Screening Protein Powders for Foreign Materials

We manufacture protein shakes and our concern is non-magnetic foreign materials (wood, paper or plastic) in the bags of protein getting dumped into the blender.  We considered screens, but any screen with a small enough mesh to prevent foreign particles would not allow the protein powder to freely pass through.  These would require someone working the protein thought the mesh which would make this a very time consuming process.  Any mesh that would allow the protein powder to easily pass would also let foreign bodies pass through. Considering the large batch sizes, the solution must be something that does not slow the process. I know there must be other companies who have to deal with this challenge and has a solution.

dsparkman,

Are you dry screening or is this it in a slurry?  We manufacture starch powders and for our slurry filters we are using 23 or 300 micron (.025-.3mm) and in our sifter pre-metal detector we use a 45-60mesh (.355-.25mm) screen.  We run products with a bulk density anywhere between .1-.6 g/cc, .6 is pretty normal.  We also have a 3ft length of flexible plastic that we put in the sifter and if moves around to aid product movement.  What types of screens are you currently using?  For non metallic items that are less than .355 mm are not much of a hazard i.m.o.

G

We are using dry powders.  Haven't used any screens to date and haven't had any problems or complaints.  But we would like something in place.

D

We use a Sweco brand and they are out of Kentucky.