Some kosher products cost a lot more than their non-kosher counterparts. Kosher chicken, for example, costs more than twice as much as the regular variety. This provides a big incentive for a dishonest stores to misrepresent non-kosher items as kosher, and fraud is a real concern.

To counter this problem, kosher consumers have come to rely on independent kosher-certifying agencies. Food producers can pay these agencies to inspect the ingredients and processing, and to certify that the product is kosher. A variety of symbols are used to indicate which agency has certified a product as kosher.

For example, look at this label from a bottle of Heinz ketchup:

Look just to the right of the pickle, and you'll see a U inside a circle. That'sthe symbol of the Orthodox Union, which certifies that Heinz ketchup is kosher. The Orthodox Union is the largest kosher-certifying agency in the world. According to their website, they certify over 400,000 products! If you look in your cupboard, you'll probably find several products with their symbol.

Other well known symbols include the Star-K, the OK, and the Kof-K.