Because a working factory employee cafeteria, not lap they come out periodically, disposable food for several days. Thus, there is a buildup of food particles. Making the gate value oil & Grease exceeds the standard.
Because employees working on their lap, not cafeteria food is left out for days. As a result, the accumulation of food debris. Gates made the oil & Grease outsized.
Because the factory staff work in the cafeteria is not the food out of a scoop for several days. Therefore, the accumulation of food makes you the oil & Grease exceeding standard.