Is it permitted to eat food cooked at the same time as food for khatma?

People here have a practice to give food to the poor after the death of one's relative in the hope that the dead will be rewarded for it, which is termed _khatma_ food. My house also cooks food every Thursday, and the food is divided: a part is sent for _khatma_, and a part remains for my house to eat. **Question:** Is it allowed to eat from the part of the food that is not for _khatma_ but cooked at the same time? I need an answer according to the Quran and Sunnah.