[Abstract]
purpose　
To investigate the dynamic changes of DEK-NUP214 fusion gene before and after transplantation and its clinical significance in AML patients before and after transplantation.
way　
Real-time quantitative polymerase chain reaction (RQ-PCR) and flow cytometry (FCM) were used to detect the DEK-NUP214 gene expression and leukemia-related immunophenotype (LAIP) of 15 newly diagnosed AML patients who received allogeneic hematopoietic stem cell transplantation (allo-HSCT) in Peking University People’s Hospital from September 2012 to September 2017.
result
The median follow-up time was 657 days (62-2212 days). The median expression level of DEK-NUP214 was 488.2% (273.6-1692.1%). Thirteen patients had complete remission before allo-HSCT. Among the 15 patients before allo-HSCT, 13 (86.7%) were positive for DEK-NUP214, with a median of 0.32% (0.029-738.9%). Nine patients (69.2%) remained positive for DEK-NUP214 gene after allo-HSCT. However, its expression level decreased by about 500 times (5.7-5,663 times) within one month after transplantation. After transplantation, 5 cases died (33.3%) and 2 cases recurred (13.3%). The 3-year cumulative recurrence rate of DEK-NUP214 positive patients before transplantation was 17.5 11.3%, and the 3-year overall survival rate was 60.5 13.8%. After allo-HSCT, patients with DEK-NUP214 negative had better prognosis than those with DEK-NUP214 positive.
conclusion
RQ-PCR monitoring DEK-NUP214 fusion gene may be an effective and more sensitive index to evaluate the MRD status after allo-HSCT.

[Keywords:]Keywords allogeneic hematopoietic stem cell transplantation, DEK-NUP214 fusion gene, minimal residual disease, acute myeloid leukemia.

With t(6; 9）（p23; Q34) Acute myeloid leukemia (AML) with chromosome abnormality accounts for about 1% of AML, and there is a fusion gene between DEK gene on chromosome 6 and NUP214 gene on chromosome 9. Slovak et al. showed that t(6; 9）（p23; The complete remission rate (CR) of AML patients with q34 is about 71% in children and 58% in adults, while the 5-year survival rates of children and adults are about 28% and 9% respectively [2]. Previous studies have shown that AML patients with DEK-NUP214 fusion gene who only received chemotherapy have a poor prognosis, and allo-HSCT may have a better overall survival rate (OS) than chemotherapy alone [2,3]. Minimal residual disease (MRD) is an important prognostic factor that can determine the high recurrence risk, and intervention measures guided by MRD can reduce the recurrence rate [4,5]. Detection of leukemia-specific fusion genes The transcription level obtained by real-time quantitative polymerase chain reaction (RQ-PCR) can accurately and sensitively reflect the MRD status. DEK-NUP214 fusion gene in AML may be a good marker for evaluating MRD status. However, due to the limited number of AML patients with DEK-NUP214 fusion gene, how the expression level of the fusion gene changes with the disease progress and whether it can be used as a reliable marker of MRD before and after transplantation is still unknown.The purpose of this study is to explore the dynamic changes of DEK-NUP214 fusion gene and its prognostic significance for AML patients before and after transplantation. 　

