Contamination With Saliva
The concept of 'uchchishtam' (in Sanskrit) 'entho' (in Bengal), 'aitha' (in Orissa), 'jutha' (in North India), 'ushta' (in Western India), 'echal' (in Tamil Nadu), 'echil' (in Kerala), 'enjalu' (in Karnataka), or 'engili' (in Andhra Pradesh) is a common belief in India. It can refer to the food item or the utensils or serving dishes, that has come in contact with someone's mouth, or saliva or the plate while eating - something that directly or indirectly came in contact with your saliva. It can also refer to leftover food. It is considered rude and unhygienic to offer someone food contaminated with saliva. It is, however, not uncommon for spouses, or extremely close friends or family, to offer each other such contaminated food and is not considered disrespectful under such circumstances. In certain cases, as in the first lunch by the newly-weds, sharing food from each other's leaves may be thought as an indication of closeness.
Read more about this topic: Etiquette Of Indian Dining