Q1. You have collected an air sample by using a pump which draws 1cfm (cubic foot/minute). You collected a sample for 5 minutes directly on appropriate microbiological media. Following incubation you observed an average of 55 colonies on the plates. How various organisms are present in 1m3 of air given these conditions?

Q2. We are told that every surface we touch is teeming with bacterial cells, and bacteria are found in the pools we swim in, water we wash with, and on the hands of friends. Why don’t we always have problems with bacterial infections all over our bodies?