Keep a bag of bags a few gallon-size zip-seals and shopping sacks to segregate wet, sandy, or sloppy items at day's end.
Stock a Fridge To Go
GHRI's tips for fast, safe cooler loading
Layer with Logic
In general, what's on top should be what you'll eat first. Put perishables on the bottom (especially if meat is raw and juices could leak) so they won't be exposed to hot air when someone grabs a soda. Or, use a separate cooler for drinks.
Take a Chill
Blocks of ice stay frozen longer than cubes. Buy gel packs, or fill quart-size milk cartons with water and freeze for DIY chilling (about one carton per four quarts of cooler capacity). Layer ice on top of food once packed cold travels downward.
Don't Fret Over Food
Use your school-year lunch-box trick: Freeze sandwiches and juice boxes overnight they'll stay cool longer and help keep the rest of the contents cold. After your meal, don't bother repacking any perishable food that's been out more than two hours; it's not safe to eat anyway.
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