A Meat-and-Milk Science Experiment

Q. May one conduct a scientific test on a piece of milk chocolate to see if it contains animal fat, even if this will necessitate heating the chocolate?

A. The Tchebiner Rav (Dovev Meisharim, siman 30) was asked whether a Jewish chemist may test a piece of chocolate to determine if it was adulterated with animal fat. He considers a possible basis to be lenient, first because it is uncertain if the chocolate contains animal fat. Secondly, the Kesef Mishneh (Hil. Tumas Meis 1:2) suggests that the Torah forbade cooking meat and milk as a safeguard against eating meat and milk. Since, in this instance, the chocolate is being heated to prevent others from eating non-kosher, the cooking may not be forbidden. However, in the final analysis, the Tchebiner Rav questions this approach and is not comfortable relying on this leniency. Yabia Omer (YD 7:5) also discusses this question and is lenient for several reasons. One consideration is that some poskim maintain that there is no prohibition to cook basar b’chalav that was already cooked because “ain bishul achar bishul”, reheating cooked food is not considered cooking. (This was discussed in a previous Halacha Yomis.) Since the chocolate was previously cooked, it may be permissible to reheat it even if it contains milk and meat.


The Gerald & Karin Feldhamer OU Kosher Halacha Yomis is dedicated to the memory of Rav Yisroel Belsky, zt"l, who served as halachic consultant for OU Kosher for more than 28 years; many of the responses in Halacha Yomis are based on the rulings of Rabbi Belsky. Subscribe to the Halacha Yomis daily email here.