Crab traders use this device to know whether the crab has much or little roe, without hurting the crab.

Unlike raw shrimp, crab products are inspected and evaluated for quality mainly based on two factors: weight and roe ratio. These factors are proportional to the value of commercial crab roe; the heavier the crab, the higher the roe ratio, the higher the purchase price and vice versa.

Thương lái mua cua dùng thiết bị này là biết được cua nhiều hay ít gạch, lại không làm cua đau - Ảnh 1.

Traders use lights to check and evaluate the quality of crab roe before buying.

Normally, to determine the weight of commercial crabs, the most commonly used method is to use scales to measure and become a common convention. But to check and evaluate the ratio of commercial crab roe, there is no specific and clear standard. Checking by external senses for color, combining using a small knife to scratch the crab's apron to look inside to determine and evaluate the quality of the roe, the accuracy is not high.

Because each person has a different perception, there are often disputes between sellers and buyers. Because crabs with roe are of good quality, the purchase price is very high; and for crabs with low roe ratio or also known as not having enough roe, the purchase price is reduced to 60% or equal to the price of the same crab, equivalent to 50% of the value of quality crabs with roe.

To create fairness, limit disputes about the quality of commercial crabs, protect the rights of sellers and buyers, recently, farmers and crab buyers have innovated the way to check and evaluate the quality of commercial crabs. They no longer use a knife to cut the crab's apron to look inside, but use LED lights to evaluate.

This method will be quite accurate, because the LED light when shining on will penetrate the crab parts, clearly seeing every detail inside, especially for the crab's roe, the LED light cannot penetrate so that area becomes a dark area. Therefore, when using LED light to check, the more dark areas are detected, the higher the roe ratio, which means the greater the value, and vice versa.

Mr. Tran Minh Tam, Duc An hamlet, Phu Hung commune, said: “Every day, many traders come to the house to buy commercial crabs, on the basis of mutual agreement. When a trader comes to buy, the people allow the trader to use a knife to cut the crab's apron to check and evaluate the quality of the crab's roe to set a price. If the price is not agreed upon, the people call another trader, they also continue to use a knife to cut the crab's apron to check, and like that, the health of the crab is affected. But now, we can use a light to check freely, and the health of the crab is not affected.”

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