When going to visit Shree Krishna (at a temple), Guru-Acharya or a devotee of God with saintly qualities, one should never eat food given by others as such food destroys ones Punya. Here the word ‘Paraan’ is used to indicate food from others except that which has been begged (Bhiksha). Smruti explains, ‘By eating the food from another person or source during the performance of a penance, Yagna, pilgrimage etc, the fruits of such labour are given away to that person.’
An interesting point is we should never abuse the use of a temple for personal gain. Benefits we receive from a temple should be compensated for accordingly - especially in ‘Jamarvaar Beth’ when in many cases, people may not adequately give for what they receive.