That being aside the concept of buttle bishishim would definitely apply in this situation and that my friend is likula.
Equipment which was used for Issur becomes forbidden to use for Hetter until it is Kashered. Bittul and Eynoi Ben Yomo don’t help to allow one to use such equipment L’Chatchila without Kashering it. And, most reputable agencies, OU included, do not give Hashgocho on any food where the equipment requires Kashering. [Even though when the consumer buys the food it is already a Bdieved, since the food was already prepared, the actual act of giving a Hechsher is regarded as a L’Chatchila. Hence, no Hechsher can be given.]
For what purpose? The "Issur" was already done, what did that accomplish?
See Remo (YD 81:7) that one must be careful with Kashrus even with regards to someone who is not a Bar Chiyuv (such as a baby), because the food becomes part of him!