There are matzos with circle U (O.U.) and matzos with circle K (O.K.).
We want to keep high standards. Please tell us do these hechsherim have high standards?
Does one of them have Higher standards?
closed as unclear what you're asking by Gemini Man, Double AA♦ Apr 7 '14 at 18:46
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Every Kashrus organization has some differentiation in standards. Every one has stringencies that another doesn't have, and every one has leniencies that another doesn't have.
The distinction between them, besides the standard, is how well they follow through and implement their standards.
In general, the best course for evaluating certifications and their suitability to your standards is to ask your own Rabbi. Certifications will answer questions as they are asked, and a Rabbi will know what to ask that is relevant. Certifications are also often more forthcomming with Rabbis that represent communities, as the certifications are more confident that the Rabbi will know how to correctly interpret what they are being told.
Best is a rabbi who has some experience (perhaps as a Mashgiach at some point in his life) in the relevant industry - so in this case someone who worked in a Matza bakery or factory at some point (are we talking about Machine Matza or hand made Matza? Big difference), but even without that, a good familiarity with the Halachic issues involved in making Matza would go a long way in asking relevant questions.
In the absence of an appropriate option in that area, the CRC Chicago will generally answer such comparative questions, but you have to ask specifically about manufacturer names, not just certifications on product types.
In order to look up kosher symbols, check out Reliable Certifications which gives the list by country.
The two you are asking about are viewed as both reliable and accepted by most people.
The Organized Kashrus Laboratories (O/K) 391 Troy Ave., Brooklyn, NY 11213 Phone: (718) 756-7500; Fax: (718) 756-7503 Rabbinic Administrator: Rabbi Don Yoel Levy
The Union of Orthodox Jewish Congregations (OU) 11 Broadway, New York, NY 10004 Phone; (212) 613-8241; Fax: (212) 564-9058 Rabbinic Administrator: Rabbi Menachem Genack