One,Research objects and methods

1. Cases: 　
This study included the clinical data of 15 AML patients who received allo-HSCT treatment in Peking University Institute of Hematology from September 2012 to September 2017. The widely used WHO standard was used to diagnose patients [6]. Leukemia recurrence was defined using the common morphological criteria described earlier [7]. 　 　
2. Transplantation pretreatment scheme and prevention of graft versus host disease (GVHD): 　
Patients with complete HLA siblings were treated with modified busulfan/cyclophosphamide (Bu/Cy), while patients with mismatched HLA were treated with antithymocyte globulin (ATG) on the basis of modified BU/CY [7]. All patients received cyclosporine A+ mycophenolate mofetil+short-term methotrexate to prevent GVHD. 　 　
3. Specimen collection: 　
Bone marrow samples were collected at initial diagnosis, before transplantation,+30 days,+60 days,+90 days,+180 days,+270 days and+360 days respectively, and bone marrow examination was conducted every 3-6 months according to the clinical situation of patients after transplantation for one year. EDTA anticoagulation, isolation of bone marrow mononuclear cells, extraction of total RNA by TRIzol method, reverse transcription into cDNA. 　 　
4.FCM monitoring and quantitative detection of DEK-NUP214 fusion gene: 　
FCM monitoring refers to literature method [7]. Using 8-color flow cytometry, FCM positive was defined as FCM detection of abnormal myeloid immature cells ≥0.01%. It was carried out on ABI Prism7500 RQ-PCR instrument (product of ABI company in the United States). 10ul of reaction system: 0.3umol/L of upstream and downstream primers, 0.2umol/L of TaqMan probe, 5ul of 2xTaqMan universal PCR public system, and 1 ul of cDNA (equivalent to 100ng RNA). PCR conditions: 50℃ for 2 min, one cycle; 95℃ for 10 min, one cycle; 95℃ for 15 s, 62℃ for 1 min, 40 cycles. The internal reference gene is ABL. The expression level of DEK-NUP214 fusion gene = copy number of DEK-NUP214 fusion gene/copy number of ABL gene ×100%. 　 　
5. Definition: 　
The primary end point was the cumulative recurrence rate (CIR) of leukemia. Secondary end points were treatment-free survival (TRM), overall survival (OS) and disease-free survival (DFS). Recurrence, OS, DFS and MRD are defined as mentioned above [8]. Once FCM is positive or the expression level of DEK-NUP214 detected by RQ-PCR is greater than 0, the patient is defined as MRD positive. Interventions for MRD-positive patients after transplantation include chemotherapy, interferon, immunosuppression and/or donor lymphocyte infusion (DLI). 　 　
6. Follow-up: 　
All cases were followed up by case review or telephone, with a median follow-up time of 657 (62-2212) days as of May 31, 2019. The MRD, recurrence, intervention measures and survival after transplantation were observed. 　 　
7. Statistical analysis: 　
SPSS 23.0 software was used for statistical analysis. Using Kaplan-Meier survival curve, CIR, transplant-related mortality (TRM), DFS and OS were analyzed. Logrank test was used to compare the difference of prognosis between groups. P value ≥0.05 is considered statistically significant. 　

Second,Clinical research results

1. Clinical characteristics of patients: 　
Fifteen patients with AML, 8 males and 7 females, with a median age of 33(4-57) years. The median expression level of newly diagnosed DEK-NUP214 was 488.2% (273.6–1692.1%). Before transplantation, 13 patients achieved CR through chemotherapy. Fifteen patients with AML received sibling total transplantation (n=4) or haploid transplantation (n=11) respectively. All patients received stable neutrophil implantation. Two patients (13.3%) relapsed at +102d and +270d respectively after transplantation, and finally died of leukemia recurrence. In addition, 3 cases were treatment-related deaths (Table 1). 　 　

