Chullin 36 - Does the Blood of Shechitah Make Food Susceptible to Impurity?
To become susceptible to ritual impurity, food must come into contact with a liquid. The verse " and drinks the blood of its kill " indicates that blood is considered a "beverage," which can prepare food to become impure, but which kind of blood? Let's analyze the following rule. If one slaughtered an animal and the blood spattered on a nearby gourd, then Rabbi Yehudah the Prince says that the gourd can become impure, but his nephew Rabbi Chiya says that its state is in doubt.
When blood is let from an animal, it drips slowly at first, until, after a few drops, it begins to spurt. The initial spurt is bright, but as the blood continues to flow, it slows and darkens in color. Only this is called the "blood of its kill," when the animal dies. Rabbi Yehudah considers the complete act of slaughter as shechitah , with the "blood of its kill" being part of it, whereas Rabbi Chiya only considers the final moment as shechitah , thus at each stage it is only a doubt if a valid shechitah will result.
Art: Jan Lievens - Jacob Receiving the Blooded Tunic of Joseph