Sweet payasam becomes alcoholic after storing for 2-3 days - (Dec/20/2014 )

why sweet payasam becomes alcoholic after storing for 2-3 days

Most likely because of fermentation.

I do not know the product, but it seems to be some sort of food/beverage that can form alcohol. It contains sugars so its not far fetched that it will form alcohol anaerobically.

Anything (naturally) sweet can become alcoholic after storage and fermentation, but 2-3 days sounds like too short a duration. Do you mean this? (http://en.wikipedia.org/wiki/Kheer) Looking good!