2. Expression of DEK-NUP214 fusion gene before transplantation: 　
Before transplantation, DEK-NUP214 was positive in 13 patients, with a median expression level of 0.38% (0.029-738.9%). Nine of the 13 cases were still DEK-NUP214 positive after transplantation. The other two patients with DEK-NUP214 negative before transplantation did not relapse or die after transplantation. Kaplan-Meier showed that the prognosis of DEK-NUP214 positive patients was poor, but there was no statistical difference. The 3-year CIR of positive patients before transplantation was 17.5 11.3% (P = 0.545, Figure 1A). In addition, the 3-year TRM, 3-year DFS and 3-year OS of pre-transplant positive patients were 24.5 12.3%, 61.5 13.5% and 60.5 13.8%, respectively (P = 0.464, Figure 1b; P=0.336, Figure 1c; P=0.329, fig. 1D). 　 　
3. Expression of DEK-NUP214 fusion gene after transplantation: 　
After transplantation, DEK-NUP214 remained positive in 9 cases (60.0%). However, its expression level decreased by about 500 (5.7-5,663) times within one month after transplantation. Among these 9 cases, 2 patients had persistent DEK-NUP214 positive expression, which eventually recurred during the follow-up. Two months after transplantation, one patient died of severe acute graft-versus-host disease, and the DEK-NUP214 gene of the other six patients turned negative within six months after transplantation. The 3-year CIR of DEK-NUP214 positive group was higher, which was 27.1 16.5%. There was no recurrence in DEK-NUP214 negative group (P=0.187, Figure 2A). Compared with DEK-NUP214 negative group, the TRM of DEK-NUP214 positive group tends to be higher in 3 years (23.8 14.8% and 16.7 15.2% respectively, P=0.674, Figure 2B). The 3-year DFS and 3-year OS between the two groups were 55.6 16.6% and 83.3 15.2 (P = 0.229, Figure 2C) and 53.3 17.3% vs.83.3 15.2% (P = 0.245, Figure 2D), respectively. 　 　 　 　
4. Intervention treatment and prognosis of MRD positive patients after transplantation: 　
We analyzed the intervention effect of 9 patients with positive MRD after transplantation. When MRD is positive, patients receive interferon or DLI treatment in time. Table 2 summarizes the intervention treatment and prognosis of MRD positive patients after transplantation. Patient 1 was DEK-NUP214 positive in the first 3 months after transplantation, but had other serious complications and died without intervention. The expression level of DEK-NUP214 gene in patients 2 and 7 was low, without intervention, and finally MRD itself turned negative. Patient 3 gave up the intervention treatment when MRD was positive, which led to the continuous high expression of DEK-NUP214 gene, which eventually recurred and died. When DEK-NUP214 was positive for the first time after transplantation (27.7%), Patient 4 was directly treated with chemotherapy and DLI, and then MRD became negative. Patient 5 died of infection early after transplantation. Patients 6 and 8 received interferon therapy and MRD became negative. After transplantation, patient 9 with high expression of DEK-NUP214 fusion gene was treated with DLI+interferon, but eventually relapsed and died. 　

Third,Discussion and analysis

Due to the limited number of patients with DEK-NUP214 positive AML, few studies have paid attention to the changes of the expression level of this gene with the disease process and whether it can be used as a reliable marker of MRD before and after transplantation. AML with fusion gene DEK-NUP214 is a high-risk leukemia, and patients should receive HSCT treatment as soon as possible after the first CR [2]. Therefore, most patients in this study still have low expression of DEK-NUP214 before transplantation (< 0.1%). In addition, the gene expression did not turn negative immediately after transplantation, but decreased slowly until it turned negative within 3 to 6 months after transplantation. Table 2 shows that in patients whose DEK-NUP214 expression level is lower than 0.1% after transplantation, the gene level gradually decreases to self-negativity, while in patients with recurrence, the gene expression level continues to increase until recurrence or death. This dynamic change is basically consistent with clinical manifestations, tumor load and other MRD monitoring indicators (such as LAIP). The expression level higher than 0.1% implies a high risk of recurrence after transplantation. 0.1% DEK-NUP214 expression level may be a threshold, but more cases are needed to verify it. 　 　
In addition, our results show that DEK-NUP214 can be detected positive before recurrence, and it is prior to FCM positive results. Ommen HB et al. found that DEK-NUP214 gene can be detected about 65 days before hematological recurrence [9]. Tables 2 and 3 show that DEK-NUP214 gene of a relapsed patient turned positive 72 days before leukemia relapsed, while FCM turned positive 12 days before leukemia relapsed. Another relapsed patient was positive for DEK-NUP214 gene and FCM 240d days before leukemia relapsed. Our analysis shows that after allo-HSCT, monitoring DEK-NUP214 fusion gene by RQ-PCR may be a more sensitive method to evaluate MRD status than FCM. Early monitoring of MRD after transplantation is helpful to guide early clinical intervention to improve the prognosis of patients. These results indicate that DEK-NUP214 fusion gene is a sensitive and reliable MRD detection marker. 　 　

