Which of the following statements are True for handling of cells and culture media?

A. Cells and culture media should be free from contaminating microorganisms.

B. All cell culture materials should be maintained under sterile conditions.

C. All surfaces within the culture area should be non-porous to prevent adsorption of media and other materials that may provide a good breeding ground for microorganisms, resulting in the infection of the culture.

D. all of the above