For molluscan shellfish, pool 12 animals. Blend 90 sec with an equal vol of PBS (1:2 diln) (4). Prepare a 1:10 dilution by transferring 20.0g (weighing is recommended because air bubbles in the 1:2 dilution prevent accurate volumetric transfer) of the 1:2 to 80 ml of PBS. Additional 10-fold dilutions can be prepared volumetrically (i.e. 1ml of 1:10 to 9.0ml of PBS for a 1:100 dilution.