It is stated that it does not break the fast to swallow bits of food that were left between teeth an
  • "Food remnants that were left between teeth are not considered something that have been taken from the outside and put in the mouth. A grain of rice, on the other hand, is something that is taken from the outside. If a grain of cooked rice is eaten during a fast, it also necessitates kaffarah (expiation that is done by freeing a slave or by fasting 60 consecutive days or by feeding 60 poor people) even though it is smaller than a chickpea. If a grain of uncooked rice is eaten, it necessitates qada (making up for that fast; observing another fast in lieu of a missed or broken fast). But according to the rule of our religion, if a grain of cooked rice that was left between teeth is swallowed, it does not break the fast. If it is swallowed during the performance of a namaz, it does not nullify the namaz, either. But if a grain of rice is taken from the outside and is swallowed, it nullifies the namaz. This means to say that swallowing bits of food that were left between teeth is different from taking something from the outside and swallowing it.

    It is a disease to examine Islamic rules with our limited intelligence, to compare them with one another, and to try to understand the divine reasons in them. We must strictly avoid such things. If the religion were based on mind and reason, prophets would not have been sent and religious rules would not have been revealed. "