Kof-K kosher certification comes from Kof-K Kosher Supervision, one of the five largest kosher certification agencies in the United States. It’s a Teaneck, New Jersey nonprofit founded in 1970 by Rabbi Dr. Zecharia (Harvey) Senter. Its mark on a label means a rabbi checked the ingredients and the production line and signed off, the same way an OU, cRc, or Star-K mark works. A hechsher works the same whether it’s stamped on a box of crackers or a bag of frozen fish fillets. You can look up any fish’s kosher status on KosherFish while you’re at it.
Who Runs Kof-K Kosher Certification
Rabbi Dr. Zecharia Senter, who also went by Harvey Senter, founded the agency in 1970 out of North Jersey. He started by supervising a handful of local bakeries. Building the ingredient checklists and inspection contracts fell largely to him from scratch, since that kind of formal documentation wasn’t standard practice yet in kosher supervision. Howard Johnson’s ice cream became one of the company’s first major national accounts. The client list grew from there into a certification body with a presence across the US and abroad. Rabbi Senter died on April 4, 2021.
Two of his sons now run the agency today. Rabbi Daniel Senter serves as Chief Operating Officer and handles day-to-day operations. Rabbi Ari Senter heads halachic policy, the rabbinic judgment calls over what does and doesn’t earn the mark. Rabbi Yehuda Rosenbaum, a brother-in-law, also helps run the agency. A family-run rabbinic staff answering to its own halachic authority rather than a marketing department is standard across the Big Five agencies, not unique to Kof-K.
What Kof-K Kosher Certification Covers
Kof-K’s certification appears on packaged foods, restaurants, and manufacturing facilities across the US and internationally. Alongside the OU, Star-K, OK Kosher, and the cRc, it gets grouped as one of the industry’s “Big Five” agencies. Outlets that cover the kosher food business, like the Forward, use that term. Together those five agencies certify more than 80 percent of the kosher food sold in the US. A rabbinic field representative reviews the ingredient list and inspects the production line before a company earns the mark. The agency rechecks periodically rather than certifying once and moving on. A missed ingredient swap, a shared production line with a non-kosher product, or a new supplier can be enough to trigger a re-review. That’s why the mark on a package reflects an ongoing relationship, not a one-time inspection.
How to Verify a Kof-K Certification on a Product
Kof-K keeps a consumer section on its own site, kof-k.org, where certified companies and products are listed by category. Start there if you’re holding a product with the mark and want to confirm it’s current. Certifications can lapse or change when a company switches supervision or drops a product line. Kof-K’s staff can also confirm a specific product directly if the listing doesn’t settle it. Don’t assume a mark is current forever just because you’ve seen it on the package before.
How Kof-K Compares to the Other Big Five Agencies
Five agencies get grouped together often enough that the industry calls them the “Big Five”: the OU, Star-K, OK Kosher, the cRc, and Kof-K kosher certification. None of these marks outranks another on trustworthiness. Any of them is a reliable signal that a rabbi verified the product. The differences show up in scale, specialty, and which communities recognize the symbol best.
| Agency | Headquarters | Founded | Known For |
|---|---|---|---|
| OU (Orthodox Union) | New York, NY | 1923 (certification began) | By far the largest, close to a million products worldwide |
| Star-K | Baltimore, MD | 1947 | Pioneered Sabbath Mode appliance certification in 1997 |
| OK (OK Kosher) | Brooklyn, NY | 1935 | Over 700,000 products across 1,500+ companies, strong presence in Asia |
| Kof-K | Teaneck, NJ | 1970 | Family-run, food and restaurant certification nationwide |
| cRc (Chicago Rabbinical Council) | Chicago, IL | 1932 | Certification covers 126,000+ products across 1,840 companies |
Kof-K doesn’t compete with the OU on raw volume, and neither does any of the other three. What it’s built instead is a reputation as a nimble, family-run operation that moved early into restaurant certification and ingredient-tracking systems other agencies later adopted.
Does Kof-K Certification Cover Fish?
There’s no species-by-species kosher fish list published under the Kof-K name, the way KosherFish maintains one. For any fish, certified or not, the underlying rule comes from the Torah’s test in Leviticus 11:9-12 and Deuteronomy 14:9-10. A kosher fish needs fins and scales that can be removed without tearing the skin. A whole fresh fish still wearing its skin and scales generally doesn’t need a hechsher, because you can check it yourself at the counter.
