"Our Constitution has given us the freedom to consume the food of our choice and any act of intolerance is a violation of the basic rights enshrined in the Constitution," the chief minister said in a statement.
Vijayan said he would ask the Tamil Nadu chief minister to take necessary action against those responsible for the attack on R Sooraj.
Sooraj suffered injuries in one of his eyes, the chief minister said, adding it was unfortunate.
The beef fest was held to protest the Centre's ban on the sale of cattle for slaughter at animal markets.