The Chemist’s Kosher: 90 Years of OK Certification

Most kosher symbols began in a rabbinical court or a synagogue office. The OK began somewhere rather less expected: at a food chemist’s bench, among test tubes and titration equipment. Ninety years on, the certifier from Brooklyn says it now covers more than half a million products, made in close to 100 countries.

Who is behind the OK?

OK Kosher Certification was founded in 1935 by Abraham Goldstein, a food chemist, under the name Organized Kashrus Laboratories. The name says a good deal about its approach. Goldstein treated kashrut as something that could be tested as well as supervised, and the organisation still describes itself as having pioneered laboratory analysis of ingredients. Alongside the lab work, it insisted on inspecting plants in person rather than relying on paperwork, and on looking at sub-ingredients as well as the finished product. Both habits remain central to how it presents itself today.

Its headquarters are at 391 Troy Avenue in Brooklyn, New York, and it also has offices in Europe and Israel.

A family story

In 1968 the OK was bought by Rabbi Bernard (Berel) Levy, a Lubavitcher chassid. He travelled in person to inspect factories in Asia and bringing additives such as MSG under kosher supervision. In 1987 his son, Rabbi Don Yoel Levy, took over and led the organisation until his death in 2020. Today an Executive Rabbinical council oversees its certification.

Two more recent milestones show how the OK has grown. In 2014 it won the rights to the .kosher internet domain, and in 2015 Kehilla Kosher of Los Angeles merged into it.

How big is it today?

According to the OK, writing in September 2025 to mark its 90th anniversary, it certifies over half a million products made in close to 100 countries. That is a long way from a single chemist’s laboratory in 1935.

Other published figures are higher still. Wikipedia, without giving a date, credits the OK with more than 700,000 products from over 1,500 companies, supervised by more than 350 rabbis. We prefer the OK’s own dated figure, but either way the scale is considerable.

With offices in Europe and products made in close to 100 countries, the OK is a mark that British and European shoppers may well find on imported goods, from snacks to store-cupboard ingredients.

What the OK standard means

• Laboratory roots: the OK says it pioneered lab-based analysis of ingredients, an approach that goes back to its founder’s chemistry training.
• On-site inspection: it has long insisted on visiting the plant rather than relying on paperwork alone.
• Sub-ingredients: inspections reach down to the components of each ingredient, not just the finished product.

How to check a product

The OK describes its mark as an encircled symbol, and, like every kosher symbol, it is a trademark that may be used only with the owner’s permission. For questions and updates, the OK publishes Kosher Connect, a monthly digital resource with answers from its hotline and alerts about newly certified products.

If you are unsure about a particular item, the safest course is to check with the OK directly rather than rely on how a label looks.

Three things you might not know

1. Kosher certification at the OK started at a chemist’s bench, with test tubes and titration.
2. The OK holds the .kosher top-level domain, which it won in 2014.
3. Rabbi Berel Levy personally inspected factories in Asia, which helped bring additives such as MSG under kosher supervision.

On The Kosher Shop, every food seller tells us which kashrut authority supervises their products, and we check the certificate before their shop opens. Next in this series: Star-K of Baltimore, the certifier behind the Sabbath mode on modern ovens.

Sources: OK: 90 Years of Kosher Integrity (September 2025); Wikipedia: OK Kosher Certification. Figures are as published by the OK.