A legitimate OU will only appear on a printed label which is used in a factory that is under supervision. If the OU is displayed on a supermarket brand computer-generated label, you can assume that the product was packed in the supermarket and the OU is unauthorized. We have had a rash of problems with groceries, butcher shops and even seforim stores that have taken the liberty of placing the OU on computer-generated labels of candies, nuts, appetizers, meat and poultry, olive oil and the like. When questioned, the proprietors generally claimed that they purchased OU-certified products in bulk containers and then repackaged the items in their own packaging material. Legitimate labels that are affixed in the factory generally have this information.
Consumers are an important source of information.
If you are not certain about the integrity of the logo, we recommend following the advice of the fire department. When in doubt, make sure to call. Better to be certain than sorry. We will be happy to talk to you. Rabbi Luban is a Senior Rabbinic Coordinator in the Orthodox Union's Kashruth Department .