Cat. no. C6630 CRITERION™ Presence-Absence Broth 183gm
Cat. no. C6631 CRITERION™ Presence-Absence Broth 500gm
Cat. no. C6632 CRITERION™ Presence-Absence Broth 2kg
Cat. no. C6633 CRITERION™ Presence-Absence Broth 10kg
Cat. no. C6634 CRITERION™ Presence-Absence Broth 50kg


Hardy Diagnostics CRITERION™ Presence-Absence Broth, also known as P-A Broth, is used for detecting coliforms in treated water.

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.


The Presence-Absence Broth test presumptively detects for coliforms in water. The test is a simple modification of the multiple-tube procedure.(4) One test sample, 100ml, is inoculated into a single culture bottle to obtain qualitative information on the presence or absence of coliforms based on the presence or absence of lactose fermentation.(4) This test is based on the principle that coliforms and other pollution indicator organisms should not be present in a 100ml water sample.(5-10)

Comparative studies with the membrane filter procedure indicate the Presence-Absence test may maximize coliform detection in samples containing many organisms that could overgrow coliform colonies and cause problems in detection.(4) The Presence-Absence test is described in standard methods for water testing and by US EPA.(10)


Gram weight per liter (Single strength): 30.5gm/L
Lactose 7.46gm
Pancreatic Digest of Gelatin 5.0gm
Pancreatic Digest of Casein 4.92gm
Peptic Digest of Animal Tissue 4.91gm
Beef Extract 3.0gm
Sodium Chloride 2.46gm
Dipotassium Phosphate 1.35gm
Monopotassium Phosphate 1.35gm
Sodium Lauryl Sulfate 0.05gm
Bromcresol Purple 8.5mg

Final pH 6.8 +/- .02 at 25ºC.

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


Store the sealed bottle 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 beige.



1. Suspend the following desired amounts of the dehydrated culture media in 1 liter of distilled or deionized water:

Single strength: 30.5gm/L
Double strength: 61.0gm/L
Triple strength: 91.5gm/L

2. Warm gently to dissolve completely.

3. Dispense 50ml amount into screw cap 250ml milk dilution bottles.

4. Autoclave at 121ºC. for 12 minutes, with the total autoclave time not to exceed 30 minutes.

5. Cool to room temperature.


For information on procedures and interpretation of results, consult listed references.


Since the nutritional requirements of organisms vary, some strains may be encountered that fail to grow or grow poorly on this medium.

The Presence-Absence test is only a presumptive test for coliforms.

Confirmation and differentiation of coliforms detected by the Presence-Absence test may be achieved by use of appropriate confirmatory media, incubation times and temperatures as outlined in appropriate references.

Extending the Presence-Absence test incubation period to 72 or 96 hours will allow isolation of other indicator organisms. However, indicator bacteria isolated after 48 hours incubation may not be considered for regulatory purposes.


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


Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Escherichia coli
ATCC ® 25922
A 18-48hr 35°C Aerobic Good growth; yellow color with or without gas production
Enterococcus faecalis
ATCC ® 29212
B 18-48hr 35°C Aerobic Moderate growth; slight yellow to purple color change
Pseudomonas aeruginosa
ATCC ® 27853
B 18-48hr 35°C Aerobic Poor to moderate growth; no color change

User Quality Control


CRITERION™ Presence-Absence Broth powder should appear homogeneous, free-flowing, and beige in color. The prepared media should appear clear, slightly opalescent, and purple in color without significant precipitate.


1. Jorgensen., et al. Manual of Clinical Microbiology, American Society for Microbiology, Washington, D.C.

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

3. Eaton, A.D., et al. 1995. Standard Methods for the Examination of Water and Wastewater, American Public Health Association, 19th ed. Washington, D.C.

4. Weiss, J.E. and C.A. Hunter. 1939. Simplified bacteriological examination of water. J. Am. Water Works Assoc.; 31:707-713.

5. Clark, J.A. 1968. The detection of various bacteria indicative of water pollution by a presence-absence procedure. Can. J. Microbiol.; 14:13-18.

6. Clark, J.A. and L.T. Vlassoff. 1973. Relationships among pollution indicator bacteria isolated from raw water and distribution systems by the presence-absence test. Health Lab. Sci.; 10:163-172.

7. Clark, J.A. 1977. Pollution indicator bacteria associated with municipal raw and drinking water supplies. Can. J. Microbiol.; 26:827-832.

8. Clark, J.A. 1980. The influence of increasing numbers of non-indicator organisms upon the detection of indicator organisms by the membrane filter and presence-absence tests. Can. J. Microbiol.; 26:827-832.

9. Clark, J.A., et al. 1982. Characterization of indicator bacteria in municipal raw water, drinking water and new main water samples. Can. J. Microbiol.; 28:1002-1013.

10. Federal Register. 1989. National primary drinking water regulations: total coliforms (including fecal coliforms and E. coli). Fed. Regist.; 54:27544-27568.

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