Dey engley neutralizing agar is use to isolate the microorganism from the different surfaces like cleanroom walls, laminar air flow, Sterile garments and accessories too. Below is the method for environment monitoring through Dey engley neutralizing contact plate. 1) Open the lid of plate and touch it to the sample surface. 2) Gently press at the central and close the lid. 3) Disinfectant touch surface area 4) Send the plates for incubation 5) Observe the results