Eating of the food offered to an idol makes the person a partaker of their deity. Kozhukattai is their god in food form.

Many religions also have long-drawn traditions of eating the food presented to idols which they believe is equivalent to partaking of their deity to whom they offer the food. Kozhukattai (Modhak in Hindi), Sundal and Maavu Urundai are some Thamizh delicacies presented to idols. That is the reason why believers of the Lord Jesus Christ are instructed to abstain from food offered to idols as this would mean partaking of the very idol behind which there is a demon / evil spirit. Are not they which eat of the sacrifices partakers of the altar? What say I then? that the idol is anything, or that which is offered in sacrifice to idols is anything? But I say, that the things which the Gentiles sacrifice, they sacrifice to devils, and not to God: and I would not that ye should have fellowship with devils. Ye cannot drink the cup of the Lord, and the cup of devils: ye cannot be partakers of the Lord's table, and of the table of devils. – 1 Cor 10:18-21.