The corn is fluttering and the grain is hanging its head. In the harvest month of October, autumn delicacies such as hairy crabs and chestnuts gradually appear on the dining tables of every household. At the same time, many rumors about food have also begun to surface – hairy crabs are soaked in antibiotics to prevent disease, freshly slaughtered pigs, cattle and sheep have the most delicious meat, sugar-fried chestnuts are added with paraffin, eating water spinach will cause cramps… these are unreliable Pu’s remarks were widely spread online.
Today, reporters from Science and Technology Daily will take stock of October’s rumors one by one to help you clear away the fog and find the truth.
Are hairy crabs soaked in antibiotics to prevent disease?
Fact: Using antibiotics is detrimental to crab growth
Every year when hairy crabs are on the market, rumors related to them will “resurface”. Among the many “old rumors”, the rumor that “hairy crabs are soaked in antibiotics to prevent disease” is the one that worries consumers the most, fearing that eating “antibiotic hairy crabs” will affect their health.
However, this rumor has no scientific basis in the opinion of Zhang Shulin, a professor at the Fisheries College of Tianjin Agricultural University.
“The hairy crabs that people call are Chinese mitten crabs. Diseases of hairy crabs need to be prevented first, combined with prevention and treatment. If antibiotics are sprinkled into the water to prevent diseases, it is a bit like giving vaccinations to harmful bacteria in the water. It may cause Harmful bacteria develop immunity to antibiotics, thereby developing drug resistance.” Zhang Shulin further said that once harmful bacteria become resistant, when the bacteria make hairy crabs sick, and then feed antibiotics to hairy crabs, the efficacy of the medicine will be greatly reduced, and extremely harmful to the health of hairy crabs. This greatly increases the difficulty of subsequent treatment. At the same time, broad-spectrum antibiotics can not only kill harmful bacteria, but also beneficial bacteria, destroying the ecological balance of the water environment, which is not conducive to the normal growth of hairy crabs.
“Currently, the country has very strict management of the use of inputs for aquaculture. The Ministry of Agriculture and Rural Affairs has issued the “Notice on Strengthening the Supervision of Inputs for Aquaculture” to speed up the establishment of a white list system.” Zhang Shulin emphasized that if hairy crabs are sick, they can be used The drugs on the white list are mixed into bait in a fixed amount for treatment, but the use of inputs outside the white list is strictly prohibited. Once the local agriculture and rural (fishery) department discovers illegal use, it will investigate and deal with it in accordance with the law, and those suspected of committing crimes will be transferred to the judicial department for criminal responsibility.
So, how to help hairy crabs prevent various diseases?
Zhang Shulin introduced that before breeding hairy crabs, you must first select excellent disease-resistant varieties through modern biotechnology. At the same time, we must plant aquatic plants and use indigenous microecological preparations to purify water quality, improve the ecological environment of the pond, and block the spread of germs.
Which meat from freshly slaughtered pigs, cattle and sheep is the most delicious?
Truth: Containing a large amount of lactic acid affects the taste
In autumn, all kinds of meat are indispensable. In many people’s minds, the meat of freshly slaughtered pigs, cows, and sheep is the most tender and delicious.
In this regard, Wang Hao, a professor at the School of Food Science and Engineering at Tianjin University of Science and Technology, said in an interview with a reporter from Science and Technology Daily that after pigs, cattle, and sheep are slaughtered, their normal metabolism and blood oxygen supply stop immediately, and the glycogen stored in the muscles stops. It will be degraded into a large amount of lactic acid, which will coagulate myosin, cause muscle contraction, and make the meat stiff.
The meat of cattle will become stiff 2.5 hours after being slaughtered, while the meat of sheep and pigs will become stiff 1 hour after being slaughtered. Meat in the stiff stage is not suitable for processing. This type of meat is hard, loses a lot of juice, and is not easy to be cooked.
Therefore, after pigs, cattle, and sheep are slaughtered, it is best to detoxify their meat first. Pork needs to be hung in an environment of minus 5 degrees Celsius for 24 to 36 hours to deacidify; beef and mutton need to be placed in an environment of 2 degrees Celsius for 1 to 2 days to deacidify. In addition, these meats produce an enzyme during the acidification process.
