In recent years, there have been many news reports about "sugar-added sea cucumbers". How can you tell the difference?
Look at the color. Is it black or not?
Good quality sea cucumbers should be grayish-brown or dark brown, with a lustrous surface, and the internal organs should be gray or white. Inferior sea cucumbers with added sugar, on the other hand, are jet black, have a very deep color, and their internal organs turn red or black.
Look at the shape. Squeeze it.
A good sea cucumber has a well-proportioned body, firm flesh, sharp and intact spines, and feels relatively hard, making it difficult to bend. A sugar-added sea cucumber is the opposite: its body bends easily, but the spines are straight.
Apply some heat and bend it.
Sugar melts easily. When buying a sea cucumber, you can try to warm it up. The simplest way is to rub your hands together to generate heat, then hold the sea cucumber in your palm to warm it up for a while. Once it's warm, hold both ends and try to bend it. If you find that the sea cucumber bends and softens, and this change becomes more pronounced with higher temperatures, it means sugar has been added.