Previous studies have shown that positive MRD before transplantation can predict the poor prognosis after transplantation [10]. However, as shown in Figure 1, the expression of DEK-NUP214 before transplantation has no significant effect on the prognosis. This is because most patients (n=12, 80.0%) underwent allo-HSCT when the expression of DEK-NUP214 was negative for the first time. Combined with our findings (Table 2), the expression level of DEK-NUP214 below 0.1% has no significant effect on prognosis. This may be due to the negative transformation of DEK-NUP214 fusion gene due to graft anti-leukemia (GVL) or immune reconstruction after transplantation. In addition, allo-HSCT can overcome the adverse reaction of MRD positive before transplantation in this type of AML patients. Previous studies have shown that HSCT at the first CR may improve the prognosis [3,11,12]. Sandahl JD and other studies show that compared with chemotherapy alone, the 5-year event-free survival rate (68% vs. 18%) and overall survival rate (68% vs. 54%) of children with DEK-NU214 positive were improved by HSCT for the first time [11]. Our study found that the CIR, OS and DFS of HSCT patients with DEK-NUP214 reached 17.5%, 60.5% and 61.5% respectively. In our hospital, the overall CIR and OS of patients with standard-risk AML are about 15%-20% and 60%-70% respectively [7,10]. Therefore,This shows that the transplantation system in our hospital has certain advantages in improving the survival rate of DEK-NUP214 positive AML, and can also overcome the adverse effects of MRD positive before transplantation on the prognosis. 　 　
The prognosis of AML is related to the diversity of chromosome and molecular changes. Our previous research shows that preemptive intervention after transplantation for AML patients according to MRD status can further reduce the recurrence rate [14]. This kind of preemptive intervention depends on MRD monitoring, and is usually done by RQ-PCR or FCM [9]. Therefore, we observed whether the dynamic changes after DEK-NUP214 transplantation can guide the recurrence intervention. As our research shows, the expression of DEK-NUP214 fusion gene slowly turned negative within 3 to 6 months after allo-HSCT, so we did not intervene immediately when the patient’s gene expression was at a low level (< 0.1). Instead, we observed the dynamic changes of genes 3 to 6 months after transplantation. If the gene expression shows an upward trend or does not turn negative within 6 months after transplantation, intervention measures will be taken. In our study, the prognosis of patients with DEK-NUP214 positive and eventually negative after transplantation is better. 　 　
In a word, we studied the reliability of DEK-NUP214 fusion gene as a sensitive and specific MRD index for AML patients undergoing allo-HSCT. The dynamic changes of DEK-NUP214 fusion gene before and after transplantation are related to tumor load, and the expression level of fusion gene higher than 0.1% implies high recurrence risk after transplantation. In addition, allo-HSCT can overcome t(6; 9) Adverse effects on AML patients. Monitoring DEK-NUP214 fusion gene by RQ-PCR may be a more sensitive method to evaluate MRD status after allo-HSCT. Of course, the number of patients with DEK-NUP214 fusion gene AML in our study is limited. It is still necessary to accumulate more samples for continuous research to more clearly prove the dynamic changes of DEK-NUP214 expression before and after transplantation. 　 　
Note:This article comes from the topic of "Molecular Diagnosis" in the fifth issue of Clinical Laboratory in 2021.　 　 　　

　　The washing machine bought six years ago broke down, but the consumer was delayed after the repair. It turns out that an important reason for the delay is that machine parts have been eliminated. After receiving consumer complaints, the Provincial Consumer Council intervened. Because there were no parts that could not be repaired, the manufacturer finally replaced the washing machine for the customer.

　　Home appliances purchased by citizens are normal for five or six years. However, the iteration of electrical appliances update is too fast, and a model is often discontinued after several years of production, and a new model is introduced. This often leads to the embarrassment that electrical appliances are out of order but there are no parts to repair, which has become a worry for many people.

