11 May Shavuous Kashrus Questions
Why do we eat dairy on Shavuos?
The Rama on Orach Chaim 494:3 quotes a widespread minhag to eat dairy foods on Shavuos. The Mishnah Berurah (ibid. s.k.12) proffers the famous explanation for this custom: Bnei Yisroel, upon receiving the Torah on Shavuos, were unable to eat meat right after the Torah was given. There was no time to prepare and check shechitah knives, remove blood and cheilev (non- kosher fats) from meat, and kasher utensils needed to cook and prepare hot meat. Thus, it was necessary on that first Shavuos to consume cold dairy foods. We therefore commemorate this event by also partaking of dairy dishes on Shavuos.
The Rama himself offers another rationale for eating dairy food on Shavuos: The Korban Shtei HaLechem is commanded to be brought on Shavuos; we therefore eat both dairy and meat foods on Shavuos, as this will require us to have two different breads (because we cannot eat the same bread with dairy and meat foods); the two breads necessitated by serving dairy and meat dishes, served on the table, which symbolizes the mizbayach commemorate the Korban Sh’tei HaLechem. (MB ibid s.k.14)
There are some other, less-known explanations as to why we eat dairy foods on Shavuos:
• Moshe Rabbeinu was taken out of the Nile on Shavuos and was thereafter brought to be nursed, and he refused to drink milk from non-Jewish women. • The gematria of chalav is 40, corresponding to the forty days that Moshe was on Har Sinai. • One of the names of Har Sinai is Gavnunim, similar to the word gevinah – cheese. • The Chok Yaakov (OC 494:9) quotes the Kol Bo (s. 52) that the minhag is to eat both honey and milk on Shavuos, as the Torah is compared to honey and milk (Shir HaShirim 4:11).
The custom of eating dairy foods on Shavuos, however, remains cryptic and is not mentioned by many halachic sources, and that is why there are so many possible explanations. (Note that the Rama explains the basis for the custom with a partial conjecture, “and it seems to me that the reason is…”, rather than stating a definitive rationale, as this minhag is of unclear background.)
The most common methods whereby people fulfill the custom to eat dairy foods on Shavuos are by having dairy Yom Tov meals or by serving dairy Mezonos foods after making Kiddush on Shavuos morning (and consuming a regular Yom Tov seudah later). This latter method is suggested by the Darchei Teshuva (YD 89, s.k. 19) as the ideal way to fulfill the minhag of eating dairy foods on Shavuos while partaking of a most proper Seudas Yom Tov. Each of these approaches requires a bit of halachic analysis.
Is one allowed to partake in mezonos food after kiddush?
There is a fundamental principle of ain Kiddush ‘ela bim’kom seudah – Kiddush may only be made at the site of the meal  . Regardless of the rationale for the axiom of ain Kiddush ‘ela bim’kom seudah, one who makes Kiddush without a meal (i.e. he does not eat a seudah after Kiddush, or he recites Kiddush in a location other than where he eats the meal) does not fulfill the mitzvah of Kiddush and must make Kiddush again when and where he eats.
The Tur and Shulchan Aruch (ibid. s. 5) quote the Geonim that one can fulfill the mitzvah of Kiddush without actually eating a full meal at the time and place that he makes Kiddush. Rather, posit the Geonim, a person can consume a mere kezayis of bread or even drink an additional revi’is of wine as his Kiddush-time “meal”, so that he fulfills the requirement of Kiddush bim’kom seudah. The Magen Avraham (ibid. s.k. 11) and Aruch HaShulchan (ibid. s. 8) explain that, according to the Geonim, one can eat what we refer to as Mezonos foods after Kiddush and satisfy the rule of ain Kiddush ‘ela bim’kom seudah. This interpretation of the Geonim’s opinion has become widely accepted, and many poskim permit partaking of Mezonos foods after Kiddush but advise against satisfying the mitzvah by merely drinking an additional revi’is of wine. (See MB ibid. s.k. 25.)
The overall position of the Geonim is one of dispute, as the simple interpretation of ain Kiddush’ela bim’kom seudah is that one must actually have his seudah – a full meal with bread – upon making Kiddush, and some therefore advise that one is best not relying on the Geonim’s approach  . However, the more prevalent practice is to rely on the Geonim’s view and make Kiddush followed by cake or other Mezonos foods.  If one follows common custom (the opinion of the Geonim), it would seem that he can satisfy the minhag of consuming dairy food on Shavuos by eating cheesecake after Kiddush on Shavuos morning. However, it is not so simple.
The approach of the Geonim only postulates that Mezonos food eaten after Kiddush satisfies the requirement of Kiddush bim’kom seudah when the amount of Mezonos food is at least a kezayis. (See MB 273: 21) The problem is that many types of cheesecake have very little flour, and one does not typically consume a kezayis of the dough or flour part of a slice of such cheesecake in the requisite period of k’dei achilas p’ras, “the time it takes to eat a piece of bread” (which, according to Rav Moshe Feinstein zt”l, would be under 3 minutes – Igros Moshe 4:41). Thus, cheesecake with minimal dough/flour content would not seem to qualify as the Mezonos food to eat after Kiddush.
Additionally, even though the b’racha rishona for cake and pie is Mezonos, even when the majority of the cake or pie consists of filling or fruit rather than flour, there is an exception when the flour or dough part of these desserts serves merely to hold the filling or fruit in place and is not intended to provide flavor (OC 208:2). Some cheesecakes are virtually all cheese, and they have a paper-thin layer of tasteless dough which merely keeps the cheese in place. This situation would warrant reciting a Shehakol and would likely not enable one to consume the cheesecake directly after Kiddush. (See OC 208:9 and MB ibid. s.k.45.)
Should one wish to have cheesecake after morning Kiddush,the solution would be to either purchase a cheesecake that has sufficient dough/flour (a kezayis worth that will be consumed within the shiur of k’dei achilas p’ras), or to also eat a kezayis of another type of Mezonos food (e.g. cookies, pastry or cake), making sure to have a kezayis of the Mezonos food in a period of k’dei achilas p’ras, as above. In case one wishes to consume a Shehakol cheesecake, he should first eat a kezayis of Mezonos item right after Kiddush prior to eating the Shehakol cheesecake.