Final answer:
Cold food must be thrown out after being held without temperature control for more than 4 hours to prevent bacterial growth and ensure food safety.
Step-by-step explanation:
Cold food held without temperature control must be thrown out within 4 hours. Bacteria and other microorganisms multiply most rapidly at temperatures between 4 and 60 degrees C (40 and 140 degrees F), which is known as the 'danger zone' for microbial growth. According to food safety guidelines, perishable foods that remain within this temperature range for more than two hours may become unsafe to eat due to bacterial growth. However, the USDA permits up to a 4-hour window for consumption or disposal of such foods in controlled environments, such as commercial settings, before they are deemed unsafe. To prevent foodborne illnesses, refrigeration should maintain foods at or below 4 degrees C (40 degrees F), and freezing should be kept below -18 degrees C (0 degrees F).