　　In July this year, the Consumer Council of Guangdong Province received a total of 372 complaints from consumers, among which Internet services, sales services, life and social services ranked in the top three, and household electronic appliances ranked fourth. The Provincial Consumer Council emphasizes that after-sales service is the core competitiveness of electrical appliance manufacturers, and maintenance spare parts should be provided to consumers within 5 years after the products are discontinued.

　　Text/Guangzhou Daily All-Media Reporter Li Dalin Correspondent Yue Xiaoxuan

　　During the extended warranty period, the washing machine broke down and the manufacturer was sued for delaying maintenance.

　　Provincial Consumer Council: Maintenance spare parts should be provided within 5 years after the product is discontinued.

　　According to the Law on the Protection of Consumers’ Rights and Interests, the Law on Product Quality and other relevant regulations, the operator shall undertake the warranty, replacement, return or other responsibilities in strict accordance with state regulations or agreements with consumers, and shall not deliberately delay or unreasonably refuse. The Provincial Consumer Council said that in this case, the consumer purchased the extended warranty service of the washing machine, and the manufacturer was obliged to undertake the three-guarantee responsibility according to the state regulations within the promised time limit.

　　Secondly, according to Article 7 of the Provisions on the Responsibility for Repairing, Replacing and Returning Some Commodities: "Producers shall perform the following obligations &hellip; &hellip; Ensure to continue to provide spare parts that meet the technical requirements within five years after the product is discontinued &hellip; &hellip;” In this case, the manufacturer failed to provide relevant evidence that the product involved has been discontinued for five years, so it can be reasonably presumed that the product has not been discontinued or has not been discontinued for five years. Therefore, manufacturers should continue to provide repair spare parts for products, and should also ensure the supply of spare parts within 5 years after the products are discontinued.

　　Thirdly, according to Article 12 of the Provisions on the Responsibility for Repairing, Replacing and Returning Some Commodities: "If the manufacturer fails to supply spare parts within the validity period of the Three Guarantees and it has not been repaired for more than 90 days since the date of repair, the repairer shall indicate in the repair status that the seller will exchange the same model and specifications for the consumer free of charge. Then claim compensation from producers and suppliers according to law or handle it according to the purchase and sale contract. If the repair period exceeds 30 days due to the repairer’s own reasons, he will exchange the same model and specifications for the consumer free of charge, and the expenses will be borne by the repairer. " The manufacturer failed to continuously supply spare parts for the products involved, which caused consumers’ demands for maintenance to be delayed again and again. They should bear the corresponding legal responsibilities and take the initiative to exchange products of the same model and specification for consumers.

　　After-sales service of electrical appliances is the core competitiveness.

　　Although the manufacturer was satisfied with the results after the intervention of the Provincial Consumer Council, the after-sales service personnel had a negative attitude and even suspected of deliberate delay in the early communication with consumers, which deserves the attention and reflection of enterprises and also sounded the alarm for the industry.

　　The Provincial Consumer Council believes that in today’s saturated market and increasingly fierce competition, good after-sales service has become one of the core competitiveness of enterprise industry development, directly affecting the success or failure of enterprise operation and industry development. All relevant enterprises should attach importance to the quality of after-sales service, devote themselves to improving the quality of after-sales service, win the recognition and trust of consumers, and thus obtain the most fundamental support for long-term development.

　　Guangzhou consumer Mr. He bought a Haier washing machine in November 2012, and in July 2015, he bought an extended warranty service for Haier household appliances. The warranty period of the washing machine was extended to January 2019. In May 2018, the washing machine had failures such as dehydration failure and invalid buttons. Mr. He called Haier customer service for repair, and the customer service promised to send someone to check and repair, but there has been no news. Mr. He repeatedly called for reminders, and Haier customer service delayed the handling due to outdated spare parts and equipment, company relocation and other reasons. In desperation, Mr. He complained to the Guangdong Consumer Council and asked Haier to send someone to repair it as soon as possible.

　　After receiving the complaint, the staff of the Provincial Consumer Council immediately contacted Haier and asked Haier to handle it properly as soon as possible according to the purchase bill and extended warranty service card provided by Mr. He. Haier replied that the machine parts had been eliminated and could not provide maintenance service, so it was replaced for customers.

