Do u do parishaychanam(praanaagnihotram) before eating?

i.e.purifying ur food by sprinkling water around &over the food by gayatri mantra and giving offerings to ur pranas(prana ,apana ,vyana,udhana,samana& the brahma). If u dont do this ur food is nothing but equal to excreta and worms. It is a must 4 every brahmin to do this before eating!!!!!