Product Company Principle Autoplater Spiral Biotech Spreads a liquid sample on a surface of a Petri dish with a Bethesda,Md.USA concentration gradient.Count manual or electronic. Completely automatical system. Whitley automatic Microbiology International. See above Spiralplater Rockville.Md.USA Petrifilm system 3MCo. The liquid sample is directly applied on a film with embedded St.Paul,Minn.USA rehydratable nutrients,incubated for 24-48 hours and counted using a Most Probable Number (MPN)conversion table. IsoGrid system QA Laboratories, The probe is filtered through a square filter with hydrophobic San Diego Calif.USA grids and incubated to allow colony growth and counted. SimPlate system Biocontrol. The liquid sample is added and mixed with nutrients and Bellevue,Wash.USA indicators and evenly distributed in a microplate.During incubation fluorescent enzyme substrate is hydrolyzed by the bacteria.The number of fluorescent wells is counted and analyzed using a MPN conversion table. Redigel system 3MCo. The probe is added to a ready-to-use tube containing a liquid St.Paul,Minn.USA pectin gel with nutrients.Pouring into a calcium-coated Petri dish leads to hardening of the complex resembling normal agar,that can be incubated and counted