Maintain two separate cutting boards: one for meats and the other for fruits and vegetables. Meat juices can contain bacteria that may contaminate other foods if you cut up meat on the same board where you prepare salads. Meat juices can also be absorbed into wood cutting boards--consider using plastic cutting boards for meats and disinfect them with a tablespoon of bleach in a gallon of water periodically or run them through the dishwasher.
Disinfect countertops and sinks regularly, especially after raw meats have come in contact with them. Be sure to wipe up spills of meat juices in the refrigerator to avoid contamination of other foods as well.