Complain for selling of poisonous mixing mustard oil

In my village one shopkeeper is mixing palm oil with mustard oil and its all becoz local authorities are also helping him to do so for the sake of money they are getting from that shopkeeper . Many times local authorities raided for just show off . But this poisonous oil is consumed by poor villagers and their little children but now my limit is over but i dont know where i should complain becoz it is completely useless to complain to local authorities . Plz guide me