Did you know that Ryvita and Weetabix are Pat Palter too?
The following article by Nathan Jeffay was published in the Jewish Chronicle and gives the background.
For observant Jews, last week’s announcement that leading loaves including Kingsmill and Sunblest have been approved kosher by the Sephardi Kashrut authority may be the best thing since sliced bread. But it will leave many puzzled, because it seems to fly in the face of a rabbinic ban on bread baked by non-Jews, even though the manufacture may meet kosher requirements
Determining what bread is halachically acceptable is both complicated and controversial. The average loaf has something approaching 100 ingredients, several of animal origin. And rabbis have argued for nearly two millennia over whether the old edict permitting only Jewish-baked bread still applies
The Mishnah (Avoda Zara 35b) records this insistence on “Jewish” bread, which the Gemara explains as a step to limit social interaction between Jews and non-Jews in order to prevent intermarriage. A similar restriction was placed on oil, but revoked in the late second or early third century, when it proved too difficult for people to keep. There is also a restriction on wine, which is much stricter, since it operates as an extension of a Torah law and not a straightforward rabbinic decree. The Jerusalem Talmud states that the ban on non-Jewish bread (pat akum) was revoked like the oil ruling. But even here, the position is not clearcut: a second opinion claims that it was revoked only in the case of pat palter, professionally baked bread, but not bread baked in a private home.
The Babylonian Talmud is ambivalent. Rabbi Yochanan stated that the ban had not been revoked. But the Gemara remarks that he may have been reacting to other respected opinions to the contrary. Further episodes give the impression that the authority known simply as Rebbe either fully or partially revoked the ban: though the texts are unclear, it is possible that he allowed pat palter but not privately baked bread.
Elsewhere, Rabbi Yehudah Hanasi came close to revoking it, but decided against because he feared to be known as permissive. Nevertheless, Tosafot, the important composite-commentary found on every page of Talmud, claimed that the ban was in fact lifted: it’s just that the repeal did not make it to the final version of the text. Tosafot notes widespread consumption of bread baked by non-Jews among Jews. Maimonides, however, regarded the ban fully binding, a position broadly adopted by the Shulchan Aruch. But both make some allowance for leniencies, and the Shulchan Aruch, significantly, cites an uncontradicted opinion which permits non-Jewish bread when of superior quality, or different variety to Jewish-baked products. French rabbis, for example, apply this clause to permit baguettes from boulangeries which are better than those from Jewish bakers.
Rabbi Moses Isserles, or the Rama, a major influence on Anglo-Jewish practice, took a lenient line: like some Sephardi authorities, he seems to allow gentile-baked bread even where Jewish-baked bread, of whatever quality, was available. But there is near-universal agreement that Jewish-baked bread should be eaten from Rosh Hashanah to Yom Kippur.
Later authorities hold equally disparate positions. But the rise in the 20th century of factory-baked bread, rather than the small-scale production with which earlier generations were familiar, posed new questions. The leading 20th-centuiy American halachist Rabbi Moshe Feinstein implies that the ban on gentile-baked bread did not refer to industrial baking, but avoids a clear ruling. The contemporary American rabbi, Chaim Jachter, questions whether factory-baked bread can even be said to have been baked by non-Jews, given that machines do most of the work, and they are neither Jewish or non-Jewish. He explored this approach in an article, but did not reach a conclusion
Another factor which could exempt mass-produced bread from the requirement of being Jewish-baked is that it is not oleh a shulchan hamelech, “fit for a king’s table,” or in another reading, “to be served at a king’s banquet.” In some opinions, the requirement for Jewish-baked products applies only when they are top quality.
Rabbi Abraham Levy, spiritual head of the Spanish and Portuguese Jews’ Congregation, which runs the Sephardi kashrut authority, told the JC that the new kashrut deal with Kingsmill is not an attempt to resolve centuries of debate. “We are aware of and respect the different views on this issue,” he said. “We simply want to make kosher facilities available to as large a section of Anglo-Jewry as possible.”