H.A.C.C.P. properly applied in the snack industries is a pretty efficient tool limiting health and safety risks for final consumers. In most snack pellets and pasta factories the first C.C.P. is related to flours moving from silos or big bags or paper bags through flour handling systems to extruders. Thus, flour represents an ideal vehicle carrying small metal pieces. Static, rotary or other kind of filtering systems are not enough. Strong magnets must be installed in order to safely avoid metal pieces from moving to final extruded products.