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Figure 1: Uninoculated Starch Agar Plate. An uninoculated starch agar plate before flooding with iodine solution (A) and after flooding with iodine solution (B). (Archana Lal, Independence Community College, Independence, KS)

Figure 2: Growth of Bacillus subtilis on Starch Agar Plate Before and After the Addition of Iodine Solution. Growth of Bacillus subtilis on a starch agar plate before the addition of iodine solution (A) and after the addition of iodine solution (B).  After the addition of iodine, the clearing surrounding the bacterial growth indicates starch hydrolysis.  (Archana Lal, Independence Community College, Independence, KS)

Figure 3: Growth of E. coli on Starch Agar Plate Before and After the Addition of Iodine Solution. Growth of Escherichia coli on a starch agar plate before the addition of iodine solution (A) and after the addition of iodine solution (B). After the addition of iodine, the absence of a clearing surrounding the bacterial growth indicates no starch hydrolysis. (Archana Lal, Independence Community College, Independence, KS)

Figure 4: Growth of Staphylococcus aureus on Starch Agar Plate Before and After the Addition of Iodine Solution. Growth of Staphylococcus aureus on a starch agar plate before the addition of iodine solution (A) and after the addition of iodine solution (B).  After the addition of iodine, the absence of a clearing surrounding the bacterial growth indicates no starch hydrolysis.  (Archana Lal, Independence Community College, Independence, KS)

Figure 5: Growth of Micrococcus luteus on Starch Agar Plate Before and After the Addition of Iodine Solution. Growth of Micrococcus luteus on a starch agar plate before the addition of iodine solution (A) and after the addition of iodine solution (B).  After the addition of iodine, the absence of clearing surrounding the bacterial growth indicates no starch hydrolysis.  (Archana Lal, Independence Community College, Independence, KS)

Figure 6: Growth of Proteus sp. on Starch Agar Plate Before and After the Addition of Iodine Solution. Growth of Proteus sp. on a starch agar plate before the addition of iodine solution (A) and after the addition of iodine solution (B). After the addition of iodine, the absence of clearing surrounding the bacterial growth indicates no starch hydrolysis. (Archana Lal, Independence Community College, Independence, KS)

Figure 7: Growth of Pseudomonas aeruginosa on Starch Agar Plate Before and After the Addition of Iodine Solution. Growth of Pseudomonas aeruginosa on a starch agar plate before the addition of iodine solution (A) and after the addition of iodine solution (B). After the addition of iodine, the absence of clearing surrounding the bacterial growth indicates no starch hydrolysis. (Archana Lal, Independence Community College, Independence, KS)

Figure 8: Growth of Enterococcus on Starch Agar Plate Before and After the Addition of Iodine Solution. Growth of Enterococcus on a starch agar plate before the addition of iodine solution (A) and after the addition of iodine solution (B). After the addition of iodine, the absence of clearing surrounding the bacterial growth indicates no starch hydrolysis. (Archana Lal, Independence Community College, Independence, KS)

Figure 9: Growth of Bacillus subtilis, Escherichia coli, and Proteus on Starch Agar Plate Before and After the Addition of Iodine Solution. Growth of Bacillus subtilis (1), Escherichia coli (2), and Proteus (3) on a starch agar plate before the addition of iodine solution (A) and after the addition of iodine solution (B). After the addition of iodine, clearing surrounding Bacillus (B-1) indicates starch hydrolysis, while absence of clearing surrounding Escherichia coli (B-2) and Proteus (B-3) indicates no starch hydrolysis. (Archana Lal, Independence Community College, Independence, KS)

Figure 10: Growth of Enterobacter aerogenes on Starch Agar Plate Before and After the Addition of Iodine Solution. Growth of Enterobacter aerogenes on a starch agar plate before the addition of iodine solution (A) and after the addition of iodine solution (B). After the addition of iodine, there is no clearing surrounding the bacterial growth indicating a lack of starch hydrolysis. (Naowarat Cheeptham and Carolynne Fardy, Thompson Rivers University, Kamloops, British Columbia, Canada)

Figure 11: Growth of Citrobacter diversus on Starch Agar Plate Before and After the Addition of Iodine Solution Growth of Citrobacter diversus on a starch agar plate before the addition of iodine solution (A) and after the addition of iodine solution (B). After the addition of iodine, there is no clearing surrounding the bacterial growth indicating lack of starch hydrolysis.  (Naowarat Cheeptham and Carolynne Fardy, Thompson Rivers University, Kamloops, British Columbia, Canada)

Figure 12: Growth of Bordetella bronchiseptica on Starch Agar Plate Before and After the Addition of Iodine Solution. Growth of Bordetella bronchiseptica on a starch agar plate before the addition of iodine solution (A) and after the addition of iodine solution (B). After the addition of iodine, there is no clearing surrounding the bacterial growth indicating lack of starch hydrolysis. (Naowarat Cheeptham and Carolynne Fardy, Thompson Rivers University, Kamloops, British Columbia, Canada)

Figure 13: Starch Agar Incubated with Bacillus cereus and Escherichia coli Starch agar incubated for 24 hours at 37°C with Bacillus cereus (left) and Escherichia coli (right). After adding iodine, the iodine binds to starch if it is still present in the agar. A clear zone can be seen around the growth of Bacillus cereus indicating the production of the exoenzyme amylase, which digests starch to glucose leaving nothing behind in the agar for the iodine to bind. (Tasha Sturm, Cabrillo College, Aptos, CA)