Store cold back-up dishes in the refrigerator and keep hot dishes in the oven set at 200 °F to 250 °F prior to serving. This way, your late arriving guests can safely enjoy the same appetizing arrangements as the early arrivals. Take Temperatures. Hot foods should be kept at an internal temperature of 140 °F or warmer. 1  Use a food thermometer to check. 2  Be aware that some warmers only hold food at 110 °F to 120 °F, so check the product label to make sure your warmer has the capability to hold foods at 140 °F or warmer.