Processing of candidate reference materials often includes a sieving step when manipulating powders. Due to an increasing demand from laboratories, more and more fat-rich and oily materials have to be processed into reference materials, especially in the GMO and mycotoxin fields. Generally,
sieving of fat-rich powders results in gradually blocked sieves and increased oil/fat release, and in the worst case, severe clogging.
JRC-IRMM experts tackled this problem by developing a method for cryogenic sieving using liquid nitrogen. This new approach made it possible to process the recently released certified reference material (CRM) ERM-BF434, the world-wide first CRM for a GMO rapeseed powder. The new method has the potential to be used for sieving of materials even if they are not “free flowing” at room-temperature, e.g. GMO rapeseed powders and pistachio powders.
Further refinements of a cryogenic sieving system are now being done in collaboration with a manufacturer of industrial sieves.
|Example shown of sieving|
pistachio powder at room
in severely clogged screen.
|The same screen is shown after|
cold-sieving of pistachio
powder without clogging.