If my neighbor Shmerel keeps kosher and otherwise appears to be observant to the best of my knowledge, then I'd be allowed to eat in his house (assuming I'm invited), eid echad ne'eman b'issurin, his "testimony" is sufficient.

Now what happens if it's not his house, but his foodservice business?

My impression (correct me otherwise?) is that when there were bakers and innkeepers (my impression is that people didn't eat out in restaurants, but would stop at inns when travelling) in the Talmud, their kashrut was self-certified.

Today, it's strongly normative for a bakery, ice cream shop, or the like to have external certification, even if owned and run by a kosher-observant Jew.

How long has that been the practice? Do we know anything else about its history?

I'm specifically not asking about matza factories or kosher slaughter, which have a long tradition of being under the town rabbi's supervision. For instance, Shulchan Aruch (Safed and Cracow, c. 1550) opens the laws of kosher slaughter with "who can perform shechitah"; by the time we reach Chochmat Adam (Vilna, c. 1800), his Chapter One begins: "the knives of a town's kosher slaughterers are the property of the town rabbi and under his control."

  • Do you still say eid echad ne'eman b'issurin when he is effectively testifying about himself, saying that he keeps kosher?
    – Menachem
    Commented Jun 24, 2011 at 17:00
  • 1
    @Menachem, yes. Same as when you're invited to someone's house, you're trusting him.
    – Shalom
    Commented Jun 24, 2011 at 17:10
  • related judaism.stackexchange.com/a/11963/759
    – Double AA
    Commented Apr 11, 2013 at 17:49
  • Related: judaism.stackexchange.com/q/36748
    – msh210
    Commented Mar 27, 2014 at 18:19
  • Too short to be in an answer, but I believe this to be the most obvious one: His temptation to cheat at home is minimal, while his temptation to cheat in business is huge. Maybe we have more Kashrut scandals (even with supervision!) than they did in the days of the Talmud.
    – LN6595
    Commented Nov 24, 2015 at 17:27

4 Answers 4


My impression (correct me otherwise?) is that when there were bakers and innkeepers (my impression is that people didn't eat out in restaurants, but would stop at inns when travelling) in the Talmud, their kashrut was self-certified.

Well, people may not have eaten out much, but they certainly bought food. :)

According to the Mishna (Demai 4: link) one can't rely on the seller himself as to his trustworthiness regarding ma`asrot. However, if you arrive in a city and you don't know anyone, you can ask someone, and trust them to send you to the right person, but you can't trust them about themselves even in that case.

The Tosefta (Demai 5:8: link) indicates that once you know people in the city, or if you've been there 30 days, you can rely only on an expert ("mumche") regarding who is trustworthy. And even if you just arrived and know nobody, you can trust only an expert regarding shvi`it and tohorot.

The Rambam (Ma`aser 12: link) codifies this Tosefta.

I don't know the history of requiring supervision of ingredients of prepared foods, or whether the stringency of t'rumot and ma`asrot applied historically outside of places that those laws were in effect. But there is a very long history of requiring trustworthiness for food.

My guess is that the Mishna and Tosefta didn't refer to certification like we have today, but rather to a local rabbi, mayor, lay leader, or possibly nosy maven who could attest to the trustworthiness of the seller that all the relevant mitzvot were performed.


According to a YUTorah shiur by Rabbi Elie Weissman, one of the enactments of the Vaad Arba Aratzos (Poland, around 1600) was not to buy food or wine from someone -- even if he keeps kosher! -- unless he's certified by the town Av Beit Din.

I'd be fascinated to learn more about this...


In a really good Shiur I heard about The Cairo Genizah from rabbi Becher Here there is a Documentation of a Rabbinic supervision given to a Cheese seller in and around the times of the Rambam


I defer to the others who can answer when kosher certification was required, but I think you might also be interested in hearing what has changed over the last 20 years with regard to requirements for a mashgiach temedi (full-time, on-site supervision). When I first came to my community, the city's only shomer Shabbos butcher did not require a mashgiach temedi because he was trusted. The rabbis would come in from time to time, just as they still do with most (but not all) of the dairy restaurants they supervise. According to national kashrus expert Rabbi Moshe Heisler, the first rabbinical councils to require that all kosher meat purveyors and restaurants have a mashgiach temedi was the Vaad HaRabbonim of the Five Towns and Far Rockaway and the Rabbinical Council of Greater Washington (D.C.). In the case of Washington, this requirement became necessary after it was learned (many years back) that a caterer who was believed to be observant also owned a non-kosher catering business and sometimes borrowed equipment from the kosher business to supplement the non-kosher business. Hence the RCW determined that no one should be trusted with regard to meat. The recent events in Los Angeles, where a kosher distributor was found, through police surveillance, to be repackaging non-kosher meat with reproductions of labels for nationally-distributed kosher products. Given the large differences in price between kosher and non-kosher, it is not surprising that people are tempted.

It must be said that a mashgiach temedi also finds problems with major kosher suppliers that has nothing to do with fraud. My wife was a mashgicha for the RCW at a Chinese restaurant. She was instructed by the vaad to check all whole chickens for bruises and unattached organs, such as livers and hearts. Sure enough, she often found hearts and livers still attached in the occassional whole chicken from Empire. When she later toured the Empire plant, they pointed out the various machinery that was installed to make such discoveries extremely rare, as well as the many inspectors they had in place. But given the huge numbers of chickens slaughtered daily, she could understand how a certain percentage of imperfectly cleaned chickens could get past the inspectors and into the saline bath and packaging. The council still checks chickens carefully.

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