8/30/2016 Rapid Methods Based on Diluting the food sample Traditional Methods Traditional-manually pipetted Biochemical profiles differentiate and identify Rapid bacteria 1.manual diluters Bacterial isolation is required 2.automated plating systems Separation from food matrix that attain 1000-fold Traditional-sterile blender cups dilution on one plate Rapid-sterile bags and Stomacher Products that replace the Counting colonies standard agar plate Traditional method Petrifilm system >time consuming >rehydratable nutrients and a gelling agent embedded in >open to human error disposable cardboard -Rapid-colony counting >1 ml of diluted bacteria used systems to rehydrate the film >scanners and software >specialized for specific >images may be stored microbes E.coli=49(blue colonies with gas)beta- glucuronidase Total coliform=87(red and blue colonies with gas)8/30/2016 5 Rapid Methods Based on Traditional Methods Biochemical profiles differentiate and identify bacteria Bacterial isolation is required • Separation from food matrix - Traditional – sterile blender cups - Rapid – sterile bags and Stomacher • Diluting the food sample - Traditional – manually pipetted - Rapid 1. manual diluters 2. automated plating systems that attain 1000-fold dilution on one plate • Counting colonies - Traditional method time consuming open to human error - Rapid – colony counting systems scanners and software images may be stored • Products that replace the standard agar plate - Petrifilm system  rehydratable nutrients and a gell ing agent embedded in disposable cardboard  1 ml of diluted bacteria used to rehydrate the film  specialized for specific microbes E. coli = 49 (blue colonies with gas) beta￾glucuronidase Total coliform = 87 (red and blue colonies with gas)