Pathology Media

Fungal and Bacterial Detection Media
Media Preparation and Storage
Media Composition Table

Media Preparation and Storage

Corn Meal Agar (Product No. C 1176)

Corn meal agar is recommended for the culture of phytopathological fungi and is also recommended for the production of chlamydospores by Candida albicans. The basic steps for preparing this product are listed below:

1. Suspend 17.0 g of powder in 1 liter of distilled water (W 3500) and heat to boiling or until the medium is completely dissolved. Add 1% polyoxyethylenesorbitan monooleate (Tween 80) (Product No. P 4780) to encourage chlamydospore production.
2. Sterilize the medium in a validated autoclave at 1 kg/cm2 (15 psi), 121 °C. The medium should attain a temperature of 121 °C for at least 15 minutes. Refer to the Sterilization of Media Protocol.
3. Dispense the medium as desired.

STORAGE

All medium preparations should be stored at 0-5 °C. Store dry medium at room temperature (below 30 °C). The dehydrated powder should be light yellow, homogeneous and free-flowing. Deterioration of powdered medium may be recognized by: 1) granulation, clumping, or particulate matter throughout the powder; 2) pH change; 3) inability to promote growth when properly used.

Czapek Dox Broth (Product No. C 1551)

Czapek Dox Broth is a defined liquid medium, designed for the cultivation of fungi and bacteria capable of utilizing inorganic nitrogen and is especially useful for the cultivation of various soil bacteria and fungi and many saprophytic aspergilli. This medium is prepared with only inorganic sources of nitrogen (Sodium Nitrate) and a chemically defined carbon source (Glucose). This product is a modification of the Czapek formula of Dox according to Thom and Raper (1945). The basic steps for preparing this product are listed below:

1. Suspend 35.0 g of powder in 1 liter of distilled water and heat to boiling or until the medium is completely dissolved.
2. Sterilize the medium in a validated autoclave at 1 kg/cm2 (15 psi), 121 °C. The medium should attain a temperature of 121 °C for at least 15 minutes. Refer to the Sterilization of Media Protocol.
3. Dispense the medium as desired. The prepared medium may have a slight precipitate.

STORAGE

All medium preparations should be stored at 0-5 °C. Store dry medium at room temperature (below 30 °C). The dehydrated powder should be white, homogeneous and free-flowing. Deterioration of powdered medium may be recognized by: 1) granulation, clumping, or particulate matter throughout the powder; 2) pH change; 3) inability to promote growth when properly used.

Malt Extract Broth (Product No. M 6409)
Malt Extract Agar (Product No. M 6907)

Malt Extract Broth and Agar are used for the isolation and detection of yeasts and molds. The carbohydrates present in these media are well suited to support the growth of many fungi. The basic steps for preparing these products are listed below:

1. Suspend the appropriate amount of powder in 1 liter of distilled/deionized water. Dissolve the agar medium by heating to a boil. Avoid overheating this product as it might result in a softer agar gel and increased darkening of the medium.
2. Sterilize the medium in a validated autoclave at 1 kg/cm2 (15 psi), 121 °C. The medium should attain a temperature of 121 °C for at least 15 minutes. Refer to the Sterilization of Media Protocol.
3. Dispense the medium as desired (before or after autoclaving).

STORAGE

All medium preparations should be stored at 0-5 °C. Store dry medium at room temperature (below 30 °C). The dehydrated powder should be off-white, homogeneous and free-flowing. Deterioration of powdered medium may be recognized by: 1) granulation, clumping, or particulate matter throughout the powder; 2) pH change; 3) inability to promote growth when properly used.

Nutrient Broth (Product No. N 7519)
Nutrient Agar 1.5% (Product No. N 4019)

Sigma Nutrient Broth and Agar 1.5% are general purpose microbiological media for less fastidious organisms. The basic steps for preparing these products are listed below:

1. Suspend the appropriate amount of powder in 1 liter of distilled/deionized water. Dissolve the agar medium by heating to a boil.
2. Sterilize the medium in a validated autoclave at 1 kg/cm2 (15 psi), 121°C. The medium should attain a temperature of 121 °C for at least 15 minutes. Refer to the Sterilization of Media Protocol.
3. Dispense the medium as desired (before or after autoclaving).

STORAGE

All medium preparations should be stored at 0-5 °C. Store dry medium at room temperature (below 30 °C). The dehydrated powder should be light tan, homogeneous and free-flowing. Deterioration of powdered medium may be recognized by: 1) granulation, clumping, or particulate matter throughout the powder; 2) pH change; 3) inability to promote growth when properly used.

Oatmeal Agar (Product No. O 3506)

Sigma Oatmeal Agar is recommended for the cultivation of fungi, particularly for macrospore formation.The basic steps for preparing this product are listed below:

1. Suspend 72.5 g of powder in 1 liter of distilled/deionized water and heat to boiling until the medium is completely dissolved. Agitate the medium to obtain a uniform suspension.
2. Sterilize the medium in a validated autoclave at 1 kg/cm2 (15 psi), 121 °C. The medium should attain a temperature of 121 °C for at least 15 minutes. Refer to the Sterilization of Media Protocol.
3. Dispense the medium as desired. Swirl the medium during dispensing to obtain a uniform mixture.

STORAGE

All medium preparations should be stored at 0-5 °C. Store dry medium at room temperature (below 30 °C). The dehydrated powder should be beige, non-homogeneous and slightly lumpy. The prepared medium will be off-white to opaque with non-homogeneous particles present. Deterioration of powdered medium may be recognized by: 1) granulation, clumping, or particulate matter throughout the powder; 2) pH change; 3) inability to promote growth when properly used.

Potato Dextrose Broth (Product No. P 6685)
Potato Dextrose Agar (Product No. P 2182)

Potato Dextrose Broth and Agar are standard media for culturing bacteria, fungi, yeast and molds. The basic steps for preparing these products are listed below:

1. Suspend the appropriate amount of powder in 1 liter of distilled/deionized water. Dissolve the agar medium by heating to a boil.
2. Sterilize the medium in a validated autoclave at 1 kg/cm2 (15 psi), 121 °C. The medium should attain a temperature of 121 °C for at least 15 minutes. Refer to the Sterilization of Media Protocol.
3. Dispense the medium as desired (before or after autoclaving).

STORAGE

All medium preparations should be stored at 0-5 °C. Store dry medium at room temperature (below 30 °C). The dehydrated powder should be light beige, homogeneous and free-flowing. Deterioration of powdered medium may be recognized by: 1) granulation, clumping, or particulate matter throughout the powder; 2) pH change; 3) inability to promote growth when properly used.

Luria Broth Base, Miller, LB (Product No. L 1900)
Luria Agar Base, Miller, LB (Product No. L 2025)

Luria Broth and Agar are media used for culturing bacteria used in molecular biology studies. The basic steps for preparing these products are listed below:

1. Suspend the appropriate amount of powder in 1 liter of distilled/deionized water. Dissolve the agar medium by heating to a boil.
2. Sterilize the medium in a validated autoclave at 1 kg/cm2 (15 psi), 121 °C. The medium should attain a temperature of 121 °C for at least 15 minutes. Refer to the Sterilization of Media Protocol.
3. Dispense the medium as desired (before or after autoclaving).

STORAGE

All medium preparations should be stored at 0-5 °C. Store dry medium at room temperature (below 30 °C). The dehydrated granules should be light tan, homogeneous and free-flowing. Deterioration of powdered medium may be recognized by: 1) granulation, clumping, or particulate matter throughout the powder; 2) pH change; 3) inability to promote growth when properly used.

Back to Top

Media Composition Table