A standard lunch box won't survive summer.

For a two-hour hot-weather commute, you need real insulation: a vacuum-insulated food jar for hot food, or an insulated cooler bag with ice packs for cold food. A regular lunch box just isn’t going to keep anything safe.

Your average lunch box is a nylon bag with thin lining. It’s fine for carrying food, but useless at keeping it at a safe temperature. Food starts getting sketchy between 40°F and 140°F, and once it sits in that zone for two hours—less if the car is hot—bacteria start doing their thing. This isn’t about “will it taste good” anymore. It’s “will it make me sick.”

Hot food: use a vacuum-insulated food jar like a Thermos or Zojirushi, not a plastic container. Preheat the jar with boiling water for a few minutes before filling it, and chili, soup, or noodles will stay above 140°F for two hours plus. Cold food: get a lunch bag with actual insulation and throw in a couple of ice packs. Some bags have built-in gel packs, but a decent insulated bag plus a freezer pack works fine. That thin convenience-store lunch bag won’t cut it once your car has been baking in the sun.

You don’t need to spend a fortune. The vessel does the heavy lifting, and any reputable vacuum jar or soft cooler with ice packs will do. Just start with food at the right temperature and don’t expect the bag to fix things.

If your food starts out lukewarm, no lunch box on earth is going to save you.