Final answer:
A nurse should wait 15-30 minutes to take an oral temperature following the consumption of hot food or cold beverages to ensure an accurate temperature reading.
Step-by-step explanation:
The nurse must wait 15-30 minutes to take an oral temperature when the client has recently ingested hot food or consumed cold beverages. Hot foods and cold beverages can alter the mouth's temperature and lead to an inaccurate temperature reading. Vigorous exercise and taking a hot shower can also affect body temperature, but the direct impact on the oral cavity temperature is less compared to the consumption of foods and beverages at extreme temperatures. Exercising vigorously raises your overall body temperature, and you might feel warm, but the mouth temperature may not reflect the core body temperature immediately. In Michael's case, the fever caused by an infection from undercooked food wouldn't have been accurately assessed if his oral temperature was taken immediately after eating or drinking something that significantly deviates from his actual body temperature.