Coliform testing

Coliform bacteria are indicator organisms used to assess sanitary quality and potential contamination in raw materials and finished products.

Tests We Offer

• Coliform Test — USP <61>/<2021>

 Test Methodology

USP <61> Methodology (Microbial Enumeration Tests)

Under USP <61>, coliform testing is performed using a selective culture-based enumeration approach designed to recover and quantify indicator organisms.

• Sample is prepared and homogenized to ensure representative distribution

• Serial dilution is performed where required

• Inoculation onto selective and differential agar media

• Incubation under controlled temperature conditions

• Detection of lactose-fermenting colonies based on characteristic color change or gas production

• Enumeration of colonies to estimate microbial load

This method is primarily used for quantitative microbial limit testing (MLT) and supports compliance with pharmacopeial acceptance criteria.

USP <2021> Methodology (Microbial Examination of Non-Sterile Products)

Under USP <2021>, coliform testing is performed as part of a broader microbial examination framework for non-sterile products, with enhanced focus on recovery and confirmation of indicator organisms.

• Sample preparation with emphasis on neutralization of preservatives or inhibitory substances

• Use of selective enrichment media to promote recovery of stressed organisms

• Incubation under defined conditions to encourage growth of coliform bacteria

• Isolation on selective/differential media for Gram-negative lactose fermenters

• Confirmatory biochemical testing (e.g., oxidase-negative confirmation and lactose fermentation profile)

• Optional confirmatory identification for regulatory reporting

This approach is designed to ensure higher recovery accuracy in complex pharmaceutical and dietary supplement matrices.

Why it Matters

• Ensures sanitary quality of raw materials and finished products

• Detects contamination from water, handling, or processing failures

• Supports compliance with USP <61> and USP <2021> requirements

• Strengthens GMP and quality assurance programs

• Provides reliable microbial quality indicators for regulatory audits

How to Connect

Reach out to Unicorn Analytical Services for coliform detection and testing.