Type of base media used will be determined by organisms being tested 1. Prepare base media according to protocol - Before autoclaving add 4g/L of colloidal chitin. - colloidal chitin preparation - check pH and adjust to 7.2 - Or to pH specified based on organism being tested - if unknown start at pH 7.2 2. Autoclave media for 30min at 121C and 15psi 3. Allow media to cool to ~65C 4. Briefly, and gently, stir media before pouring to ensure chitin is evenly distributed. 5. Pour ~10-15ml of media into petri plates until all media has been poured. 6. Cover plates and allow to cool and dry overnight before packaging in bags and storing on shelf.