Starch Plate Test:

If given a description of results, know what that means about the organism’s ability to hydrolyze starch 

• SELECTIVE, NO everything grows 

• DIFFERENTIAL, YES for organism that can break down starch into glucose

If given the details of an organism's ability to hydrolyze starch, be able to describe how the results should come out (presence/absence of a halo or clearing around the growth) 

• Positive starch: clear halo can break down starch 

• Negative starch: black or dark color can’t break down starch

Know the name of the reagent needed to read the results of a starch plate test (what you have to add) 

iodine

After adding the appropriate chemical/reagent to an already inoculated and incubated starch plate, you notice the entire plate is solid black/purple when you hold the plate up to the light and observe it from the bottom. What does this tell you about the organism?

Negative for starch hydrolysis 

After adding the appropriate chemical/reagent to an already inoculated and incubated starch plate, you notice a clearing or halo of light around where the bacteria is growing when you hold the plate up to the light and observe it from the bottom. What does this tell you about the organism?

Positive for starch hydrolysis