To check if a packaged product is kosher, look for a hechsher — a trademarked certification symbol from a recognized agency — on the label, then read the status word next to it (Pareve, D for dairy, or Meat). A hechsher means a kosher-supervision agency verified the product's ingredients and production. Globally there are more than 1,100 kosher-certifying agencies and hundreds of distinct symbols (one US directory alone lists 306 across 39 states and 20 countries), but in North America five marks cover most major brands. The catch: a bare letter "K" by itself is not a reliable symbol — more on that below.
The five symbols that cover most products
These five agencies — sometimes called the "Big Five" — are all US-based and recognized worldwide. If you see one of these marks, the product was supervised:
A 'U' inside a circle — the world's largest certifier. OU-D = dairy, OU-Meat = meat, plain OU = pareve.
A 'K' inside a circle — a registered trademark, not the same as a bare letter K.
A 'K' inside a star. Star-D (D inside a star) marks a dairy product.
A 'K' forming the center of a Hebrew 'kaf'.
'cRc' inside a triangle — strong North American recognition.
Why a plain "K" is not enough
A single letter K printed on its own does not guarantee anything. Plain letters of the alphabet cannot be trademarked, so a bare K can legally be placed on a package by anyone — including the manufacturer itself, with no rabbinical oversight. More than 50 different rabbis and organizations in the US use a plain K, and there is no way to tell them apart by sight. By contrast, a K inside a circle (OK Kosher) or inside a star (Star-K) is a registered trademark tied to a named, accountable agency. Rule of thumb: trust a symbol you can name the agency behind; treat a lone K as "unverified."
Pareve, dairy, and meat — read the status word
Kosher law forbids cooking or eating meat and dairy together, so every certified product carries a status that tells you which category it belongs to:
- →Pareve (parve) — neither meat nor dairy; can be eaten with either. Shown by the bare symbol or the word "Pareve."
- →Dairy — marked with a "D" (e.g. OU-D) or "Dairy." This includes products merely made on dairy equipment, even if they contain no milk.
- →Meat — marked "Meat" or "Glatt." Keep it separate from any dairy item in the same meal.
The lesson: the symbol tells you who certified it; the status letter tells you how you can use it. Read both.
Scanning the barcode instead of reading the box
A barcode-scanner app turns the whole lookup into one tap. Instead of hunting for tiny print and trying to recall whether a symbol is real, you point your phone at the barcode (or the hechsher itself) and get a verdict back. This is genuinely useful in a crowded aisle, for symbols you do not recognize, or when a product's status changes between batches. A few caveats kept honest: coverage depends on the app's database, and for a definitive ruling on a specific product — especially for Passover/Pesach — the certifying agency or a rabbi is the final word.
Where Kosher Scanner fits
Kosher Scanner is a free iOS app that does exactly this: point the camera at a barcode or a kosher symbol and it returns a kosher verdict plus an ingredient breakdown showing whether the item is pareve, dairy, or meat. It recognizes the major certifications covered above (OU, OK, Star-K, Kof-K, cRc) and flags non-kosher additives. It is a fast reference and shopping aid — not a substitute for an agency ruling on edge cases — and it's free to try before you rely on it.
Get Kosher Scanner — freeFrequently asked questions
How do I know if a product is kosher?
Look for a hechsher — a trademarked kosher-certification symbol from a recognized agency — printed on the packaging, usually near the product name or ingredient panel. The five most widely trusted in the US are the OU (U in a circle), OK (K in a circle), Star-K (K in a star), Kof-K, and cRc (in a triangle). If the symbol is one of these and there is no conflicting status word, the product was supervised. A barcode-scanner app can do this lookup for you instead of reading the box by eye.
What do the kosher symbols OU, OK, Star-K, Kof-K and cRc mean?
Each is the registered mark of a separate kosher-certification agency, all five headquartered in the US and recognized worldwide. OU is the Orthodox Union, OK is Organized Kashrus Laboratories, Star-K and Kof-K are independent Baltimore- and New Jersey-based agencies, and cRc is the Chicago Rabbinical Council. There are more than 1,100 kosher-certifying agencies globally and hundreds of distinct symbols, but these five — sometimes called the 'Big Five' — cover most major-brand packaged food in North America.
Is a plain 'K' on food a reliable kosher symbol?
No. A single letter K cannot be trademarked, so anyone can print one on a package with no rabbinical supervision behind it. More than 50 different rabbis and organizations use a bare K, and you cannot tell which from the label, so a plain K does not guarantee the product is kosher. A reliable hechsher is a registered trademark from a named agency — a K inside a circle (OK) or a star (Star-K), for example, not a K on its own.
What does pareve (parve) mean, and how is it different from dairy or meat?
Pareve (also spelled parve) means the product contains neither meat nor dairy and can be eaten with either, which matters because kosher law forbids mixing meat and milk. Symbols carry a status letter to flag this: a dairy product is marked 'D' (for example OU-D), a meat product is marked 'Meat' or 'Glatt', and a pareve product carries the bare symbol or the word 'Pareve'. Always read the status word next to the symbol, not just the symbol itself.
Can an app tell me if a product is kosher by scanning the barcode?
Yes. Apps such as Kosher Scanner let you point your phone at a barcode or a hechsher symbol and return a kosher verdict plus an ingredient breakdown (pareve, dairy, or meat). Scanning is faster and more reliable than squinting at small print, especially for symbols you do not recognize. It is a convenience and reference tool — for a definitive ruling on a specific product or holiday (such as Passover), consult the certifying agency or a rabbi.