Vegetable market is now "high-value" dry ginger tablets to detect sulfur dioxide exceeding 25 times - Database & Sql Blog Articles

We are in the vegetable market, it is not difficult to find that some dried vegetables "skin" is especially white, it seems to sell well, sales are also large, but these high "yan value" dried vegetables from time to time sent negative news. Many people say that common whitish dried ginger tablets are usually bleached with sulfur dioxide. In addition to dried ginger, dried yellow flowers, aniseed and other foods have also been exposed to sulfur dioxide problems. Previously, in the list of foods on the food safety office cloth in Beijing, there were five kinds of foods, such as dried yellow flowers, aniseed, ginger, white fungus and winter melon, and all of them exceeded the standard value of 18 because of excessive sulfur dioxide. Times. Recently, the Beijing News reporter purchased five kinds of dried ginger slices through the vegetable market and supermarkets, and sent them to the Beijing Zhiyunda Food Safety Testing Consumer Experience Center for testing. The test results showed that among the five kinds of dried ginger slices, the sulfur dioxide content of the four samples exceeded the standard, both of which were above 3000 mg/kg, and one of the samples had a sulfur dioxide content of 5208 mg/kg. According to the national mandatory standard GB2760-2014 "Food Safety National Standards for Food Additives", the content of sulfur dioxide in dried vegetables should not exceed 200mg/kg. According to this national standard, a sample in this experiment detected a sulfur dioxide content of 5208mg/kg, which exceeded the standard by 25 times. Dried ginger tablets are mostly used in cooking and dieting. Experts say that the use of sulfur dioxide in dried vegetables is mainly for bleaching, and it can play a role in antisepsis and mildew. However, eating too much food containing sulphur dioxide can cause symptoms such as difficulty breathing, vomiting, and diarrhea. In severe cases, it is more fatal. Detection reagent used in the experiment

Sulfur dioxide quick test box

Product Code: WSK-0104CZ

Specifications: 50 samples / box

Test samples: solid samples of fans, bamboo shoots, dried fruits, dried vegetables, canned mushrooms, daylilies, preserved fruits, candied dates, white fungus, dried sweet potatoes, dried plums, white sugar, fructose, and sucrose, and liquids such as wine and fruit wine.

Detection limit: 20 mg/kg

Storage conditions: 4-30 ° C in a cool dry place at room temperature

Shelf life: 12 months

Experimental results: Five kinds of dried ginger pieces were powdered, and 1.25 g of ginger powder was weighed and placed in an extraction bottle. After ultrasound, filtration, reagent addition, colorimetry, detection. In the colorimetric stage, after adding the detection solution to the sample solution, if the color of the solution turns purple, it means that it contains sulfur dioxide; if the color of the solution does not change, it means that it does not contain sulfur dioxide. The experimental results show that among the sample solutions in the five colorimetric tubes, all of the four kinds become purple, and three of them are dark purple. The final test results showed that the sulfur dioxide contents of the No. 1-5 dried ginger samples were: 4420 mg/kg, 45.7 mg/kg, 3438.4 mg/kg, 5208.6 mg/kg, and 4291.5 mg/kg, respectively. Experimental analysis: The experimental technicians introduced that after adding the reagent, three of the four purple-purified sample solutions turned dark purple, indicating that the three samples had higher sulfur dioxide content. During the experiment, when the food safety rapid tester was used for the first time, part of the solution showed that it could not be detected because the sulfur dioxide content was too high. Therefore, after re-dilution, the five samples were re-tested and the experimental results were obtained. According to GB2760-2014 "Food Safety National Standards for Food Additives", the maximum use of sulfur dioxide in dried vegetables is 200mg/kg. According to the national standard, among the five samples of dried ginger samples tested, the sulfur dioxide content of the four samples was unqualified. The highest content is 5208.6mg/kg, which is about 25 times higher than the standard. Why do there are more sulfur dioxide in dried vegetables? In this regard, Zhu Yi, an associate professor at the College of Food Science and Nutritional Engineering of China Agricultural University, said that the reason why the dried vegetables contain sulfur dioxide is mainly due to the sulfur smoked. After the sulfur is fumed, sulfur dioxide is produced and finally remains in the food. . For example, ginger that has not been smoked is not well preserved, and can cause insects and mold. Therefore, many of the dried ginger used as medicinal herbs and seasonings are sulphur-smelted. She said that according to national regulations, generally dried fruits with shells are allowed to be fumigated by sulfur; sulfur and non-shelled foods and vegetables are generally not allowed to be used, and the residue limit is strictly regulated. The reporter found that sulphur dioxide is called a cosmetic additive for food. It has bleaching, antiseptic and anti-oxidation functions. It can be used reasonably as a food additive, but the sulphur dioxide remaining in food cannot exceed the standard. Long-term low-dose exposure to sulfur dioxide may cause respiratory system damage to some sensitive people, such as rhinitis, pharyngitis, bronchitis, bronchial asthma, emphysema, etc. However, if the residual sulfur dioxide in the food does not exceed the standard, it will have little effect on the human body. According to public information, excessive sulfur dioxide residues not only damage vitamin B1, but also affect the body's absorption of calcium, and also have a stimulating effect on human gastrointestinal tract. After eating sulfur dioxide exceeding the standard food, there will be symptoms such as dizziness, vomiting, nausea, diarrhea, and general malaise. Can other methods be used instead of sulfur dioxide? Zhu Yi said that using sulphur fumigation to make food "white" is one of the lowest cost and good results, so it has been used until now and it is difficult to ban. Of course, in addition to sulfur, there are other ways. For example, the standards for the use of ingredients and herbs are higher, and it can also be treated as “sulphur-free”. The storage conditions such as ventilation and drying are good, and sulfur treatment is not required. At present, many export medicinal materials are sulfur-free. In fact, freeze-drying, microwave drying, infrared treatment and other methods can also play the role of storage, drying, insect proof and mildew proof. But these have higher requirements for technology and require technical guidance and popular science promotion. In this test sample, only the obviously yellowish No. 2 dried ginger did not exceed the standard. Zhu Yi also suggested that the first is the smell of dried vegetables with obvious pungent smell. The chances of containing sulfur dioxide are higher. It is best not to buy. The second is to observe whether the color of the product is abnormal. If there is obvious whitishness and whiteness is uniform, it is also necessary to be vigilant.