- Centrifuge spore suspension at 300 G for five minutes to form a spore pellet which contains two strata, the upper supernatant fluid and the lower stationary phase containing most of spores.
- Transfer supernatant fluid to another tube using a pipette, and resuspend lower stationary phase using sterile water.
- Centrifuge supernatant for five minutes at 300 G to pellet the spores, and again transfer supernatant fluid to another tube and resuspend the lower stationary phase.
- Repeat procedure three times.
- Combine resuspended lower strata created from each centrifugation to yield a spore suspension with a purity greater than 99 % (Cole, 1970).