Keep raw meat, poultry, fish and vegetables separate. When the store packs your groceries, insist that frozen foods stay together, vegetables go in the same bag, meats with meats, etc. If anything is dripping, have the store put those items in a plastic bag.
Juices are a primary carrier of bacteria.
Make certain your refrigerator is working properly and is set at the appropriate temperature. To ensure proper temperature, purchase a thermometer for both your refrigerator and your freezer. The air temperature of your refrigerator should be 40 degrees Fahrenheit and the freezer 0 degrees. Anything that might drip should be placed in a sealed container or a plastic bag and placed at the bottom of the refrigerator so as not to drip on other foods. Wash your hands and all of the utensils that will be used while preparing your food.