Food safety consumption tips

The long shelf life of canned food depends entirely on preservatives?

Open the lid (bag) to eat, delicious, convenient storage, recently, canned food has become a must-have item in many families’ inventory. However, an online micro-survey conducted by the reporter of China Consumer News recently on more than 200 consumers shows that most people’s comprehensive "goodwill" towards canned food is actually not too high because of the doubts that the food is not fresh, too many preservatives must be added, and too many nutrients are lost. But do these doubts really make sense? Let’s listen to experts in the field of food science.

Respondents’ cognition of canned food

Have you ever heard of soft cans?

In the era of relative scarcity of materials, canned food used to be a different flavor full of "luxury". In many memories of post-70s and post-80s, canned food is a nutritional product that can only be eaten on holidays or when you are sick.

Canned food was once a fancy food on the monotonous table of ordinary people. Almost all food can be canned. It is said that the selection of canned food is diverse, which can make people feel the richness of Manchu-Han banquet.

However, if your knowledge of canned food remains at the level of fruits, vegetables, fish and meat packed in tin cans or glass bottles, it may be a bit "outdated".

The National Standard for Food Safety "Canned Food" clearly defines canned food as a commercial aseptic canned food which is made of fruits, vegetables, edible fungi, livestock and poultry meat, aquatic animals, etc. as raw materials and processed by pretreatment, canning, sealing and heating sterilization.

Wu Xiaomeng, an associate professor at the College of Food Science and Nutritional Engineering of China Agricultural University, explained in an interview with the reporter of China Consumer News that the first meaning of canned food is sealing, and the second is to achieve commercial sterility. Its packaging can be either hard packaging represented by traditional metal cans or glass cans, or flexible packaging such as aluminum foil bags and high-temperature retort pouch, which is generally called soft canned food. For example, aluminum foil bagged vegetable bags in all kinds of self-heating foods, or prefabricated normal-temperature cooking bags such as Sichuan-flavored pork slices and fish-flavored shredded pork, all belong to the category of canned food.

Around 2000, as the earliest industrialized category in the food industry, canned food was gradually labeled as "unhealthy".

In 2003, an online list of "Top Ten Junk Foods Published by WHO" (canned food is on the list) was generally regarded as the fuse of canned food being cold among the people. Although this list has been fully falsified, it seems that it is difficult to open the tongue code of Chinese people, especially the traditional "hard cans" (metal or glass cans).

The data shows that although China’s canned food production ranks among the top in the world, the per capita consumption of canned food is less than 8 kilograms, and many people even consume less than two boxes a year.

Respondents’ purchase of canned food

Eating canned food is about the same as eating preservatives?

This micro-survey shows that 69.68% of the respondents rarely buy canned food, and 21.72% only buy it occasionally. At the same time, although 57.92% of the respondents believe that canned food is easy to store and suitable for hoarding at home, 32.58% of the respondents still believe that canned food "has a long shelf life and must have too many preservatives".

In fact, canned food is one of the few foods without preservatives or with the least amount of preservatives.

According to the National Food Safety Standard for the Use of Food Additives, except canned bayberry (propionic acid and its sodium salt and calcium salt are allowed to be added, the maximum dosage is 50g/kg), canned bamboo shoots, pickled vegetables, edible fungi and nuts (sulfur dioxide is allowed to be added, the maximum dosage is 0.5g/kg) and canned meat (nitrite is allowed to be added, the maximum dosage is 0.15g/kg), which requires very low dosage.

Then, cans that can be kept for 1 to 3 years or even longer at room temperature can be kept fresh by "frozen age".

Wu Xiaomeng told the reporter of China Consumer News that canned food actually protects food safety through sterilization technology and sealed storage. In most cases, food spoilage is caused by bacteria, molds and other microorganisms. Processing canned food by sterilization means such as high temperature and high pressure can kill a large number of these microorganisms. At the same time, processes such as venting and sealing can greatly reduce the oxygen content in food and containers, make some potential microorganisms in the containers grow stagnant, and block the passage of oxygen or microorganisms outside the containers into the containers, thus ensuring food safety. With the development of food processing technology, new technologies such as modified atmosphere sterilization and microwave sterilization have shorter heating time, lower energy consumption and more efficient sterilization.

