As we learned in the Mishnah (daf, or page 33), ritual slaughter is valid even if no blood flows from the animal at the time of slaughter. With regard to the question of ritual defilement, the Mishnah quotes a difference of opinion:
If a man slaughtered cattle or a wild beast or a bird and no blood came forth, the slaughtering is valid and it may be eaten by him whose hands have not been washed, for it has not been rendered susceptible to uncleanness by blood. Rabbi Simon says, it has been rendered susceptible to uncleanness by the slaughtering.
We learned on yesterday’s daf that the difference of opinion between the Tanna Kamma (=first) and Rabbi Shimon relates to the law that limits ritual defilement of food only to that which has become wet by means of one of seven liquids – wine, blood, oil, milk, dew, honey or water (see Vayikra 11:38) – which “prepares” the item for possible defilement. While ordinarily the blood that flows during slaughter will “prepare” the item for possible defilement, in the case of the Mishnah, where there is no blood, the meat would remain undefiled if touched by someone with unwashed hands. Rabbi Shimon’s position is that the act of slaughter itself raises the status of the animal which “prepares” the animal for possible defilement.
The Gemara on today’s daf discusses Rabbi Shimon’s ruling at some length.
Although the Ran suggests that Rabbi Shimon’s position applies only on a Rabbinic level, other commentaries offer explanations explaining why he believes that the act of shehitah itself suffices to “prepare” the meat to be defiled if touched with unwashed hands. Tosafot Rabbenu Peretz suggests that it is similar to hibbat kodashim – literally “the love of consecrated objects.” When something is set aside as consecrated to the Temple, the importance that that object attains causes it to become sensitive and susceptible to ritual defilement. Similarly, in our case, where the animal that cannot be eaten is slaughtered and becomes kosher food, there is an element of hibbat shehitah stemming from the change of status that causes it to become susceptible to ritual defilement.