“Meat that has been deacidified has better nutrition and taste.” Wang Hao explained that first of all, in terms of nutrition, under the action of enzymes, the protein of deacidified meat is broken down into amino acids, which is easier to be absorbed by the body. Secondly, in terms of taste, after acid removal, the muscles and connective tissues change from stiffness to relaxation, and the meat is easier to cook and taste.
In addition, the growth and reproduction of most microorganisms in sour meat are inhibited, and the number of harmful bacteria such as Clostridium botulinum and Staphylococcus aureus is greatly reduced. At the same time, a dry film will form on the surface of the acid-depleted meat, which can prevent the invasion of external microorganisms, thereby improving the storage resistance of the meat.
Are paraffin wax added to the sugar-roasted chestnuts?
Truth: The state strictly prohibits such additions
As the saying goes: “Carambola in July and hawthorn in August, chestnuts in October laugh haha.” Every year when the chestnut eating season comes, the topic of “candied chestnuts with paraffin added” will be revealed and will be on the hot search for several days again.
In this regard, Wang Hao said that adding paraffin is not allowed during the frying process of chestnuts.
As a mineral oil, paraffin is a mixture obtained by the fractionation of crude oil. Paraffin wax is divided into industrial grade and food grade. According to the requirements of the “National Food Safety Standards for the Use of Food Additives” (GB 2760-2014), food-grade paraffin can only be used as a processing aid. “According to national regulations, food-grade paraffin can be used in the food production process only when it has to be used. Paraffin functions as a release agent and is used in candies and baked goods. It is not necessary to use it for frying chestnuts. Therefore, it is not allowed to be added during the roasting process of chestnuts.” Wang Hao explained.
When making candied roasted chestnuts, adding paraffin wax will make the color of the chestnuts brighter, thereby attracting consumers to buy them. Therefore, in the past, some merchants illegally added paraffin, even industrial-grade paraffin, during chestnut frying. This kind of paraffin contains many impurities, including polycyclic aromatic hydrocarbons, which are strong carcinogens and can easily cause damage to human brain nerves and liver organs. Today, under the supervision of relevant national departments, such illegal additions are rare.
“It is inappropriate to add paraffin during the frying process of chestnuts. However, consumers do not need to be too nervous. Paraffin will only wrap around the skin of chestnuts, and we will peel them when eating chestnuts. If the consumption is not huge, it will be ingested by the human body. There is very little paraffin.” Wang Hao suggested that consumers should not pursue the “appearance” too much when buying sugar-roasted chestnuts, and should not buy chestnuts that are too smooth to the touch.
Will eating water spinach cause cramps?
Truth: This statement has no scientific basis
Water spinach is a common vegetable with very high nutritional value. But last month, water spinach was dubbed a “cramp vegetable” by some people on the Internet. Some netizens said that “eating water spinach will cause cramps,” and many people believed it.
In this regard, Wang Hao said that there is currently no scientific evidence that water spinach is related to cramps.
Cramp is the common name for muscle spasm. Generally speaking, cramps in the human body are caused by a sudden uncontrollable contraction of muscles and are usually related to factors such as excessive exercise and electrolyte imbalance in the body.
There are many causes of cramps, but the reason why eating water spinach is rumored to cause cramps is mainly due to the high oxalic acid content in water spinach. After oxalic acid combines with calcium, it will form calcium oxalate, which affects calcium absorption. When the concentration of calcium oxalate is high, the level of calcium ions in the blood will decrease. When the calcium ion content in the blood is too low, it will easily lead to increased muscle excitability, and muscle spasms will occur if slightly stimulated.
“For ordinary people, when the calcium ion content in the blood is too low, the calcium element in the bones will be replenished, so there will basically not be too little calcium ion content.” Wang Hao explained.
Not only water spinach, but also many vegetables have high oxalic acid content, such as spinach, celery, cabbage, etc.
“When cooking water spinach and other vegetables with high oxalic acid, it is best to blanch them first. This operation can remove more than 95% of the oxalic acid. At the same time, we must achieve a balanced diet every day. When eating vegetables rich in oxalic acid, you can Pair it with foods high in calcium.” Wang Hao suggested.