Now is the season when crabs are on the market in large quantities. Recently, rumors about "needle-eye crabs" on the Internet have attracted attention, some people say that the crabs bought have "needle eyes", and there are rumors that these crabs have been injected with stimulants and water and other liquids, and illegal traders use needles to inject seawater, chemicals and other liquids into the crab shell, abdomen and other parts to achieve the purpose of maintaining the crab's freshness and increasing the crab's weight. Is this true?
To find out the truth of this rumor, two questions need to be answered:
Do crabs really have "needle eyes" on them?
Can crabs really be injected with liquid?
The small holes in the crab are not caused by water or glue injection
Luo Lin, researcher at the Institute of Fisheries Sciences, Beijing Academy of Agriculture and Forestry Sciences: "Needle-eye crab" I think it's a misunderstanding, the crab has to molt more than a dozen times, and the new shell is soft before it hardens, because the crab is a group of gatherings, so it may be pierced by the crab leg that has been molted and hardened on this soft shell, which looks like there is a hole, but it is actually not the eye of the needle. If you do prick it with a needle, it may break or not be so round and small, which is only the case if you get it when it is soft.
In fact, the "eye of the needle" on the body of the crab, which is itself "rampant and domineering", is likely to be caused by the crab's fight with its own kind during the natural growth process. In addition, crabs may also have some small wounds due to external forces during fishing and transportation.
Expert: Giving a crab a shot with water can cause the crab to die
It seems unlikely that the so-called "eye of the needle" on the crab is the eye that has been pricked with a needle. So, is it possible for crabs to be flooded? Experts pointed out that rashly injecting crabs with water will change the osmotic pressure of the organ environment, resulting in the loss of water and atrophy of the crab's organs or the swelling of water absorption and death, and the gains outweigh the losses. Therefore, the so-called "needle-eye crab" can never appear on a live crab.
Luo Lin, researcher, Institute of Fisheries Sciences, Beijing Academy of Agriculture and Forestry Sciences: First of all, because the muscle fibers of crabs are relatively delicate, its water retention rate is extremely low. If you draw water here and it will flow out, it can't hold water, and it has no effect on weight gain. Secondly, when you inject it, if you prick its internal organs, the crab will die, and the gain outweighs the loss. In addition, if you want to inject thousands of crabs, this is difficult to operate, how much labor you have to spend, and it may cause a large number of crabs to die.
Because we also took saline, thinking that this would not cause a change in osmotic pressure, we ended up dying without living overnight after the shot. And it can't be beaten much, a two-tael crab hits 2 ml of water, which is equivalent to 2 grams of water, and the crab is dead, adding 2 grams of weight does not make any sense to this crab.
According to experts, the transparent gelatinous substance in the crab's body is actually crab paste, which is the paragonal secretion of male crabs, that is, the sperm nest and semen, which is not only high in nutritional value but also delicious in taste. The crab roe comes from the female crab, which is the ovary of the female crab, and cannot be impersonated by water or glue. As for the hormone injections or stimulants, the claim is also untrue. These drugs are ineffective against crabs and can also damage water quality, leading to the death of crabs. Crab farming requires good water quality, and any harmful substances will affect its survival.
Luo Lin, researcher at the Institute of Fisheries Sciences, Beijing Academy of Agriculture and Forestry Sciences: If you can't survive with normal saline, then you will definitely not survive with glue. Because all animals have rejection, as a foreign body, the crab must have this immune system to fight the colloid, and if it can't fight it, it will definitely die.
Do out-of-season fruits and vegetables use a lot of pesticides?
In October, the cold in the northern region is getting stronger, and it is also the season when out-of-season fruits and vegetables are on the market. Recently, the rumor that "out-of-season fruits and vegetables will use a lot of pesticides, and eating them is harmful to health" has also attracted widespread attention, is this true?
Experts: Growing out-of-season fruits and vegetables in winter is less likely to be used than in summer
According to experts, the planting technology of off-season fruits and vegetables does not mainly rely on the massive use of pesticides, but through a series of scientific agricultural technology means. For example, the use of biological control, physical control and other means to reduce the use of chemical pesticides.
Liang Hao, Senior Engineer, Vegetable Research Institute, Beijing Academy of Agriculture and Forestry Sciences: In the process of off-season planting, we provide an environment that is relatively isolated from the external environment through the greenhouse, providing suitable temperature and humidity. But we don't do any modification to the plant itself, and because of this isolated environment, the risk of pests and diseases is reduced, so we use fewer pesticides.
Experts stressed that the scientific use of pesticides is a necessary part of agricultural production, compliance and rational use of drugs will not cause harm to the human body, and scientific management can also achieve less or no drugs throughout the process, coupled with government supervision, consumers do not have to worry about the safety of off-season fruits and vegetables.
Experts remind that the mainland has strict standards for pesticide residues, and when buying fruits and vegetables, you should choose formal channels, and pay attention to the origin and certification of fruits and vegetables. In addition, proper cleaning and disposal can also effectively reduce the risk of pesticide residues. For example, rinsing with running water and washing after soaking can effectively remove pesticide residues from the surface of fruits and vegetables.
Crush the rumors in your life
So, what other rumors related to life have been spreading on the Internet recently, continue to debunk ↓
Is hoarfrost on grapes a pesticide residue?
Myth: Hoarfrost on grapes is actually pesticide residues, so don't buy grapes with too much hoarfrost on them.
Truth: Grapes, blueberries, plums, etc. will have a layer of hoarfrost on the surface after ripening, which is the fruit powder produced by the fruit itself, which belongs to sugar alcohols, which are evenly distributed on the surface of the fruit and are insoluble in water. It is not only non-toxic, but also has certain nutritional value. In a way, the presence of hoarfrost is a sign of the freshness of the grapes.
Of course, if the farmer sprays pesticides during the grape growth process, there will also be a light layer of hoarfrost. To distinguish whether the hoarfrost on the surface of grapes is natural fruit powder or pesticide residues, the method is very simple: natural fruit powder is naturally evenly distributed, and does not cover the color of the grape skin itself, but only makes the grapes look more beautiful; The pesticide hoarfrost is unevenly distributed, and there may be droplet-shaped spots in it.
The more probiotics in yogurt, the better?
Myth: A certain Internet celebrity yogurt claims that "each cup of active probiotics is 500 billion", which is almost 100 times the recommended amount of probiotics per day (1 billion to 5 billion). This is because the probiotics in yogurt can promote gastrointestinal health, and the more you add it, the better.
Truth: The so-called probiotics refer to the normal flora isolated from animals, plants, and human bodies, and the live bacteria preparation produced after multiple processes. From a nutritional point of view, probiotics are beneficial for gut health, and some probiotics can also promote the metabolism of fats and sugars.
But more probiotics is not always better, and the body's flora should be kept in a balanced state. Excessive intake and supplementation of probiotics not only cannot have a positive effect on the human body, but may also disrupt the intestinal environment and produce serious negative effects, such as bloating, abdominal pain and even diarrhea.
(CCTV News)