German cockroach is one of the most common roaches found in apartment houses, restaurants, and hotels. German cockroaches (eggs included), are brought inside or hitchhike on man's belongings, luggage, boxes or packages. A large German roach population will produce a foul odor. These roaches prefer moisture, food, and warmth. Sanitation measures are critical in controlling German roaches. German roaches can be a serious health hazard in restaurants. 

All it takes is bringing in one egg capsule, and in six months you will have an infestation.