I recently bought cod fish from a grocery store and it had worms inside the meat? How can i report it to a newspaper or radio station to prevent other people buying fish products from that store?
First report it to the store. Give them a fair chance to correct it.
Next, contact your newspapers and news stations (on TV) with the "consumer watch" or "community investigator." If they don't have one, call and ask to speak to someone.
Skip the radio - most radio stations only do a news spread 3 times a day. You'll have a better shot at TV stations and newspapers.