Is rewarming food dangerous?

Is rewarming food dangerous, what does uranium look like and how do you find it, does olive oil become toxic when it's heated, how can you treat allergies, why don't aeroplane black boxes float, can laser technology be used for water purification, what causes inner ear infections, what's causing itching from exercise and should we be keeping cows near roads? Like this podcast? Please help us by supporting the Naked Scientists