A person I know brings to work left-over masholakh manot for his coworkers. Often the food items have already been opened and partially eaten. Although I am sure that the guy is sincere in bringing the food as masholakh manot, but at the same time I know that an underlying reason is because he does not want to waste food. Assuming his intent was to fulfill the mitzvah, does he actually do so in the above scenario? Just to clarify, the guy will NEVER bring to work masholakh manot that he purchased for his coworkers.
EDIT: Does masholakh manot have to be purchased by the giver, or can the giver pass along food items given to them, a/k/a, "regifting".