I used to use quite a bit of liquid nitrogen as a graduate student. It is dangerous in the sense that you could freeze your fingers off. I've splattered some (very small) droplets on my face and forearms, and it gave a mild stinging sensation but didn't leave a mark. Chemically, it's quite inert and shouldn't react with anything in the human body, giving it zero nutritional value and no toxicity.
I don't know where you would buy it. My lab had a large refrigeration device to extract it from the atmosphere. You would probably have to buy a Dewar flask (a nice Thermos) and get it filled somewhere.
I'm afraid that while the thermometer readout may show temperatures to a tenth of a degree, any infrared thermometer you are likely to buy is going to be--at best--accurate to within 1.5-2% of the value read, so more like +/- 3 degree for a pancake griddle. I know this as I was inspired by this episode to go infrared thermometer shopping, and found the cheaper thermometers were only accurate within 4-6%.
Food Science - Liquid Nitrogen Ice Cream
I used to use quite a bit of liquid nitrogen as a graduate student. It is dangerous in the sense that you could freeze your fingers off. I've splattered some (very small) droplets on my face and forearms, and it gave a mild stinging sensation but didn't leave a mark. Chemically, it's quite inert and shouldn't react with anything in the human body, giving it zero nutritional value and no toxicity. I don't know where you would buy it. My lab had a large refrigeration device to extract it from the atmosphere. You would probably have to buy a Dewar flask (a nice Thermos) and get it filled somewhere.Food Science - Thermometer
I'm afraid that while the thermometer readout may show temperatures to a tenth of a degree, any infrared thermometer you are likely to buy is going to be--at best--accurate to within 1.5-2% of the value read, so more like +/- 3 degree for a pancake griddle. I know this as I was inspired by this episode to go infrared thermometer shopping, and found the cheaper thermometers were only accurate within 4-6%.