Dey-Engley Neutralizing Broth is used in disinfectant testing where the neutralization of the antiseptics and disinfectants is important for determining its bactericidal activity. The broth consists of tryptone that provides nitrogen and carbon sources, 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. Sodium bisulfite neutralizes aldehydes; sodium thioglycolate neutralizes mercurial; 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. Those organisms that ferment dextrose will turn the medium from purple to yellow. Growth of Pseudomonas sp., which does not ferment dextrose, can be detected by the formation of a pellicle on the surface of the broth.

Dey-Engley neutralizing broth has been used to premoisten the sponge swab samples[1] to neutralise the residual action of the disinfectants on the microbiological growth.[2] Dey-Engley Neutralizing Broth is used in disinfectant testing where neutralization of the antiseptics and disinfectants for determining bactericidal activity. It has also been used to resuspend the Vermamoeba (Hartmannella) vermiformis cysts to neutralize peracetic acid (PAA).[3]

Dey-Engley Neutralizing Broth is used in disinfectant testing where neutralization of the antiseptics and disinfectants is important for determining bactericidal activity.

The Dey-Engley Neutralizing Broth neutralizes a broad spectrum of antiseptics and disinfectants including, quaternary ammonium compounds, phenolics, iodine, chlorine, mercurials, formaldehyde and glutaraldehyde. Sodium thioglycollate, sodium thiosulphate, sodium bisulphite, soya lecithin and polysorbate 80 act as neutralizing components. Growth is indicated by a color change from purple to yellow.

Ingredients(g/L)
Casein enzymatic hydrolysate5.00
Yeast extract2.50
Dextrose10.00
Sodium thiosulfate6.00
Sodium thioglycollate1.00
Sodium bisulfite2.50
Lecithin7.00
Polysorbate 805.00
Bromocresol purple0.02

Suspend 39 g of Dey-Engley Neutralizing Broth in 1000 ml of distilled water. Boil to dissolve the medium completely. Sterilize by autoclaving 15 lbs. pressure (121°C) for 15 minutes.

We offer two media types: the superior granulated GranuCult^® and the cost-efficient powdered NutriSelect^® culture media, depending on your needs.
The designations basic, plus, or prime are added to indicate the quality control level, from basic quality control to standard QC plus to prime for full regulatory compliance.

GRANUCULT is a registered trademark of Merck KGaA, Darmstadt, Germany

NutriSelect is a registered trademark of Merck KGaA, Darmstadt, Germany