4) The Gemara, Avodah Zarah 38a, notes that the prohibition of bishul akum is due to a rabbinic enactment. Rashi presents two distinct reasons for this prohibition. Rashi in one area writes that the prohibition of bishulakum is based upon the concern that eating food cooked by a non-Jew may lead to close friendship, intimacy and eventually intermarriage, Rashi in another area writes that the chazal prohibited bishul akum out of concern that the non-Jew may add non-kosher ingredients to the food. (Beis Yosef Y.D. 113) The Sefer Divrei Yosef (3:790:4) writes that the accepted view is that of the first view of Rashi and that the prohibition was instituted in order to avoid intermarriage.
5) The Tiferet L’Moshe, cited by the Pischei Teshuva, notes that there is a practical difference between these two reasons regarding a Jewish idol-worshiper and a Jew who publicly desecrates Shabbos. If the concern is one of intermarriage, there is no prohibition of marrying a Jewish idol-worshiper’s daughter. However, if the concern of bishul akum is that one may eat non-kosher, the prohibition equally applies to eating food prepared by someone who does not keep kosher. According to the Divrei Yosef, cited above, who maintains that the accepted reason is that of avoiding intermarriage, one would be permitted to eat food cooked by a non-observant Jew. However, practically the poskim debate whether one may not eat food cooked by a Jew who publicly desecrates Shabbos. For normative halacha, a rav should be consulted.
6)
Bishul Akum includes foods that are cooked, baked, roasted, fried or broiled by a non-Jew. The Rama (Y.D. 113:3) writes that only food cooked using “fire” is prohibited by
bishul akum.
7) In recent years, questions have been raised on the halachic status of microwave cooking. With microwave cooking, energy waves (i.e. microwaves) are generated that cause a molecular movement in the food substance. This movement causes friction between the molecules and in effect causes the food to heat itself. Because no form of “fire” is present in the cooking, there is reason to inquire whether microwave cooking is permitted.
Regarding Shabbos– With regard to hilchos Shabbos, the poskim debate whether cooking with a microwave is a biblical form of cooking or is it merely rabbinic. According to Harav Shlomo Zalman Auerbach zt”l (SS”K 1:127) microwave cooking is not biblically prohibited, while Harav Moshe Feinstein zt”l (Igros Moshe 3:52) rules that since microwave cooking is a common form of cooking, it is biblically forbidden.
Stringent– Harav Noach Isaac Oelbaum shlit”a (Minchas Chein vol. 1 page 177) discusses the use of microwaves with regard to bishul akum and he explains that according to Harav Moshe zt”l food cooked by a non-Jew in a microwave oven is considered bishul akum.16 A strict view was also expressed by Harav Shmuel Wosner zt”l (Shevet Halevi 8:185), Harav Shraga Feivish Schneebalg zt”l (Shraga Hameir 6:52:3) and Harav Yosef Shalom Elyashiv zt”l (Shvus Yitzchak vol. 6 page 61). In the OU Kosher Halacha Yomis series on Feb. 10, 2016 it states: “Although contemporary poskim differ on this question, the OU is not matir bishul akum through microwaves. Rabbi Genack once discussed this shailah with Rav Shlomo Zalman Auerbach, zt”l, who told him that the OU should be machmir regarding cooking with microwaves.”
Lenient– However, there were poskim who permit food cooked by a non-Jew using a microwave. The arguments for leniency are that when one cooks with a microwave he is not cooking by fire and that microwave technology was not available at the time when Chazal created the prohibition of Bishul Akum decree and thus was not included in the prohibition. A permissible view can be found in the Seforim Chelkas Binyamin (page 106), Lehoros Nasan (7:64) and Rivevos Efraim (8:111). Similarly, Harav Moshe Heinemann shlit”a, in an article on the Star-K website, writes, “Bishul akum does not apply to microwaved food. The rabbinical prohibition of bishul akum applies only to conventional cooking methods through fire (e.g., cooking, frying, roasting). Food prepared through microwaving is not included in the prohibition.”
Normativa Halacha– Harav Asher Weiss shlit”a (Minchas Asher Devarim) discusses this question and he concludes that one may rule leniently in case of great need. Likewise, Harav Oelbaum shlit”a discusses this issue at length and he concludes, “The poskim debate whether food cooked in a microwave is subject to the laws of bishul akum. While one should initially (l’chatchila) rule stringently, b’dieved one may be lenient.”
8) The Gemara in Avodah Zarah (38a) presents an important limitation to this rule prohibiting food cooked by a non-Jew, stating that any food which can be eaten raw is not subject to the prohibition of bishul akum, and may therefore be eaten if it is cooked by a non-Jew. It is for this reason that one may drink water that was boiled by non-Jew. (S.A. 113)
9) This applies even to food that tastes better cooked or baked than raw (e.g. baked apples or applesauce). The reason why our Chachomim permitted these dishes is because we can eat this food without the intervention of the aino Yehudi. We do not feel obliged to the cook for his assistance in preparation of these products, thereby lessening any social bond created by the food. (Chochmas Adam 66)
10) The Bach (112) and Shach (152:2) write that a “adam chashuv” (honorable person, such as a rabbi) should avoid eating any food cooked by a non-Jew even if the food is edible raw. Accordingly, rabbis should not drink water boiled by a non-Jew or fruit cooked by a non-Jew. However, the Pri Chadash, Noda Biyehuda and Aruch Hashulchan disagree and maintain that even an honorable person need not avoid eating edible raw food that was cooked by a non Jew.