D/E Neutralizing Agar

D/E Neutralizing Agar is used for the isolation of microorganisms from sanitized environmental surfaces in a laboratory setting. D/E Neutralizing Agar is not intended for use in the diagnosis of disease or other conditions in humans.

D/E Neutralizing Agar was developed by Dey and Engley to neutralize a broad spectrum of disinfectants and preservative antimicrobial chemicals, including quaternary ammonium compounds, phenolics, iodine, chlorine preparations, mercurials, formaldehyde, and glutaraldehyde. D/E Neutralizing media neutralize higher concentrations of residual antimicrobials when compared with other standard neutralizing formulations, such as Letheen media, Thioglycollate media, and Neutralizing Buffer.

Total neutralization of disinfectants is critical. Disinfectant residues can result in a false negative (no-growth) test. D/E Neutralizing Agar effectively neutralize the inhibitory action of disinfectant carryover, allowing differentiation between bacteriostasis and true bactericidal action of disinfectant chemicals. This is a critical characteristic to consider when evaluating a disinfectant. D/E Neutralizing Agar is recommended for use in disinfectant evaluations, environmental sampling (swab and contact plate methods), and testing of water-miscible cosmetics.


Formula Liter
Enzymatic Digest of Casein 5 g
Yeast Extract 2.5
Dextrose 10 g
Sodium Thioglycollate 1 g
Sodium Thiosulfate 6 g
Sodium Bisulfite 2.5 g
Polysorbate 80 5 g
Lecithin (Soybean) 7 g
Bromscresol Purple 0.02 g
Agar 15 g

Final pH: 7.6 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.


  1. Suspend 54 g of the medium in one liter of purified water.
  2. Heat with frequent agitation and boil for one minute to completely dissolve the medium.
  3. Autoclave at 121°C for 15 minutes.

Order Details

Product # Product Description
7375A D/E Neutralizing Agar, 500 g
7375T D/E Neutralizing Agar, 5 kg