What is the ruling on eating sweets mixed with alcohol unknowingly?

If someone eats food believing it to be permissible, then it becomes clear that it contained alcohol or impurities, there is no sin upon him, because he did not do so intentionally. Allah Almighty says: "And there is no blame upon you for that in which you have erred, but [only for] what your hearts intended." And this is among the matters for which one is excused due to ignorance.