Anti Microbial Tests

CHALLENGE TEST (PET- Preservative Efficacy Test):

CHALLENGE TEST (PET- Preservative Efficacy Test):
Challenge test is a procedure in which a product is challenged by exposure to specified types of bacteria and fungi to determine whether it is adequately preserved.
Assessment of preservative efficacy is needed over the intended shelf-life of that product
According to ISO 11930:2012
According to European Pharmacopoeia (Ph. Eur.)
According to United States Pharmacopoeia (USP)
Zone of Inhibition test or Kirby-Bauer Test, is a very common qualitative technique to screen the anti-microbial activity of an ingredient/ formulation. The test can be conducted for bacterial and fungal cultures.
The ZOI can be done by  to measure antibiotic resistance and To test the ability of an ingredient/s to inhibit the microbial growth
Disc Diffusion method
Well diffusion method


Minimum inhibitory concentrations (MICs) are the lowest concentration of an antimicrobial that will inhibit the visible growth of a microorganism.
The lowest concentration of antimicrobial that kills the bacteria.
Maintenance Of Natural Skin Flora
The effect of skin care products on natural skin flora such as S. aureus and S. epidermidis, is tested to check the maintenance of the natural flora.
The skin microbiome samples are collected by buffer scrub / gyratory shaker method
The collected samples are checked for the common skin commensals at baseline and post product application.
The quantification of the commensals is carried out by qPCR method.
This method is useful to check if skin care products cause any depletion of the natural commensals.

Microbiological Tests

Our independent microbiology testing services offer world-class capability across many industries including food, consumer products, cosmetics and beauty products, medical devices, drinking water.

Microbiology testing services are a crucial requirement across many industries worldwide where products, processes and human health are at risk of being negatively affected by the presence and breeding of micro-organisms such as specific pathogens, bacteria, yeast and moulds.

Product Categories


Determining the efficacy of hand sanitizers by comparing the results of the microbial count.

Reference: ASTM E-2755Strains: E. coli, Staphylococcus aureus, Serratia marcescens



Reference: ASTM E-2274, E- 2406

Strains: E.coli, S.aureus, Klebsiella, Pseudomonas aeruginosa

The test can be performed by two methods;

Washing machine wash

Bucket wash

– Inoculation of fabric swatches with various microbial strains and  treatment with the detergent for specific time.

– Analysis of the reduction in microbial count as compared to the untreated fabric swatch (control)


a. Anti-acne cleansers/soaps:

– Anti microbial efficacy of anti acne formulations tested against C.acnes.

– Time kill assay based on ASTM E-2315 or E-2783 guidelines

– Used to study the activity of an antimicrobial agent against a bacterial strain and can determine the bactericidal or bacteriostatic activity of an agent over time.

b. Anti – Dandruff shampoos:

– Efficacy of anti-dandruff shampoos tested against M.furfur.

– Based on time kill assay


Testing the efficacy of  oral care products against;

– Total viable count- both aerobic and anaerobic

– Tongue surface bacteria- Malodor bacteria

– Streptococcus mutans- caries causative agent

– Lactobacilli spp.

– Periodontitis etiological agent- Porphyromonas gingivalis

– Microbial swabs collected using sterile cotton swabs at baseline and at different time points i.e. immediately after brushing , 2 hours, 4 hours, 8 hours and 12 hours after brushing

– Reduction in the microbial count as compared to baseline analyzed.