll see that most flour offerings were eaten by the kohanim. This is not the case with flour offerings brought by the kohanim themselves. The reason for the korban mincha is to forge a bond with God. If the kohein were to eat his own offering, it would fail to accomplish that, since it would feel like he just baked bread for his own needs. Even if the kohanim were to eat each others’ flour offerings, it would still feel like they belong to one big “bread club.” Accordingly, God commanded that these loaves be wholly burned and not eaten at all.
This prohibition applied to both men and women in the Temple period. It is discussed by the Talmud in tractate Menachos on pages 46b, 51b, and 73b-74a; it is codified in the Mishneh Torah in the twelfth chapter of Hilchos Hilchos Maaseh HaKarbanos. It is #138 of the 365 negative mitzvos in the Rambam’s Sefer HaMitzvos.