This dish in my memory is a Teoh Chew dish, as you said is a
Teoh Chew Cold Crab dish.
Why people have this cold dish ?
Most people knew that Dead crabs are non edible, you will get
food poisoning if you are unlucky. And the flesh of dead crab is
horrible, no one would eat it.
I heard from OLD people. This dish started when Teoh Chew
fisherman wanted to cut loss as dead crab had to be thrown. They
realized the steamed crabs kept in the ice box still edible and the
flesh still tasty while they were on the ocean. This is commonly
practiced in western countries as well. The fisherman steams crabs,
lobster etc in the Ocean.
Wash it before you steam it and quick chilling. There is a trick
that you steam it and yet the legs and arms remain attached.
Cold Crab dish is one of the famous dish at Ban Heng
Restaurant.
To me, this dish is not worth the $. Some would still get
food poisoning if the dish is not well handled. Germs will start
populating at 5 - 65 deg celc.