Nikkur is the process of making an animal kosher by removing chelev (forbidden fats) and the gid hanasheh (sciatic nerve). The basis for this practice is Leviticus 7:23, "You shall not eat of any fatty suet, whether from cattle, sheep, or goats."The English word porge, or porging is from Judeo-Spanish porgar (from Spanish purgar "to purge"); the Yiddish is treibering. The process is done by a menakker.