Parshat Vayishlach is seen by the Ramban as a paradigm for a certain type of relationship between Jews and non-Jews. Hence it is appropriate to explore this week the applicability of the Rabbinic prohibition to consume milk that was milked by a non-Jew and not supervised by a Jew.
Indeed this is a question that is often debated in the Orthodox community whether or not one may drink packaged milk that is not under Rabbinic supervision. We will focus on the view of Rabbi Joseph B. Soloveitchik as heard from one of his leading students, Rabbi Menachem Genack. It is vitally important to note that we will address the issue in accordance with the facts that pertain in this country. In many countries, however, it is forbidden to consume milk according to all authorities. These countries include Spain, Portugal, Poland, and other Eastern Europe countries where milk from non-Kosher animals is commonly available.
It is well known among Rabbi Soloveitchik's students that the Rav drank packaged milk that did not have any special Rabbinic supervision. Rabbi Genack mentioned in a Shiur at Yeshiva University that the Rav told him that there exist three considerations to be lenient. Number one, if there are no non-Kosher animals found in the herd of animals that is being milked- אין בעדרו טמא -many opinions rule leniently. Second, we may rely on the government (USDA) supervision and inspections to insure that the milk we consume is from cows. Number three, technically the rabbinic edict forbidden drinking milk from an animal that was milked by a non-Jew does not apply since today the cows are milked by machines.It is interesting to note that a great Israeli authority, Rabbi Zvi Pesach Frank, permitted drinking powdered milk imported from the United States based on virtually the same considerations (שו"ת הר צבי יורה דעה סימן קג).
Let us explore these issues from the talmudic sources. The Mishna (עבודה זרה לה:) records that the Rabbis forbade consuming milk from a kosher animal that was milked by a non-Jew without (observant) Jewish supervision. The Gemara explains that the reason for this enactment is because of concerns that the non-Jew may have mixed non-kosher milk with the kosher milk. Rishonim and Acharonim, however, debate if this prohibition applies even if the non-Jew has no non-kosher animals in his herd (see מרדכי עבודה זרה סימן תתכ"ו, שו"ת הרדב"ז ס' אלף קמ"ז סמ"ק, ס' רכ"ג). Some authorities are lenient only if, in an entire locale, non-kosher animals are not milked. The later Acharonim are divided regarding how to resolve this issue. Pri Chadash (יורה דעה סימן ק ו:ו) and Chazon Ish (יורה דעה מא:ד) rule leniently, whereas Aruch Hashulchan (יורה דעה קטו:ה), Chochmat Adam סז:א(), and Chatam Sofer (שו"ת חתם סופר יו"ד סימן טז(, rule strictly. The latter note that the custom among European Jews was to rule strictly regarding this question. Even if the strict ruling is adopted, the lenient opinions can be used as a סניף להקל, as an adjunct considerations to a lenient ruling. An example of this approach can be found in Rabbi David Zvi Hoffman's responsum (שו"ת מלמד להועיל ב:לג) where he utilized the lenient opinion as a consideration to permit a sick individual, for health reasons, to drink buttermilk that has not been rabbinically supervised. Rabbi Soloveitchik seems to be similarly utilizing these lenient opinions as a consideration to rule leniently, in light of the rule that milk from non-Kosher animals is not commercially available (an owner of a milk factory told this author that it would be economically counterproductive to introduce non-Kosher milk into the milk that is marketed).
The second consideration is to rely on the government's inspection of milk to ensure that no non-Kosher milk has been introduced into it. This ruling appears to have its basis in עבודה זרה לט:, which states that the Jewish supervisor of the milking, need not constantly watch the milking. Rather, as long as he has easy access to view the milking, the milk is acceptable. This is because the non-Jew milking the cow is afraid (מירתת) to introduce non-kosher milk, lest the Jew see him. It seems clear that as long as the non-Jew is afraid to put non-kosher milk into the kosher milk, one is permitted to consume the milk. Indeed, many of the great authorities of this century believe that responsible government supervision is halachically equivalent to Jewish supervision in the context of the halacha of Chalav Yisrael. Rav Moshe Feinstein (אגרות משה יורה דעה מו-מט) writes "in a case where there is fear (מירתת) of government penalty this Rabbinic prohibition does not apply." Other authorities who accept this position include the Chazon Ish (יו"ד מא:ד) , Rav Zvi Pesach Frank (שו"ת הר צבי יו"ד סימן קג), and Rav Yosef Eliyahu Henkin (תשובות איברא סימן מג).
It is important to note that according to this approach, it is only permitted to consume milk poured from a container from a USDA supervised company (or any other country that strictly supervises milk production). However, it would not be permitted to drink milk that a non-Jew pours from his own container (see the story related by the ערוך השולחן, יו"ד קטו:ו). Incidentally, Rav Moshe Feinstein rules (אגרות משה יו"ד מו) that this Rabbinic edict does not apply to a non-observant Jew. Others, however, disagree (see שבילי דוד יו"ד קטו:א).
Despite this leniency, it is well known that Rav Moshe Feinstein encouraged (both in writing and orally) people to drink milk that has been supervised by Rabbis. The primary reason for this appears to be based on a Gemara in ביצה ה. - "כל דבר שבמנין צריך מנין אחר להתירו" - which basically means that a Rabbinic edict applies even if its reason no longer applies. This point was strongly emphasized by the Chatam Sofer in his aforementioned responsum regarding Chalav Yisrael.
However, Rabbi Soloveitchik's third reason to rule leniently seems to overcome this obstacle. He asserted that the edict applies only if a non-Jew milks the animal but not if a machine milks the cow. Accordingly, the Rabbinic edict does not apply to the milk we currently drink.
It should be noted, though, that a concern of those who rule strictly is that if Chalav Yisrael is not observed then this law will be forgotten by כלל ישראל (see Rabbi Yaakov Breisch שו"ת חלקת יעקב ב:לז). The concern is that we will forget to observe this halacha when its reason is applicable, such as in countries or circumstances where the lenient considerations are not relevant. Accordingly, even those communities who adopt the lenient position are reminded by those communities that accept the strict position, that sometimes milk can be considered not kosher.
It also should be noted that one who is lenient should serve only Rabbinically supervised milk to those who adopt the strict opinion (see רמ"א יו"ד קיט:ז). On the other hand, those who adopt the strict approach should not regard those who rule leniently as not being observant of kashrut laws, since they are following eminent halachic authorities such as Rav Soloveitchik and Rav Feinstein (see aforementioned רמ"א).