pboo kem ปูเค็ม
Finding salted crab in a freezer section at an Asian market is as exciting as seeing snow falling in June. Because salted crab is hard to find, when I saw salted crab on a recent visit to the grocery, Som Tum, Salted Crab Chili Sauce and Green Mango Salad with Salted Crab flashed through my mind. I think of my mother's delicious Green Mango Salad with Salted Crab.
Salted crab is made from 2 types of crab, freshwater crab (ปูนา ) and mangrove tree crab (ปูแสม). Fresh water crab is commonly found on rice paddy fields. Mangrove crab lives in brackish water in mangrove forests. As the name suggests, the crab climbs on mangrove tree when high tide comes in. Both types of crab look very similar with blackish shell and sometimes reddish or purplish claws. The trapezoid shaped shell is about 1 1/2” x 2”.
When I was a kid there was always a health concern about eating salted crab. It could give you a stomach trouble and worse, parasites. My mother boils it first before using it in som tum. You can also microwave or boil it for 5 minutes. The parasites only live on freshwater crab, not the mangrove tree crab. Since salted crab is made from both types of crab, please cook the crab before using. I also like to boil it to tone down the saltiness and get the beautiful reddish shell. This doesn't degrade the taste in any way.
The salted crab comes in a foam tray, about 8 crab in a container in the freezer section. If you live in Los Angeles, Lax-C and other Thai markets have them. For other parts of the US, check Thai, Vietnamese and Lao stores for the crab.
Note: I was somewhat amused when I realized my friends tried hard not to pluralize the word "crab" when talking about food because they didn't want to refer to an STD.