Abstract: A food service tray assembly including a tray, a hot food dish, and an insulated dome. Hot food is served onto the dish, the dome is preheated, the food carrying dish is set on the tray, the preheated dome set over the dish, and the tray system delivered to the intended consumer. A thermochromic member disposed in a heat conductive sleeve is mounted in the lift knob of the dome. Thus, without lifting the dome, the server and/or the consumer can readily determine from the color of the member whether the covered food is still at a safe heating temperature.

Abstract: A rethermalization cart having at each food tray positions therein a pair of electrical heater pads positioned to controllably heat separate food servings on a food tray positioned in the cart. Mounted in each pad is a hollow dowel of thermochromic material and surrounded by a heat conductive sleeve. The color of the material is readily visible from outside of the cart to indicate whether the food associated with that pad is safely heated. A light bulb is connected to the electrical heating circuit of the pad so that when the circuit is "on" the bulb is lit. When lit, the bulb shines through the hollow dowel. The cart, when in position in a refrigerator unit, is plugged into an electrical receptacle in the unit. When the cart is moved in or out of the unit to access the trays, the cart becomes unplugged. Although the light bulb is thereby extinguished, if lit, the thermochromic dowel still indicates by its color the thermal condition of the food.

Abstract: A food service process including a hot food dish and an insulated dome. Hot food is served onto the dish, the dome set over the dish, and the dome covered hot food dish is delivered to the intended consumer. A thermochromic member disposed in a heat conductive sleeve is mounted in the lift knob of the dome. Thus, without lifting the dome, the server and/or the consumer can readily determine from the color of the member whether the covered food is still at a safe heating temperature. In an alternative process, the dome is first preheated and then placed over the plate of hot food. Then similarly, after the plated food is transported to a different location and delivered for consumption, the server and/or the consumer can determine from the color of the thermochromic member whether the food is still at a safe temperature for consumption.