Section 785.530  Dryers

a)         Spray Dryers:  Spray dryers shall be of a continuous discharge type and all product contact surfaces shall be of stainless steel or other equally corrosion-resistant material.  All joints and seams in the product contact surfaces shall be welded and ground smooth.  All dryers shall be constructed so as to facilitate ease in cleaning and inspection.  Sight glasses or ports of sufficient size shall be located at strategic positions to assure proper drying operations.  Dryers shall be equipped with air intake filters and with air intake and exhaust recording thermometers.  The filter system shall consist of filtering media or devices that prevent the entrance of foreign substances into the drying chamber.  The filtering system shall be cleaned or component parts replaced as often as necessary to maintain a clean air supply.  In gas-fired dryers, precautions shall be taken to assure complete combustion.  Air shall be drawn into the dryer from sources free from odors and smoke, dust, or dirt.

b)         Roller Dryers:   

1)         The drums of a roller dryer shall be smooth, readily cleanable and free of pits and rusts.  The knives shall be maintained in such condition so as not to cause scoring of the drums.

2)         The end boards shall have an impervious surface and be readily cleanable.  They shall be provided with a means of adjustment to prevent leakage and accumulation of milk solids.  The stack, hood, the drip pan inside of the hood and related shields shall be constructed of stainless steel and be readily cleanable.  The lower edge or the hood shall be constructed so as to prevent condensate from entering the product zone. The hood shall be located and the stack of adequate capacity to remove the vapors.  The stack shall be closed when the dryer is not in operation.  The augers shall be of stainless steel or properly plated, and readily cleanable.  All air entering the dryer room shall be filtered to eliminate dust and dirt.  The filter system shall consist of filtering media or device that prevent the entrance of foreign substances into the drying room.  The filtering system shall be cleaned or component parts replaced as often as necessary to maintain a clean air supply.  All dryer adjustments shall be made and the dryer operating normally before food grade powder can be collected from the dryer.