NEUTRALIZING BROTH WITHOUT INDICATOR
CAT Nº: 2082
For the neutralization of chemical antimicrobial products
in environmental samples and in surfaces of sanitary interest
FORMULA IN g/l
Dextrose
10.00
Yeast Extract
2.50
Lecithin
7.00
Sodium Bisulfite
2.50
Sodium Thiosulfate
6.00
Sodium Thioglycollate
1.00
Casein Peptone
5.00
Polysorbate 80
5.00
Final pH 7.6 ± 0.2 at 25ºC
PREPARATION
Suspend 39 grams of the medium in one liter of distilled water. Mix well and dissolve by heating with frequent agitation.
Boil for one minute until complete dissolution. Dispense into appropriate containers and sterilize in autoclave at 121°C
for 15 minutes. The prepared medium should be stored at 2-8°C. The color is amber, slightly opalescent.
The dehydrated medium should be homogeneous, free-flowing and beige in color. If there are any physical changes,
discard the medium.
USES
NEUTRALIZING BROTH WITHOUT INDICATOR without indicator is used to neutralize a broad spectrum of disinfectants
and preservative antimicrobial chemicals.
If the sample contains any disinfectant or preservative, microorganisms won’t growth, obtaining a false negative result.
Casein peptone provides nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is the source of
vitamins, particularly of the B-group. Dextrose is the fermentable carbohydrate providing carbon and energy. Lecithin
neutralizes Quaternary Ammonium Compounds (QACs), parahydroxybenzoates (parabens) and bis-biguanides. Sodium
thiosulfate neutralizes mercurial, halogens and aldehydes. Sodium bisulfite neutralizes glutaraldehyde and mercurial and
polysorbate 80 QACs, iodide and parabens.
Prepare the medium as indicated above and prepare the medium according the procedure that is used in each case.
MICROBIOLOGICAL TEST
The following results were obtained in the performance of the medium from type cultures after incubation at a
temperature of 35  2C and observed after 40-48 hours.
Microorganisms
Growth
Escherichia coli ATCC 25922
Good
Bacillus subtilis ATCC 6633
Good
Pseudomonas aeruginosa ATCC 27853
Good
Staphylococcus aureus ATCC 25923
Good
Salmonella typhimurium ATCC 14028
Good
BIBLIOGRAPHY
1
LABORATORIOS CONDA, S.A.
www.condalab.com
Engley, F. B., Jr. and B. P. Dey. 1970. A universal neutralizing medium for antimicrobial chemicals. Presented at the Chemical
Specialties Manufacturing Association (CSMA) Proceedings. 56th Mid-Year Meeting.
Eur Pharma. Edition 8th
STORAGE
25ºC
Once opened keep powdered medium closed to avoid hydration.
2ºC
2
LABORATORIOS CONDA, S.A.
www.condalab.com