Dey-Engley Neutralizing Broth is supplied by HiMedia. It is a sterile ready prepared media containing 5ml of purple to reddish purple clear solution in bottles. Dey-Engley Neutralizing Broth, is generally used in disinfectant testing where neutralization of the antiseptics and disinfectants is important for determining its bactericidal activity. It is advisable to store this ready prepared media between 2-8C. Composition (in gm/L) is as follows:

Tryptone (5.00)

Yeast extract (2.50)

Dextrose (10.00)

Sodium thioglycollate (1.00)

Sodium thiosulphate (6.00)

Sodium bisulphite (2.50)

Lecithin (7.00)

Polysorbate 80 (5.00)

Bromocresol purple (0.02)

Dey-Engley Neutralizing Broth is formulated as per the procedure described by Engley and Dey. The Dey-Engley Neutralizing Broth neutralizes a broad spectrum of antiseptics and disinfectants including quaternary ammonium compounds, phenolics, iodine and chlorine preparations, mercurials, formaldehyde and glutaraldehyde. Tryptone provides nitrogen and carbon source, long chain amino acids, vitamins and other essential nutrients. Dextrose is an energy source. Yeast extract is also a rich source of vitamin B-complex. The present formulation integrates neutralizing substances for almost all the active products used as antiseptics and disinfectants. Sodium bisulfite neutralizes aldehydes; sodium thioglycollate neutralizes mercurials; sodium thiosulfate neutralizes iodine and chlorine; lecithin neutralizes quaternary ammonium compounds; and polysorbate 80, a non-ionic surface-active agent, neutralizes substituted phenolics. Bromocresol purple is an indicator for dextrose utilization.