Since we like eating fresh crab so much, I decided to do a bit of research on how to kill and clean crabs. The RSPCA as well as the NSW department of primary industries (agriculture) both have recommendations on the Humane Killing of Crustaceans. The method is divided into 2 phases.First, the salt water/ice slurry method: It is recommended that the creature is immersed in a salt water/ice slurry for 20min before pithing, boiling or cutting. This ensures that the animal is unconscious and will not suffer during the killing process. Do not immerse in fresh water as it will cause the cells to swell (osmotic shock) and the meat will be tasteless.
Once the creature is immobilised by the cold, kill it by destroying both the nerve centres. A crab has 2 nerve centres - one immediately behind the eyes and one at the rear end, just above the point of the apron. A sharp object such as a screwdriver or sharp scissors can be used.
Armed with this knowledge, I went to KK market and bought 2 huge Sri Lankan crabs. Robert the "crab man" said that the best way to keep them alive was to place them in a pail and cover them with damp newspaper. This is what I did and to get them drowsy, I added a tray of ice cubes as well, to lower the ambient temperature.
Kill the crab by pithing it through both nerve centres - picture here shows the posterior nerve centre being destroyed. Once the crabs are dead, wash them under a running tap and scrub away all mud, algae and dirt from the shell.
Cleaning the crab: grab the apron - this is the triangular shaped structure on the undersurface. Peel it away and remove the carapace or top part of the shell. This takes a little bit of finger strength.Once the shell is removed, the gills can be seen - these are inedible and must be removed. Use your fingers or a pair of scissors. Scrub thoroughly.
Now it can be sectioned and legs removed at the joints. Crack the pincers and legs with a mallet before cooking.
