The experiment of adding water to lake crabs by online vendors: death after 8 minutes of water injection

When the autumn wind rises, the crab's feet itch, and it's a good time to eat lake crabs. But not long ago, there were rumors on the Internet that some illegal traders injected water to lake crabs in order to gain weight and sell a lot of money. People began to worry, this delicious and nutritious lake crab can still climb to our table safely? In order to solve this mystery, yesterday, Hangzhou Food Safety Supervision Association commissioned a third-party testing agency, Zhejiang Justice Inspection Center, to do the experiment of water injection crab. The reporter followed the whole process and made a detailed record.

Experimental materials: 4 fresh lake crabs. Among them, No. 1 male crab weighs 125.74 grams, No. 2 male crab weighs 123.10 grams, No. 1 female crab weighs 87.60g, No. 2 female crab weighs 82.06g.

Experiment 1: inject clear water

Experimental method: use a syringe to inject water (clear water) from the back of No. 1 female crab, a total of 2 needles, 5 ml per needle

Injecting water from the abdomen of No. 2 female crab is also 2 stitches, 5 milliliters per needle.

Experimental observation: during water injection, water constantly flows out of the water injection hole or the mouthparts of lake crabs.

After water injection, the weight gain of both crabs was only about 4 grams.

After 2 minutes of water injection, the vitality of the two crabs decreased significantly.

After 8 minutes of water injection, the No. 2 female crab injected water from the abdomen died, and the No. 1 female crab injected water from the back had a slight reaction in the eyes.

Expert explanation: the relevant person in charge of Hangzhou Market Supervision and Administration told reporters that crabs, like people, have an electrolyte solution in the body, which destroys its normal concentration after injecting clear water. This is like a hanging injection, which must be injected with isotonic solution (which refers to a solution whose osmotic amount is equal to that of plasma. Such as 0.9%NaCl solution and 5% glucose solution. The solution that is lower than the osmotic amount of plasma is called hypotonic solution, in which cells can edema or even rupture. The solution that is higher than the osmotic amount of plasma is called hypertonic solution, in which cells can be dehydrated and shrunk. If you get clear water in, can there be no problem? It is the same reason that lake crabs die quickly when they are injected with water.

Experiment 2: injection of normal saline

The reporter asked: since this is the case, if the lake crab is injected with isotonic solution, will it not die?

Continue the experiment: take the physiological saline (0.9%NaCl solution) used in the experiment and inject it into the back of No. 1 male crab, a total of 2 needles, 5 ml per injection

Injected from the abdomen of the No. 2 male crab, it is also 2 stitches, 5 ml per injection.

During the experiment, there was no obvious water overflow during injection, which may be the reason for the large body capacity of male crabs.

After injection, the weight of the two crabs increased by about 8 grams, and there was no significant change in the state of the two crabs 2 minutes after injection.

Eight minutes after injection, the vitality of No. 2 male crab injected from abdomen was poor, and that of No. 1 male crab also decreased.

After 10 minutes of injection, the two crabs have basically lost their vitality.

Expert explanation: injected with normal saline, the lake crab will also lose its vitality and will die soon. Because 0.9%NaCl solution is isotonic solution for human body, what kind of isotonic solution can be used for lake crab should be known only by professional researchers. If ordinary small traders want to use this isotonic solution to gain weight for lake crabs to sell a few more money, the loss outweighs the gain.

Experimental results: whether injected with water or normal saline, lake crabs will lose their vitality or even die in a short time. Obviously, it seems unreliable to use these two methods to make dirty money. In that case, will there be other ways, the relevant departments will continue to pay attention to and follow up the inspection.