microbiological testing

• Quick and easy to determine. Accurate counting.
• No need of complicated dilution and time-consuming steps.
• Small and delicate dry medium is convenient for storage and culturing.
• Small scale of sample can diffuse automatically.
• Compact dry can be kept in room temperature for one year.
• It is easy to pick colonies according to the color change of the medium.

Total Count

• Since tetrazolium salt is added in the medium, the colonies will be red and is easy to determine.
• Steps:
• 1. 35 ± 2 ℃ incubation for 48 hr
  2. Count red colonies

EC ( E. coli, Coliform)

• E. coli and Coliform are presented in deferent colors according to the substrate of color presenting enzyme, Magenta-GAL and X-Gluc. It is easy to determine the colonies of E.coli or coliform by colors.
• Steps:
• 1. 35 ± 2 ℃ incubation for 24 hr
  2. Count blue colonies as E. coli and total colonies as coliform.

CF (Coliform)

• E. coli including E. coli O157 are presented in blue by adding X-GAL, which is the substrate of color presenting enzyme, into the medium.
• Gram negative bacteria other than E. coli are presented in white.
• Steps:
• 1. 35 ± 2 ℃ incubation for 24 hr
  2. Count blue colonies as coliform.

X-SA (Staphylococcus aureus)

• Staphylococcus aureus are presented in light blue or blue according to the substrate for color presenting enzyme.
• The bacteria other than Staphylococcus aureus are presented in white.
• Steps:
• 1. 35 ± 2 ℃ incubation for 24 ± 2 hr
  2. Count light blue or blue colonies as SA.

VP (Vibrio parahaemolyticus)

• Reformed according to TCBS agar. Inhibit the growth of bacteria other than Vibrio.
• V. parahaemolyticus are presented in blue according to the substrate of color presenting enzyme. Bacteria other than VP are presented in white.
• Steps:
• 1. 35 ± 2 ℃ incubation for 18-20 hr
  2. Count blue colonies as V. parahaemolyticus

YM ( Yeast and Mold)

• The antibiotics in the medium inhibits the growth of bacteria.
• Most of the yeast presented in blue. Mold is black and cotton-like.
• Steps:
• 1. 20 ~ 25 ℃ incubation for 3 ~ 7 days
  2. Count blue or white colonies as yeast and black cotton-like colonies as mold.

X-BC (Bacillus cereus)

• Other bacteria will not grow on the medium except Bacillus cereus.
• The colonies of Bacillus cereus will be green or blue.
• Steps:
• 1. Incubate in 35 ± 2 ℃ for 24± 2 hr
  2. Count the green or blue colonies as Bacillus cereus.

PA (Pseudomonas aeruginosa)

• The antibiotics in the medium inhibits the growth of bacteria.
• Most of the yeast presented in blue. Mold is black and cotton-like.
• Steps:
• 1. 34 ~ 36 ℃ incubation for 45 ~ 51 hours
  2. Count blue or white colonies as yeast and black cotton-like colonies as mold.

Microbes’ Incubation Medium and Reagents