Q: Can I Leave My Leftovers from Lunch in the Car?

A: Don't Use Your Car as a Refrigerator. I checked by putting a thermometer in my car. I checked the temperature of the car at different points in the afternoon. These are the fun things nutrition professionals get to do because no one else will!

I happened to pick a day when it was 35° on an overcast day. Perfect example. Even I was surprised at the temperatures inside the car.

At noon it was 40° degrees in the car.
At the end of an 8 minute ride, it was 55° in the car.
One hour later I got back in the car and it was 68° inside! The sun must have taken a glimpse while I wasn't looking. Note: at that point it was only 37° outside.
At NO point during this day was the car colder than 40°. So all afternoon on this particular day your food would have been breeding harmful bacteria! Refrigerators are always between 32°and 40°to keep our food safe.

Q: Can't I just cook it extra long on high heat when I reheat it? Won't that kill anything harmful?

A: No, do not do it. Don't even try to rationalize and by saying "I'll reheat it on high heat to kill the bacteria ( that I have allowed to grow the entire afternoon in my car)." What about the bacteria that might be heat resistant? They won't die.

Don't allow food to remain in an atmosphere above 40° any length of time.

Foods, especially leftovers, should not remain outside the refrigerator for any length of time. It's like playing Russian Roulette. It may not happen this time but it might next time.