Be sure to prep before you shop. Next time you go to the grocery store throw a cooler with ice packs into the car. That way, if you have errands to run or it's hot outside you'll be able to keep perishable foods cool. If you forget the cooler ask the butcher or fishmonger for some ice in a plastic bag. Also, put sanitizing wipes that contain alcohol in your purse.
Once at the store clean your cart. Wipe the handles with your wipes. It will help prevent transferring those bugs from your hands to the food you're buying. Don't forget to wipe your hands again on the way out.
Shop in the middle of the grocery store first. This is generally where you'll find drinks and packaged goods which can sit in your cart for a while and be fine. Then head to the produce and bulk food aisles next.
Save things that need to be refrigerated for last. Keep frozen foods together. Separate meat, poultry, and other items in your cart to avoid cross contamination. Give cleaning supplies their own area and make sure items kept apart are bagged separately.
Once you're home put items away as soon as possible. Put perishables in the fridge or freezer. They can begin to spoil in as little as an hour.
Put items in the right place. Milk should go in the back where it's coldest. Keep old containers no more than a week after the sell-by date. Keep eggs in their carton in the back of the fridge too and not on the door.
Don't overstuff your fridge and freezer. Allowing room for air to circulate ensures things stay cold enough. Also, don't stack meats on top of each other in the freezer.
Use the "first in, first out" rule. Store new items in your pantry in the back. Use the oldest unexpired products in the front first.