When I was growing up, most kosher products had the symbol O-U. But now there seems to be everything – Texas-K, California-K, Minnesota-K. How do I know what kosher supervision is considered reliable?
The Aish Rabbi Replies:
Be aware that just because a product is labeled with a "K" does not necessarily mean it's kosher. In America, there is no law barring a company from putting any letter they want on a label, whether the product is ice tea or pork rinds.
One rabbi told me that he was supervising a kosher bakery in Florida, and when they wanted to start using a non-kosher ingredient, the rabbi told them, "If you use that ingredient, then I will have to remove the certification." They replied, "That's okay, we'll just continue putting a 'K' on our packaging anyway."
For reliable supervision, O-U, O-K, Star-K, and Chaf-K are some of the most common symbols (called “hechshers”). There are many others, some good and some not-so-good. If you have a specific question, you should check with a rabbi well-versed in Jewish law, or try the web site www.kosherquest.org.