Cat. no. K107 Buffered Peptone Water, 16x125mm Tube, 9ml 20 tubes/box
Cat. no. K195 Buffered Peptone Water, 16x125mm Tube, 10ml 20 tubes/box
Cat. no. U142 Buffered Peptone Water, 500ml Polycarbonate Bottle,
10 bottles/box
Cat. no. U143 Buffered Peptone Water, 500ml Polycarbonate Bottle,
10 bottles/box
Cat. no. D080 Buffered Peptone Water, Dilu-Lok II™ Vial, 90ml 50 vials/case
Cat. no. D089 Buffered Peptone Water, Dilu-Lok II™ Vial, 99ml 50 vials/case


Hardy Diagnostics Buffered Peptone Water is intended to aid in the recovery of injured Salmonella species from foods and other samples prior to selective enrichment and isolation.

This product is not intended to be used for the diagnosis of human disease.


Salmonella spp. that may be present in a food product can be sublethally injured by food processing techniques. These injured Salmonella spp. may not be recovered by direct selection techniques. Buffered Peptone Water is a non-selective preenrichment broth that promotes the recovery of those bacteria that may be injured.

Peptone in the media supplies nitrogenous compounds needed for the growth of bacteria. The phosphate salts provide buffering capacity to maintain the pH. Maintenance of the pH is important when attempting to recover injured bacteria, because a low pH can be detrimental to the repair of the damaged cells.


Ingredients per liter of deionized water.*

Peptone 10.0gm
Sodium Chloride 5.0gm
Disodium Phosphate 3.5gm
Monopotassium Phosphate 1.5gm

Final pH 7.2 +/- 0.2 at 25 ºC.

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


Storage: Upon receipt store at 2-30ºC away from direct light. Media should not be used if there are any signs of contamination, deterioration, discoloration, or if the expiration date has passed. Product is light and temperature sensitive. Protect from freezing.



For the isolation of Salmonella spp.: (1,3)

1. Inoculate 50ml Buffered Peptone Water by adding 10gm of sample.

2. Incubate at 35ºC. for 18 hours.

3. Transfer 10ml of the incubated sample to 100ml of Tetrathionate Broth (Cat. no. K65) and incubate at 35ºC. Other selective enrichments may be used. (1,3)

4. After 24 and 48 hours, subculture to Brilliant Green Agar (Cat. no. G75), XLD Agar (Cat. no. G65) and/or HE Agar (Cat. no. G65) and incubate the plates for 18 hours at 35ºC. No one selective agar media is ideal in all situations. This justifies the use of two or more agar media. (1,3)

5. Examine plates for typical Salmonella spp. colonies.

Please consult listed references for complete procedures for the uses of Buffered Peptone Water, and for the recovery of Salmonella spp. (1-5)


Following incubation, examine the agar plates for growth and typical colony morphology.

Refer to the Hardy Diagnostics software program, HUGO™, for more information on the uses and interpretations of Tetrathionate Broth, XLD Agar, Brilliant Green Agar, HE Agar and others used in this method.


Competing flora in the test sample can affect the recovery and may overgrow Salmonellae.


Standard microbiological supplies and equipment such as loops, other culture media, swabs, applicator sticks, incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.


Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Products K107, K195, U142, and U143:
Salmonella enterica
ATCC ® 14028
A 18-24hr 35°C Aerobic Growth and typical colony morphology upon subculture to XLD Agar
Escherichia coli
ATCC ® 25922
A 18-24hr 35°C Aerobic Partial to complete inhibition upon subculture to XLD Agar
Products D080 and D089:
Salmonella enterica
ATCC ® 14028
A 18-24hr 35°C Aerobic Growth and typical colony morphology upon subculture to XLD Agar

User Quality Control


Buffered Peptone Water should appear clear and colorless to straw.


1. U.S. Food and Drug Administration. Bacteriological Analytical Manual. Arlington, VA. http://www.fda.gov/Food/FoodScienceResearch/LaboratoryMethods/ucm2006949.htm

2. American Public Health Association. Standard Methods for the Examination of Dairy Products, APHA, Washington, D.C.

3. APHA Technical Committee on Microbiological Methods for Foods. Compendium of Methods for the Microbiological Examination of Foods, APHA, Washington, D.C.

4. Sadovski, A.Y. 1977. J. Food Technology ; 12:85-91.

5. Juven, B.J., N. Cox, J.S. Bailey, J.E. Thomson, O.W. Charles, and J.V. Schutze. 1984. Recovery of Salmonella from artificially contaminated poultry feeds in non-selective and selective broth media. Jour. of Food Prot. ; 47:299-302.

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