Will eating leftover Chinese New Year meals cause cancer?
Expert: The nitrite produced by a meal of overnight vegetables is not enough to cause cancer, but you should pay attention to the way it is stored.
To celebrate the New Year lively, the reunion dinner is essential. But there was a big table full, but very few people could finish it in one meal. It’s hard to eat, but it’s a pity when it’s gone. The Spring Festival holiday officially ends today, so the question arises: Will eating leftover food from the Spring Festival cause cancer? Yangzi Evening News/Ziniu News reporter interviewed Wang Xia, a nutritionist at Nanjing Second Hospital.
Yangzi Evening News/Ziniu News reporter Lu Yanlin
Can overnight meals cause cancer?
Wang Xia introduced that overnight meals may contain nitrite, and nitrite may be converted into nitrosamines, a carcinogen, under certain conditions. However, the nitrite content in overnight meals is usually low, and the nitrite content produced by one overnight meal is not enough to cause cancer.
Carcinogens in food mainly come from improper cooking methods, preservation methods and long-term intake of certain harmful substances. If food is contaminated during cooking and preservation, or long-term consumption of food containing carcinogens may increase the risk of cancer.
"The real safety risk of overnight meals is the harm of microbial contamination during food storage." Wang Xia said that after the delicious food is left to cool for a long time, pathogenic microorganisms may quietly breed. Especially those protein-rich aquatic products, meat, eggs and soy products, they are more likely to become a breeding ground for bacteria and microorganisms. These "invaders" may cause food to spoil, causing gastrointestinal discomfort. Moreover, the nutrients in overnight meals will gradually be lost over time, reducing their nutritional value.
How to safely store overnight meals?
Experts remind that many people are accustomed to waiting for the food to cool down at room temperature before putting it in the refrigerator. This is incorrect. If you haven't finished eating, be sure to put it in the refrigerator in time.
The "Dietary Guidelines for Chinese Residents 2022" proposes that 4°C to 60°C is a dangerous temperature range where bacteria can easily grow and reproduce. When the temperature exceeds 60°C, most bacteria cannot survive; storage conditions at 4°C and below can reduce the reproduction rate of most bacteria and are relatively safe. Bacteria can multiply quickly if meals are left at room temperature for long periods of time. At the same time, long-term storage will also expose the food to microorganisms in the air, exacerbating the risk of spoilage.
Therefore, if there are unfinished meals, be sure to reduce flipping, put them in a clean sealed box, cover them, and store them in the refrigerator. This can lower the temperature of the dishes as quickly as possible and create a negative pressure in the sealed box, thereby reducing the risk of food spoilage. It is recommended that vegetables be consumed within 24 hours to avoid nutrient loss and bacterial growth; meat and poultry can be refrigerated for 1-2 days; seafood can be eaten on the same day as much as possible; rice and pasta can be stored in the refrigerator for 1-2 days.
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Important points: Pay attention to reheating before eating
Experts remind that if there are unfinished meals, try to finish them within 2 days. Before eating, check the food for signs of odor, discoloration or mold. When heating, it is necessary to heat evenly and thoroughly, and stir the food in time to ensure that every part is fully heated. The internal temperature of food must reach above 70°C to kill possible bacteria and microorganisms. At the same time, eat as much heat as you need and don’t reheat it repeatedly.
Animal food: In animal food, although some B vitamins will be lost when reheated, the protein and minerals can be retained, and the taste will not change much. However, aquatic products such as shrimps, crabs and shellfish are usually cooked fresh and tender, and the heating time is short. If the heating is not thorough, all microorganisms cannot be killed. Even if they are refrigerated in the refrigerator, there is a risk of pathogenic microorganisms multiplying. You should try to eat them first. over.
Cold dishes: Cold dishes are more susceptible to microbial contamination and are inconvenient to reheat, so they should be eaten on the same day as much as possible.
Vegetables: If you cook some vegetables, you should try to eat the stem and leaf vegetables first, because after reheating, the color of the vegetables will become darker, the texture will be soft, and the taste will be worse. At the same time, vegetables will lose a lot of nutrients after long storage and repeated heating. For example, the content of vitamin C will decrease due to the extension of storage time, while the sodium content in vegetable soup will increase accordingly. Long-term consumption is harmful to health.
Staple food: If you have leftover rice, you can also add diced carrots, minced meat, eggs, etc. to make fried rice. This will not only make full use of the leftover rice, but also enrich nutrition. If there are leftover pasta such as pancakes, steamed buns, steamed buns, dumplings, etc., put them in a fresh-keeping bag or lunch box. You can refrigerate the ones you will eat the next day, and put the rest in the freezer to steam when you need to eat them.
Wang Xia once again emphasized that once you find that the taste of overnight meals is no longer fresh or even spoiled, you must not eat it again. For people with low immunity, such as infants, young children, the elderly, pregnant women, and patients with chronic diseases and tumors, they need to pay more attention to food safety issues and try to avoid eating overnight meals. "We should develop a good habit of saving food and preparing meals as needed. When cooking, reasonably control the portion of food to meet needs and avoid waste." (Yangzi Evening News)