Buffered Peptone Water M614
Intended use
Buffered Peptone Water is a pre-enrichment medium used for increasing the recovery of injured Salmonella species from
foods prior to selective enrichment and isolation.
Composition**
Ingredients Gms / Litre
Proteose peptone 10.000
Sodium chloride 5.000
Disodium phosphate, anhydrous 3.500
Monopotassium phosphate 1.500
Final pH ( at 25°C) 7.2±0.2
**Formula adjusted, standardized to suit performance parameters
Directions
Suspend 20.00 grams in 1000 ml distilled water. Heat if necessary to dissolve the medium completely.Sterilize by
autoclaving at 15 lbs pressure (121°C) for 15 minutes. If desired, aseptically add rehydrated contents of 1 vial of EC O157 :
H7 Selective Supplement (FD247) for isolation of Escherichia coli O157 from foods to previously molten and cooled to
45-50°C medium . Mix well and dispense ino sterile tubes or flasks as desired.
Principle And Interpretation
Buffered Peptone Water is a pre-enrichment medium designed to help recovery of sub-lethally damaged Salmonellae before
transfer to a selective medium. This pre-enrichment medium is free from inhibitors and is well buffered and provides conditions
for resuscitation of the cells that have been injured by processes of food preservation. It was noted by Edel and Kampelmacher
(1) that sub-lethal injury to Salmonella may occur due to food preservation techniques involving heat, desiccation, high
osmotic pressure, preservatives or pH changes. Buffered Peptone Water during the pre-enrichment period helps in recovery
of injured cells that may be sensitive to low pH (2). This is particularly important for vegetable specimens, which have low
buffering capacity. This medium can be used for testing dry poultry feed (3). In a survey involving isolation of Salmonellae
from meat that had been artificially contaminated with sub-lethally injured organisms, pre-enrichment in Buffered Peptone
Water at 37°C for 18 hours before selection in Tetrathionate Brilliant Green Bile Broth (M1255) showed superior results
compared with direct selection method. Lactose Broth is frequently used as a pre-enrichment medium but it may be detrimental
to recovery of Salmonellae (4).
The media contain proteose peptone as a source of carbon, nitrogen, vitamins and minerals. Sodium chloride maintains the
osmotic balance and phosphates buffer the medium. The broth is rich in nutrients and produces high resuscitation rates for
sublethally injured bacteria and supports intense growth. The phosphate buffer system prevents bacterial damage due to changes
in the pH of the medium.
Inoculate 10 grams specimen in 50 ml of these media and incubate at 35-37°C for 18 hours. Transfer 10 ml from this medium
to 100 ml of Tetrathionate Broth (M032) and incubate at 43°C for 24 - 48 hours and then subculture on selective plating media.
Examine the plates for characteristic Salmonella colonies.
Type of specimen
Food and dairy samples
Specimen Collection and Handling:
For food and dairy samples, follow appropriate techniques for sample collection and processing as per guidelines (5,6,7).
After use, contaminated materials must be sterilized by autoclaving before discarding.
Warning and Precautions :
Read the label before opening the container. Wear protective gloves/protective clothing/eye protection/ face protection.
Follow good microbiological lab practices while handling specimens and culture. Standard precautions as per
established guidleines should be followed while handling specimens. Safety guidelines may be referred in individual
Please refer disclaimer Overleaf.
HiMedia Laboratories Technical Data
safety data sheets
Limitations :
Due to nutitional variations some strains may show poor growth.
Performance and Evaluation
Performance of the medium is expected when used as per the direction on the label within the expiry period when stored at
recommended temperature.
Quality Control
Appearance
Cream to yellow homogeneous free flowing powder
Colour and Clarity of prepared medium
Light yellow coloured, clear solution without any precipitate
Reaction
Reaction of 2.0% w/v aqueous solution at 25°C. pH : 7.2±0.2
pH
7.00-7.40
Cultural Response
Cultural characteristics observed after an incubation at 35-37°C for 18-24 hours.(Recovery is carried out using XLD
Agar, M031).
Organism Inoculum Growth Recovery
(CFU)
Salmonella Enteritidis ATCC 50-100 good-luxuriant >=50%
13076 (00030*)
Salmonella Typhi ATCC 50-100 good-luxuriant >=50%
6539
Salmonella Typhimurium 50-100 good-luxuriant >=50%
ATCC 14028 (00031*)
Escherichia coli 0157:H7 50-100 good-luxuriant >=50%
NCTC 12900 (00014*) [Recovery on
Tryptone soya
Agar(M290)]
Key : *Corresponding WDCM numbers.
Storage and Shelf Life
Store between 10-30°C in a tightly closed container and the prepared medium at 15-25°C. Use before expiry date on
the label. On opening, product should be properly stored dry, after tightly capping the bottle inorder to prevent lump
formation due to the hygroscopic nature of the product. Improper storage of the product may lead to lump formation.
Store in dry ventilated area protected from extremes of temperature and sources of ignition Seal the container tightly
after use. Use before expiry date on the label.
Product performance is best if used within stated expiry period.
Disposal
User must ensure safe disposal by autoclaving and/or incineration of used or unusable preparations of this product. Follow
established laboratory procedures in disposing of infectious materials and material that comes into contact with clinical
sample must be decontaminated and disposed of in accordance with current laboratory techniques (8,9).
Reference
1. Edel and Kampelmacher, 1973, Bull. W.H.O., 48:167.
2. Sadovski, 1977, J. Food Technol., 12:85.
3. Juven, Cox, Bailey, Thomson, Charles and Schutze, 1984, J. Food Prot., 47:299.
4. Angelotti, 1963, Academic Press, New York, N.Y.
5. American Public Health Association, Standard Methods for the Examination of Dairy Products, 1978, 14th Ed., Washington
D.C.
6. Salfinger Y., and Tortorello M.L. Fifth (Ed.), 2015, Compendium of Methods for the Microbiological Examination of
Foods, 5th Ed., American Public Health Association, Washington, D.C.
Please refer disclaimer Overleaf.
HiMedia Laboratories Technical Data
7. Wehr H. M. and Frank J. H., 2004, Standard Methods for the Microbiological Examination of Dairy Products, 17th Ed.,
APHA Inc., Washington, D.C.
8. Isenberg, H.D. Clinical Microbiology Procedures Handb0ook. 2nd Edition.
9. Jorgensen,J.H., Pfaller , M.A., Carroll, K.C., Funke, G., Landry, M.L., Richter, S.S and Warnock., D.W. (2015)
Manual of Clinical Microbiology, 11th Edition. Vol. 1.
Revision : 04/2018
Disclaimer :
User must ensure suitability of the product(s) in their application prior to use. Products conform solely to the information contained in
this and other related HiMedia™ publications. The information contained in this publication is based on our research and development
work and is to the best of our knowledge true and accurate. HiMedia™ Laboratories Pvt Ltd reserves the right to make changes to
specifications and information related to the products at any time. Products are not intended for human or animal or therapeutic use but
for laboratory,diagnostic, research or further manufacturing use only, unless otherwise specified. Statements contained herein should not
be considered as a warranty of any kind, expressed or implied, and no liability is accepted for infringement of any patents.
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