When it comes to which side of aluminum foil is toxic the side that is supposedly toxic is the outer side of the aluminum foil.
However there's no evidence that says that one side of the aluminum foil is any more toxic than the other side and it really does not matter which side of the aluminum foil you do use to cook food with or wrap food with.
When you cook food in the aluminum foil it's supposedly leeches toxic chemicals into the food when you heat it up.
However it would do that no matter which side you cook the food in the aluminum foil.
The aluminum foil really is not all that toxic or toxic to your health at all because if it were toxic and caused harm to your health then the aluminum foil would not be sold.
I would not worry about it as I've cooked foods on both sides of the aluminum foil before and still do and never have gotten sick from it.