CRITERION™ NUTRIENT GELATIN

Cat. no. C6480 CRITERION™ Nutrient Gelatin 256gm
Cat. no. C6481 CRITERION™ Nutrient Gelatin 500gm
Cat. no. C6482 CRITERION™ Nutrient Gelatin 2kg
Cat. no. C6483 CRITERION™ Nutrient Gelatin 10kg
Cat. no. C6484 CRITERION™ Nutrient Gelatin 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ Nutrient Gelatin is used to aid in classification of the Enterobacteriaceae by determining an organism's ability to liquify gelatin.

This dehydrated culture medium is a raw material intended to be used in the making of prepared media products, which will require further processing, additional ingredients, or supplements.

SUMMARY

Gelatin was the substance originally used to gel culture media. However, gelatin is liquid at 35ºC., the optimum temperature for many bacteria. In addition, some bacteria are capable of liquifying the gelatin, making it an unsuitable solidifying agent. Agar, gelatin's replacement, has neither of these drawbacks.

The breakdown of gelatin is a result of the production of the enzyme gelatinase by an organism. The purpose of this proteolytic enzyme is to break down large molecules so that they can be brought into the cell to be metabolized. This ability to liquify gelatin is characteristic of certain Enterobacteriaceae such as Proteus species and Serratia species.

Nutrient Gelatin contains peptone and beef extract as carbon and nitrogen sources for general growth requirements. Gelatin is the Substrate for determining of the microorganism has the proteolytic enzyme to hydrolyze (liquify) the gelatin.

FORMULA

Gram weight per liter: 128.0gm/L
Gelatin 120.0gm
Peptone 5.0gm
Beef Extract 3.0gm

Final pH 6.8 +/- 0.2 at 25ºC

* Adjusted and/or supplemented as required to meet performance criteria.

STORAGE AND SHELF LIFE

Store the sealed bottle(s) containing dehydrated culture medium at 2-30ºC. Dehydrated culture medium is very hygroscopic. Keep lid tightly sealed. Protect dehydrated culture media from moisture and light. The dehydrated culture media should be discarded if it is not free-flowing or if the color has changed from its original tan.

Store the prepared culture media at 2-8ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

1. Suspend 128.0gm of the dehydrated culture media in 1 liter of distilled or deionized water.

2. Warm to 50-55ºC. to dissolve completely.

3. Dispense required amount in test tubes and place caps on tubes.

4. Sterilize in the autoclave at 121ºC. for 15 minutes.

PROCEDURE AND INTERPRETATION OF RESULTS

For information on procedures and interpretation of results, refer to the prepared media Instructions for Use (IFU) for Cat. No. Q23.

LIMITATIONS

A control tube must be run in parallel with each test. One control tube can be used for all organisms being tested, if all tubes are inoculated at the same time.(2)

If the tubes are incubated at temperatures of greater than 20 degrees C., the tubes must be chilled below 20 degrees C before reactions can be determined.(2)

Do not shake the tubes after incubation, as some positive liquifaction reactions will be missed.(2)

Fastidious bacteria may not grow in Nutrient Gelatin.

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as autoclaves, incinerators, and incubators, etc., are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Staphylococcus aureus
ATCC ® 25923
D up to 14 days 35°C Aerobic Growth; positive liquifaction
Clostridium perfringens
ATCC ® 13124
D up to 14 days 35°C Aerobic Growth; positive liquifaction
Bacillus subtilis
ATCC ® 6633
D up to 14 days 35°C Aerobic Growth; positive liquifaction
Escherichia coli
ATCC ® 25922
D up to 14 days 35°C Aerobic Growth; negative liquifaction

User Quality Control

PHYSICAL APPEARANCE

CRITERION™ Nutrient Gelatin powder should appear homogeneous, free-flowing, and tan in color. The prepared media should appear clear and colorless.

REFERENCES

1. Baron, E.J., L.R. Peterson and S.M. Finegold. 1994. Bailey & Scott's Diagnostic Microbiology, 10th ed. Mosby, St. Louis, MO.

2. MacFaddin, J.F. 1985. Media for Isolation, Cultivation, Identification, Maintenance of Bacteria, Vol. I. Williams & Wilkins, Baltimore, MD.

3. Howard, B.J., et al. 1997. Clinical and Pathogenic Microbiology. 2nd ed. Mosby, St. Louis, MO.

4. Isenberg, H.D. Clinical Microbiology Procedures Handbook, Vol. I, II & III. American Society for Microbiology, Washington, D.C.


ATCC is a registered trademark of the American Type Culture Collection.

061416gr