Whether leftovers can be eaten cold for lunch depends on the food type and how it was stored. Some foods are safe and delicious cold, while others pose a health risk if not reheated properly.
Certain foods are generally safe to eat cold as leftovers, provided they were properly cooled and stored in the refrigerator within one to two hours of cooking. These often include cooked pasta, pizza, fried chicken, and some cooked vegetables. However, foods like rice, poultry, and seafood are higher risk and should ideally be reheated to an internal temperature of 165°F (74°C) to kill any bacteria that may have grown, even under refrigeration. The key is to ensure the food was cooled quickly to prevent bacterial growth in the first place. Large quantities of food should be divided into smaller containers to speed up the cooling process. Also, consider the ingredients; foods containing mayonnaise or dairy products are more susceptible to bacterial growth and should be handled with extra care. If you're unsure about the safety of a particular leftover, it's always best to err on the side of caution and reheat it thoroughly or discard it.
Always use a food thermometer to check the internal temperature of reheated leftovers, especially meat and poultry, to ensure they reach a safe temperature of 165°F (74°C). This is the best way to guarantee that any harmful bacteria have been killed.