Quantitative Culture Testing
Culture-Based Enumeration Methods
Measure viable microbial populations with culture-based counts selected for the product, organism group, reference method, and specification.
Results are generally reported as colony-forming units per gram or milliliter. The applicable limit is defined by the product category, processing history, intended use, target market, and customer or compendial specification—not by a single universal microbial limit. The standard sample quantity is 2 g.
Enumeration Methods
Quantitative culture methods in one service family
Each entry names the reference pathway shown in Cora Science's current accreditation scope. The laboratory confirms the exact revision, matrix application, specification, and report before testing.
USP <61> and USP <2021>
Total Aerobic Plate Count
Estimates viable aerobic microorganisms recovered under the selected method conditions. The result may also be described as a total aerobic microbial count in the applicable reference context.
Technique: Plate count
USP <61> and USP <2021>
Total Yeast and Mold Count
Quantifies recoverable yeasts and molds under the selected incubation and media conditions. Product form and processing can materially affect the appropriate specification.
Technique: Plate count
AOAC 991.14
Escherichia coli and Total Coliforms
Provides quantitative indicator results for generic E. coli and total coliforms. A generic E. coli result does not identify a pathogenic strain.
Technique: Plate count with selective/colorimetric media
AOAC 2003.01
Total Enterobacteriaceae
Provides an Enterobacteriaceae count when that indicator is required by a customer specification or documented product rationale. It is not a universal substitute for more specific organism testing.
Technique: Plate count with selective/colorimetric media
AOAC 2003.07
Staphylococcus aureus Enumeration
Quantifies S. aureus recovered under the selected method conditions. The result and any included confirmation should be interpreted against the defined product specification.
Technique: Plate count with selective/colorimetric media
Other culture-based enumeration methods or organisms may be available by request. Availability and accreditation status are confirmed for the exact method and matrix.
Reporting And Specifications
Define the count, unit, and decision together
A result is useful only when its method, reporting unit, range, specification, and decision rule match the submitted product.
Quantitative result
Counts are generally reported in CFU/g for solid materials or CFU/mL for liquids, with method-specific qualifiers and reporting limits where applicable.
Specification comparison
Cora Science can report against a supplied customer specification or review an applicable USP, AHPA, or other reference framework before testing.
Interpretation boundary
An enumeration result describes organisms recovered under the selected conditions. It does not by itself establish pathogen absence, product safety, or regulatory compliance.
AHPA Botanical Guidance
Reference limits vary by botanical material type
These values summarize selected examples from AHPA's current guidance. They support specification review; they are not automatic limits for every ingredient, food, supplement, or cosmetic.
On a narrow screen, scroll horizontally to review both material categories.
| Microbial parameter | Dried, non-extracted herbs | Powdered or soft herbal extracts |
|---|---|---|
| Total aerobic plate count | ≤ 10⁷ CFU/g | ≤ 10⁴ CFU/g |
| Total yeasts and molds | ≤ 10⁵ CFU/g | ≤ 10³ CFU/g |
| Total coliforms | ≤ 10⁴ CFU/g | ≤ 10² CFU/g |
| Generic Escherichia coli | Not detected, < 3 MPN/g, or < 10 CFU/g | Not detected, < 3 MPN/g, or < 10 CFU/g |
| Staphylococcus aureus | ≤ 10⁴ CFU/g | ≤ 10⁴ CFU/g |
AHPA distinguishes indicator organisms from pathogens and states that its guidance may not apply to every herbal ingredient or supplement. Product form, other ingredients, excipients, intended use, processing, and hazard analysis can change which tests and limits are appropriate.
AHPA notes that total coliforms are a historical indicator and that more precise methods may be available. It discourages Enterobacteriaceae as a general indicator unless a product-specific reason supports that choice.
Analytical variability and the applicable decision rule must be written into the specification rather than assumed from a displayed target value.
Eligible Matrix Families
Confirm method fit within the scoped product family
The accreditation scope lists broad matrix families. Technical review still determines whether a specific formulation and preparation are suitable for the selected method.
Materials and ingredients
Raw materials, extracts, and dietary ingredients within the verified method-and-matrix scope.
Foods and beverages
Food and beverage matrices after technical review of formulation, processing, and method fit.
Finished products
Dietary supplements and cosmetics when the selected enumeration method is suitable.
Technical Review
Define the product, count, and specification
Share enough context for the laboratory to confirm method fit, reporting, sample needs, and the decision rule before testing begins.
- Exact product, matrix, ingredients, processing, and preservative context
- Requested organism or indicator group and reference method
- Required units, reporting limit or range, and customer or compendial specification
- Applicable decision rule, including treatment of analytical variability
- Standard 2 g sample quantity, sample count, lot or unit sampling plan, and requested deadline
- Target market and any method, report, or accreditation requirement
FAQ
Planning a culture-based enumeration request
Do the AHPA example limits apply to every botanical product?
No. AHPA expressly qualifies its guidance by material type, processing, formulation, intended use, and hazard context. Cora Science can use an applicable reference or a customer-defined specification after technical review.
Does a generic E. coli count identify a pathogenic strain?
No. A generic E. coli indicator result does not determine whether a pathogenic strain is present. Any strain-specific follow-up is a separate testing question.
Are other enumeration methods or organisms available?
Other culture-based enumeration requests may be available by technical review. Provide the organism or group, matrix, reference method, units, range, and specification so availability and accreditation status can be confirmed.
How much sample should I submit?
The standard sample quantity for enumeration is 2 g. Tell the laboratory if less material is available or if the submission combines multiple services so the complete quantity can be confirmed during quoting.
Is confirmation included?
Yes. Every method includes confirmation by a parallel or orthogonal approach, such as different selective or differential media, a biochemical assay, or qPCR, as appropriate to the organism, matrix, and method.
What turnaround is available?
Standard turnaround is 5 business days. Expedited turnaround as fast as 2 days may be available for a fee; confirm feasibility and timing with the laboratory when requesting the quote.
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