Currently we have a single receiving area for our raw mat and pack mats. We have a plastic curtain located against our door. The door opens out to the front area of the processing plant. In a recent audit, one of our non-conformance was how the plastic curtain, placed against the door, doesn't really serve its purpose of keeping pests out. Because when the door opens, we also have to open the curtain to transport materials in and that means dust and flying objects can make its way into the plant.
A few possibilities I have seen are -
(1) receiving raw materials in a small ante-room prior main process area with the internal connection using self-closing doors,
(2) air curtains at entry,
(3) an industrial size overhead blower/cooler impeding entry of flies,
(4) using a (sealed) conveyor feed through the wall going directly into ante-room/process area.
Ideally the transport vehicle in (1) is taken entirely into the ante-room but this often not practical.
It likely also depends on the style which is used for raw material supply, eg piles heaped on trucks or ???