Small, low-cost wireless temperature sensors (120) are provided for sensing the temperature of servingware (121). Each temperature sensor preferably includes a substrate (124); at least one sensor element (122) positioned on the substrate; and an adhesive (126) for securing the sensor element to the substrate and for securing the temperature sensor to the servingware so that the sensor element may sense a temperature of the servingware. The temperature sensors may be used in conjunction with a reader/detector (136) operable to generate a magnetic field of magnitude sufficient to cause re-magnetization responses of the temperature sensor element and optional data elements to detect such responses, and to use the detected responses to determine the temperature of the servingware by means of a decoding algorithm. The temperature sensors can be used in closed-loop heating systems capable of controlling the heating of the servingware.