FDA cold temperatures Food and Drug Administration recommends thermometer appliance thermometer FDA "Refrigerator Thermometers: Cold Facts about Food Safety" fda.gov FDA recommends Refrigerator Thermometers: Cold Facts about Food Safety fda.gov FDA 40 F or lower FDA says FDA FDA According to the FDA Refrigerator Thermometers: Cold Facts about Food Safety fda.gov FDA FDA fda.gov set to 0 F FDA FDA 0 degrees Fahrenheit or lower "Refrigerator Thermometers: Cold Facts about Food Safety" FDA recommends far above food safety guidelines FDA fda.gov refrigerator thermometer FDA recommends FDA calculates two hours FDA FDA thermometer appliance thermometer refrigerator thermometer fda.gov FDA recommends FDA 40 degrees Fahrenheit fda.gov FDA fda.gov FDA FDA fda.gov 40 degrees Fahrenheit by the FDA FDA