That check disappears once a fish is filleted, breaded, smoked, or frozen without the skin, which is exactly where certification matters. Kof-K’s mark shows up on packaged and frozen fish products, including plain frozen fillets sold under retail store brands. A rabbinic coordinator has already confirmed the species and the production line in those cases. That beats leaving it to the shopper to guess from a fillet with no scales left to inspect.
Kosher fish is pareve, neither meat nor dairy, so a Kof-K-certified fish product can sit on a meat or dairy table without breaking that separation. Some communities do keep a custom against eating fish and meat at the very same course, so ask your own rabbi if that applies to your household. Pareve status itself isn’t in question once a fish clears the fins-and-scales test, certified or not.
Check Any Fish with KosherFish
A hechsher on a package tells you a rabbi checked it. It doesn’t answer the more basic question this site is built to answer: does the species itself qualify as kosher in the first place? Search the full kosher fish list for the exact species you’re holding, or use the lookup tool on the homepage to check it in seconds. The iOS app and the Android app put the same lookup in your pocket for the next time you’re standing at a fish counter or reading a menu.
Frequently Asked Questions
What is Kof-K kosher certification?
Kof-K kosher certification comes from Kof-K Kosher Supervision, a Teaneck, New Jersey agency founded in 1970 by Rabbi Dr. Zecharia Senter. It’s one of the “Big Five” US kosher certifiers, and its rabbinic staff inspects ingredients and production facilities before a company earns the mark. Two of the founder’s sons, Rabbi Daniel and Rabbi Ari Senter, now run the agency.
Is Kof-K trustworthy?
Yes. Kof-K kosher certification is widely recognized as one of the Big Five US kosher certifiers, alongside the OU, cRc, Star-K, and OK Kosher. Those five agencies together certify more than 80 percent of the kosher food sold in the US. The mark means a rabbinic field representative reviewed the ingredients and inspected the facility before certification was granted.
What does the Kof-K symbol mean on food?
The Kof-K mark on a package means the agency’s rabbinic staff checked the ingredients and the production facility. That review confirms the product meets kashrut, Jewish dietary law, the same way an OU, cRc, or Star-K mark does. Each agency’s symbol stands in for an inspection you can’t perform yourself, especially once a product is processed.
How do I verify a Kof-K certification?
Check the consumer section at kof-k.org, which lists certified companies and products by category. Don’t rely on the symbol alone if you’re unsure, since certifications can lapse or change when a company switches supervision. Kof-K’s staff can confirm a specific product directly if the online listing doesn’t settle the question for you.
Does Kof-K cover fish products?
There’s no species-by-species fish list, but the certification does cover packaged and frozen fish products, including plain frozen fillets. Guidance follows the Torah’s fins-and-scales rule in Leviticus 11:9-12. A whole fresh fish with its skin intact usually doesn’t need a hechsher, but a filleted or processed fish does, since the scales you’d check by hand are gone.
Is Kof-K the same as the OU?
No, they’re separate, independent agencies, each with its own rabbinic staff and its own mark. Both belong to the Big Five group of widely recognized US kosher certifiers, and both apply the same underlying kashrut law. The OU is the largest of the group by volume. Kof-K is a smaller, family-run agency founded decades later.
The Bottom Line
Kof-K kosher certification is real, family-run, and one of the Big Five in the US. Rabbi Daniel and Rabbi Ari Senter now run the agency their father, Rabbi Dr. Zecharia Senter, founded in 1970. It certifies packaged, restaurant, and manufactured food nationwide, including frozen and processed fish products, though it doesn’t publish a species-by-species fish list the way KosherFish does. Any product carrying its mark has been checked against the same Torah standard every kosher agency applies.
If you’re trying to figure out what a symbol on your food actually means, start with what OU kosher means or the full rundown of kosher symbols explained, or see what Star-K certifies and what cRc certifies for comparison. If your question is about a specific fish rather than the mark on the package, check when fish actually needs a hechsher, search the full kosher fish list, or use the lookup tool to check any species by name.