Final answer:
Cold subs should be prepared shortly before pickup time and kept refrigerated until just before consumption to ensure food safety and freshness.
Step-by-step explanation:
Cold subs should be prepared in advance within a safe time frame to prevent bacteria growth and ensure food safety. According to food safety guidelines, perishable foods like cold subs should be kept refrigerated at a temperature below 4 degrees C (40 degrees F) until served. The general rule is that perishable foods left at a temperature between 4 and 60 degrees C (40 and 140 degrees F) for more than two hours should be discarded.
Therefore, it is recommended to prepare a cold sub shortly before it is intended to be consumed or close to the pickup time. Ideally, it should be prepared and kept refrigerated until just before it is needed. This helps to maintain the quality and freshness of the ingredients, ensuring a safe and enjoyable eating experience.
By following proper food handling and refrigeration guidelines, the cold sub can be safely prepared in advance for pickup, but it is essential to keep it refrigerated to minimize the risk of bacteria growth and foodborne illnesses.