Stanley The Legendary Classic Lunch Box

When I was a boy of ten, I bought my father a Stanley coffee thermos for Xmas. He was always breaking his coffee thermos as he was a farmer, banging them around. none of them lasted long. So that is why I bought him a Stanley. A couple of years later, it fell off the tractor and he ran over it. It did manage to put a bit of a dent in the side of it, kinda gave the thing a somewhat rugged appearance. I am now 60 years old,Dad is long gone, but I just finished drinking a cup o joe out of that old beat up thermos. Still keeps the coffee hot.

I've had this lunch box for almost a year. I'd like to think I take pretty good care of it but It's developed some rust in places where the paint has chipped off. Nothing a new paint job won't fix. What kind of paint should I use? I was thinking spray paint but what would be safe for food? I really like this lunch box, I use it for work and get lots of compliments.