Preservative Efficacy Test (PET) Laboratory India | Cosmetic Microbiology | NABL

Auriga Research provides NABL-accredited preservative efficacy testing (PET) and cosmetic microbiology services for skincare, haircare, colour cosmetics, and personal care products. Challenge testing confirms that a product's preservative system can prevent microbial proliferation throughout its intended shelf life — a critical safety and quality requirement.

Our PET programme follows ISO 11930, USP 51, and European Pharmacopoeia EP 5.1.3 protocols. Products are challenged with standardised inocula of bacteria (S. aureus, P. aeruginosa, E. coli), yeast (C. albicans), and mould (A. brasiliensis). Log reductions are measured at days 7, 14, and 28 to classify preservative adequacy.

We also provide complete microbial limit testing including total aerobic count, yeast and mould count, and absence testing for specified pathogens per ISO 17516. These tests are required for BIS certification, CDSCO registration, and export compliance.

Testing Capabilities

Preservative efficacy test (PET) per ISO 11930
Challenge testing per USP 51 and EP 5.1.3
Total aerobic microbial count (TAMC)
Total yeast and mould count (TYMC)
Absence testing: S. aureus, P. aeruginosa, E. coli, C. albicans
Water activity (aw) measurement
In-use microbial contamination testing
Environmental monitoring for manufacturing facilities
Rapid microbial detection (ATP bioluminescence)

Turnaround Time

Standard PET per ISO 11930 takes approximately 5 weeks (28-day challenge plus reporting). Microbial limit testing takes 5-7 business days. Rapid screening methods provide preliminary results in 7-14 days.

Related Services

Frequently Asked Questions

What is a preservative efficacy test (PET)?

A preservative efficacy test, also called challenge testing, evaluates whether a cosmetic formulation can adequately control microbial growth throughout its shelf life. The product is inoculated with specified concentrations of bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli), yeast (Candida albicans), and mould (Aspergillus brasiliensis). Microbial counts are measured at defined intervals (7, 14, 28 days) to assess the log reduction achieved by the preservative system.

What standards apply to cosmetic preservative efficacy testing?

ISO 11930 is the primary international standard for cosmetic PET. USP 51 (used in North America) and European Pharmacopoeia EP 5.1.3 provide alternative criteria. ISO 11930 classifies results as A (adequate protection) or B (minimum protection). The pass criteria require specific log reductions at each time point. Products failing PET require reformulation of the preservative system before market launch.

How long does preservative efficacy testing take?

Standard PET per ISO 11930 takes 28 days for the inoculation phase plus 5-7 days for reporting, totalling approximately 5 weeks. Rapid PET methods using ATP bioluminescence can provide preliminary results in 7-14 days. Microbial limit testing (total count, specified pathogens) takes 5-7 business days.