Test: Overnight vegetable nitrite rises sharply, long-term eating may cause cancer?

China Blue News Client, August 1 (reported by reporters from FM93 Traffic Voice) What should I do if I can’t finish cooking at night? Many people will put them in the refrigerator overnight, and it is inevitable to eat overnight dishes
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On the evening of July 27th and the morning of July 28th, the reporter made 3 sets of control sample stir-fries and a salad respectively, and ordered two control sample stir-fries from the restaurant (the stir-fry samples on the 27th were all stored in the refrigerator), and The stir-fried vegetables samples of the 6 control groups were sent to the Beijing Zhiyunda Food Safety Testing Center for testing
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Experimental steps

Source of samples: 3 sets of control samples for homemade stir-fry, one set for cold salad, two sets of control samples ordered by restaurants
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On the afternoon of July 27 and the morning of July 28, homemade stir-fry: scrambled eggs with spinach, fried vermicelli with shrimp skin and cabbage, fried potato shreds, homemade salad

Order hotel takeaway in the afternoon of July 27th and morning of July 28th: ​​Kung Pao Chicken, Lettuce in Oyster Sauce

Note: All samples on July 27th will be stored in the fresh-keeping box in the refrigerator

Test items: nitrite content of overnight vegetable samples of stir-fried vegetables and cold salads and fresh samples

Limit standard: Because the national standard does not regulate the content of related substances in food in the catering industry, there is no "national standard" for stir-frying
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●Sample Kung Pao Chicken No.
1 and No.
2

Ingredients: chicken, peanuts, green onions

Test result: Comparing the color chart, the color of the overnight vegetable sample and the freshly prepared vegetable sample did not change, and the nitrite content of the two samples was almost zero
.

●No.
3 and No.
4 sample oyster sauce lettuce

Ingredients: Lettuce

Test result: Comparing the color chart, the color of the overnight vegetable sample and the freshly prepared vegetable sample did not change, and the nitrite content of the two samples was almost zero
.

●Sample Salad No.
5 and No.
6

Ingredients: cucumber, corn kernels, starch-free ham

Test result: Comparing the color chart, the color of the overnight vegetable sample and the freshly prepared vegetable sample did not change, and the nitrite content of the two samples was almost zero
.

　　●Scrambled eggs with spinach for No.
7 and No.
8 samples

Ingredients: spinach, eggs

Test result: Comparing the color chart, the color of the overnight vegetable sample and the freshly prepared vegetable sample did not change, and the nitrite content of the two samples was almost zero
.

　　●No.
9 and No.
10 samples of fried vermicelli with shrimp skin and cabbage

Ingredients: dried shrimps, Chinese cabbage, vermicelli

Test result: Comparing the color chart, the color of the overnight vegetable sample and the freshly prepared vegetable sample did not change, and the nitrite content of the two samples was almost zero
.

●No.
11 and No.
12 sample fried potato shreds

Ingredients: potatoes, red and yellow peppers

Test result: Comparing the color chart, the color of the overnight vegetable sample and the freshly prepared vegetable sample did not change, and the nitrite content of the two samples was almost zero
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(Note: odd numbers are new dishes, even numbers are overnight dishes)

Test results

The inspection results showed that the nitrite content of the 6 overnight vegetable samples hardly changed
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Beijing Zhiyunda Technology Co.
, Ltd.
Food Safety Testing Consumer Experience Center tester Yang Yusi told reporters that the nitrite content of overnight vegetables has risen sharply, and it is rumored that long-term eating can cause cancer
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The results of this experiment showed that the nitrite content of the overnight vegetables samples of the 6 control groups and the freshly prepared samples did not change significantly, and the nitrite content of the 6 groups of samples was negligible regardless of whether they were freshly cooked or overnight vegetables.
It is much lower than the minimum limit of nitrite in vegetables in the original national standard, which is 4mg/kg
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Zhang Yuping, technical manager of the CEC Experience Center and postdoctoral researcher in agriculture at China Agricultural University, said that from the test results, the nitrite content of overnight vegetables did not rise significantly.
It can be seen that netizens worry that "the nitrite content of overnight vegetables has risen sharply, and long-term consumption is likely to cause cancer.
"It's a rumor
.

Expert opinion: The overnight vegetables are stored properly and can be eaten with confidence

Zhang Yuping said that the nitrite in overnight vegetables is generally converted from the nitrate in vegetables, and the nitrate in vegetables mostly comes from the nitrogen in the environment, especially nitrogen fertilizer.
Nitrate is reduced to nitrite
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Zhang Yuping said that during the cooking process, the reductase in vegetables has been destroyed, and some bacteria will also have nitroreductase.
Therefore, the nitrite content in leftovers is mainly determined by the degree of bacterial contamination and the storage of leftovers.
Conditions, the contact with bacteria for a long time, if there is no refrigeration, the bacteria will multiply and the nitrite produced will also increase
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Zhang Yuping emphasized that it should be noted that it must be stored in the refrigerator.
The biggest safety hazard of overnight dishes is deterioration
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Zhang Yuping emphasized that, compared to overnight dishes, "the processed meat products such as kimchi, pickles and ham sausages that we often eat have higher nitrite content
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Zhang Yuping reminds everyone that summer is a period of high incidence of food poisoning.
Pickles and pickles are immature and the food is not fresh for a long time
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But in such a hot weather, the food will spoil overnight!