Is My Styrofoam or Plastic Cup Kosher?
Shailah of the Week by Rabbi Zvi Nussbaum
Rabbinic Coordinator, Kosher Hotline Administrator for the Orthodox Union
We all drink from Styrofoam or plastic cups. Could it be that there is a shailah? Could it be that the hot liquid we pour into a Styrofoam cup is an issue?
Believe it or not, these are valid questions. Styrofoam cups are produced using lubricants which may derive from non-kosher sources.
However, Rav Yisroel Belsky, zt”l (Shulchan HaLevi 20:14) writes that he investigated this matter and found that there is no concern for two reasons: The lubricants are foul tasting. And even if the lubricant was initially edible, the lubricants become non-edible once they are part of the Styrofoam cup. Non-edible foods (nifsal me'achilas adam) lose their non-kosher status. The lubricants are not on the surface of the cup, but are part of the body of the Styrofoam. Rav Belsky often quoted Rav Yaakov Kamenetsky, zt”l that a non-kosher ingredient is batel berov (nullified in a majority) if it is mixed into inedible ingredients (such as Styrofoam).
Enjoy your coffee or cold beverage!