NEW YORK (Reuters) - Major League Baseball (MLB) will implement new clubhouse security measures based on the recommendations of last month's Mitchell Report into the use of performance-enhancing drugs in the sport, officials said on Monday.

Among new initiatives, clubs will no longer receive overnight notice before the arrival of drug-testing officials, Commissioner Bud Selig announced in a statement.

New measures will require background checks of all clubhouse personnel, who will also be subject to random drug tests.

The report conducted by former U.S. Senator George Mitchell relied heavily on testimony from a former New York Mets clubhouse attendant and a former trainer who said they had supplied players with banned substances.

It found that doping had been pervasive in MLB before the implementation of testing in recent years.

Clubs will also have to maintain a log of all packages sent to clubhouses at major league parks, and post MLB's policy about possession and distribution of prohibited substances in both home and visiting clubhouses.

Drug-test collectors will have permanent credentials and a permanent area in each ballpark in which to collect samples.

"These security and logistical changes are important additional steps in combating the illegal use of performance-enhancing substances," said Selig, who added that MLB would soon be announcing additional changes based on Mitchell's recommendations.

(Writing by Larry Fine, Editing by Clare Fallon)