Packing leftovers from the dinner table is a virtue. However, improper handling can pose food safety risks. So, what's the best way to handle these leftovers?
Packing Tip 1: Packaged food should be completely cooled before being put in the refrigerator.
The interior of the refrigerator should be maintained at around 4°C for the stored food to last longer. When you put hot items in the refrigerator, the internal temperature rises, making it impossible to achieve the proper refrigeration conditions, and the food stored inside can easily spoil. Therefore, food brought home for packing should be allowed to cool completely before being placed in the refrigerator.
Packing Tip 2: Packaged food must be reheated.
Food taken out of the refrigerator must be reheated. This is because the temperature of the refrigerator only slows down the growth of bacteria but does not kill them. If not heated before consumption, it can potentially harm the gastrointestinal tract.
Packing Tip 3: The storage time for leftovers should not be too long.
The storage time for leftovers should ideally not span more than one meal. In other words, leftovers from lunch should be eaten for dinner, preferably within 5 to 6 hours. This is because, under normal circumstances, high temperatures of 100°C can kill certain bacteria, viruses, and parasites within a few minutes. However, if food is stored for too long, bacteria in the food will release toxins, which may not be broken down by heating.
Packing Tip 4: Vegetarian dishes are not suitable for packing.
This is because when vegetables are stored for a long time, bacteria multiply rapidly. Many bacteria produce nitrate reductase, which in turn creates nitrites. Nitrites are themselves toxic, and when they react with amino acids and primary amines in food, they form nitrosamines and nitrosamides, which are carcinogenic, thereby increasing the risk of stomach cancer. Therefore, long-term consumption of leftover vegetables is unhealthy for us. This is the same principle as the higher risk of stomach cancer associated with long-term consumption of preserved foods.
Four Key Words for Reheating Leftovers
For the dishes you've packed, there's also a right way to reheat them before eating. Different dishes require different reheating methods.
1. Reheating Fish: The Key Word is Time.
Bacteria in fish dishes multiply very quickly; for example, E. coli can double in number every 8 minutes in an environment of around 20°C. Eating it without reheating is almost certain to cause stomach discomfort. Therefore, packed fish must be reheated for 4-5 minutes. However, overheating for too long will cause the beneficial nutrients in the fish, such as protein, fish oil, and rich vitamins, to lose their value.
2. Reheating Meat: The Key Word is Vinegar.
When reheating leftover meat dishes, it's best to add some vinegar. This is because meat products contain relatively rich minerals, which are lost with the moisture when heated. By adding vinegar during reheating, these substances combine with acetic acid to form calcium acetate, which not only enhances the nutritional value but also makes it easier for the body to absorb and utilize.
3. Reheating Seafood: The Key Word is Condiments.
When reheating seafood, it's best to add seasonings like wine, scallions, and ginger. This not only enhances the flavor but also has a certain antibacterial effect (seafood is most easily contaminated by Vibrio parahaemolyticus and Salmonella, which can cause food poisoning). Ginger, in particular, has antibacterial and detoxifying properties and can counteract the toxins in fish, shrimp, and crab.
4. Reheating Starchy Foods: The Key Word is 4 Hours.
For starchy foods that you've packed, it's best to finish them within 4 hours. This is because they are easily parasitized by Staphylococcus, and the toxins produced by this type of bacteria are not broken down by high heat, so the problem of spoilage cannot be solved. Therefore, if you haven't finished them within this short time, you should not eat them even if they look fine on the outside.