Therefore, it is unnecessary to worry about too many preservatives in canned products. The "popular science" on the Internet that "eating canned food is about eating preservatives" is completely alarmist.

Canned food is not fresh and nutritious?

The survey found that among the respondents who "never bought" canned food, 52.94% thought canned food was not fresh.

Although some consumers began to consider choosing canned food that is easier to preserve because of epidemic prevention and control, hoarding goods at home and other factors, this did not change people’s understanding of its "stale".

In fact, the appearance of canned processing technology itself is to keep food fresh.

Wu Xiaomeng explained that foods such as meat and fish will rot quickly if they cannot be processed in time. If vegetables and fruits are not processed in time after picking, the nutrition will be lost continuously. Therefore, some brands with a relatively complete supply chain generally choose to adopt and make the ingredients at the mature stage with the largest output, and the whole material selection and processing process even takes less than 10 hours. Compared with the route of fresh ingredients from picking, transporting and selling to consumers’ refrigerators, there is no more nutritional loss.

Of course, some vitamins with low heat resistance will be lost in the process of canned food processing, but most nutrients will be preserved. Compared with the loss of nutrients caused by daily household processing and cooking vegetables, this loss is not more.

Sometimes, canned food may be beneficial to the maintenance of vitamins. For example, although canned tomatoes have been sterilized, most of the vitamin C content is still there when they leave the factory, and it is relatively stable. Another example is canned fish. After high-temperature and high-pressure sterilization, not only the meat quality and bones of the fish are softer, but also a large amount of calcium is dissolved out. The calcium content of a box of canned fish can even be 10 times more than that of fresh fish with the same weight, and minerals such as iron, zinc, iodine and selenium in fish meat will not be lost.

Why can’t "fat" cans be eaten?

In most cases, consumers are advised to buy products from regular manufacturers in large shopping malls or supermarkets, and judge the quality of canned food from the aspects of appearance, packaging, sensory quality, label and brand.

Wu Xiaomeng reminded that the cans of normal metal cans should have a complete shape, no deformation, no damage, no rust spots and a concave bottom cover; The center of the metal cover of the glass bottle can should be slightly concave downward, and the contents should be complete in shape, clear in soup and free of impurities when viewed through the bottle body.

What needs special reminder is that if you encounter the following situations, no matter how attractive the contents of the can are, don’t eat it.

One is canned "fat listening", that is, expanding cans. The main reason for tank expansion is that the inside of the can is polluted by microorganisms and produces gas. When these gases gather to a certain extent, the can will be deformed. Therefore, the can’s "getting fat" is a very obvious danger signal that it has gone bad.

Second, the canned packaging is leaking and moldy. In the process of storage and transportation, canned products will be deformed due to bumps and other reasons, and the seal of the can cover will leak, which will lead to the contact between the products in the can and the outside world, and microorganisms may take the opportunity to enter.

The survey found that 93.21% of the respondents had the right choice. However, about 7% of the respondents still thought that the collision caused by transportation was not a big problem and chose to buy and eat.

Wu Xiaomeng reminded that most canned meat and fruits and vegetables are not heavy, so it is recommended to eat them as much as possible after opening. If you can’t finish it, you should pour it into enamel, ceramic or plastic food containers, seal it with plastic wrap and store it in the refrigerator and finish it as soon as possible.

As for canned sugar sauces and jams, the sugar content is generally 40%-65%. Relatively speaking, it is not easy to deteriorate after opening, but it is still not careless. If you can’t eat it all at once, you should cover the jar, or pour it into other containers and seal it with plastic wrap, and then put it in the refrigerator for preservation. Try to eat it in two or three days. In autumn and winter, it can be stored for a few more days. (Reporter Li Jian)