Buffered Peptone Water (BPW), 500g

Buffered Peptone Water (BPW) is used for the non-selective pre-enrichment of Salmonella spp. from food and is not intended for use in the diagnosis of disease or other conditions in humans. Edel and Kamelmacher found that food preservation techniques involving heat, desiccation, preservatives, high osmotic pressure, or pH changes cause sublethal injury to Salmonella spp. Preenrichment in a non-selective medium allows for the repair of cell damage and facilitates the recovery of Salmonella. Lactose Broth is frequently used for this purpose, but it may be detrimental to recovering Salmonellae. Buffered Peptone Water maintains a high pH over the pre-enrichment period and allows for the repair of injured cells that may be sensitive to low pH. This is particularly important for vegetable specimens, which have a low buffering capacity. Buffered Peptone Water is used in standard methods.

Typical Formulation

Formula Litre
Enzymatic Digest of Casein 10.0 g/L
Sodium Chloride 5.0 g/L
Disodium Hydrogen Phosphate (anhydrous) 3.5 g/L
Potassium Dihydrogen Phosphate 1.5 g/L

Preparation

Dissolve 20 g of the medium in one litre of purified water.
Mix thoroughly.
Autoclave at 121°C for 15 minutes.