ASTM E640-06(2019)

Standard Test Method for Preservatives in Water-Containing Cosmetics

SIGNIFICANCE AND USE
4.1 This test method should be used to determine if a preservative or preservative system has application for the preservation of water-miscible cosmetic products.
SCOPE
1.1 This test method covers the determination of the suitability of preservatives for use in cosmetic formulations. It sets minimal requirements for preservative performance in model formulations.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Dec-2018
• ICS: 71.100.70 - Cosmetics. Toiletries
• Technical Committee: E35 - Pesticides, Antimicrobials, and Alternative Control Agents
• Drafting Committee: E35.15 - Antimicrobial Agents

Relations

• Replaces: ASTM E640-06(2012) - Standard Test Method for Preservatives in Water-Containing Cosmetics
• Effective Date: 01-Jan-2019
• Refers: ASTM E1054-08 - Standard Test Methods for Evaluation of Inactivators of Antimicrobial Agents
• Effective Date: 01-Apr-2008
• Refers: ASTM E1054-02 - Standard Test Methods for Evaluation of Inactivators of Antimicrobial Agents
• Effective Date: 10-May-2002
• Referred By: ASTM E723-13(2019) - Standard Practice for Evaluation of Antimicrobials as Preservatives for Aqueous-Based Products Used in the Paper Industry (Bacterial Spoilage)
• Effective Date: 01-Jan-2019
• Referred By: ASTM D4783-01(2021) - Standard Test Methods for Resistance of Adhesive Preparations in Container to Attack by Bacteria, Yeast, and Fungi
• Effective Date: 01-Jan-2019

Overview

ASTM E640-06(2019), Standard Test Method for Preservatives in Water-Containing Cosmetics, establishes a scientific framework for assessing the effectiveness of preservative systems in water-miscible cosmetic formulations. The method ensures minimal requirements for preservative performance are met, enhancing product safety and quality. Developed by ASTM International in alignment with the World Trade Organization (WTO) Technical Barriers to Trade (TBT) Committee principles, this standard guides cosmetic manufacturers on evaluating and validating antimicrobial protection in their products.

Key Topics

• Preservative Performance Testing: Provides standard procedures for testing the efficacy of preservatives or preservative systems in water-based cosmetics through microbiological challenge tests.
• Testing Microorganisms: Involves specific bacterial and fungal strains relevant to cosmetic spoilage and contamination, such as Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, Aspergillus niger, and others.
• Sample Preparation and Inoculation: Outlines methodologies for preparing and inoculating model cosmetic formulations to mimic real-world contamination scenarios.
• Microbial Enumeration: Describes procedures for counting surviving microorganisms using validated microbiological techniques.
• Neutralization and Growth Recovery: Details the incorporation of neutralizing agents and appropriate culture media to ensure accurate assessment of preservative efficacy.
• Reduction Criteria:
  • Bacteria and yeast: Minimum 99.9% (3-log) reduction within 7 days.
  • Fungi: Minimum 90% (1-log) reduction within 7 days.
• Safety and Regulatory Compliance: Stresses the responsibility of users to establish appropriate safety, health, and environmental safeguards and evaluate relevant regulatory requirements.

Applications

ASTM E640 is widely applicable across the cosmetics industry for:

• Product Development: Assists formulators in selecting suitable preservative systems during the creation of new water-containing cosmetic products such as lotions, creams, shampoos, and gels.
• Quality Control: Supports routine quality assurance processes by providing standardized procedures to test preservative efficacy consistently.
• Regulatory Compliance: Facilitates compliance with global regulations that require documented evidence of preservation against microbial contamination in cosmetic products.
• Comparative Assessment: Offers a common framework for comparing different preservatives or preservation strategies, aiding in optimal product formulation decisions.
• Risk Management: Reduces the risk of microbial spoilage, thereby safeguarding consumer health and preserving the reputation of cosmetic brands.

Related Standards

To ensure comprehensive preservation and microbial safety in cosmetic products, the following standards are commonly referenced alongside ASTM E640:

• ASTM E1054 - Test Methods for Evaluation of Inactivators of Antimicrobial Agents
• ISO 11930 - Cosmetics - Microbiology - Evaluation of the antimicrobial protection of a cosmetic product
• USP <51> - Antimicrobial Effectiveness Testing

These standards contribute to a holistic approach in evaluating antimicrobial agents in personal care and cosmetic products.

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Keywords: preservatives, water-containing cosmetics, antimicrobial efficacy, microbial challenge test, cosmetic formulation, ASTM standards, quality control, safety, regulatory compliance.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E640 − 06 (Reapproved 2019)
Standard Test Method for
Preservatives in Water-Containing Cosmetics
This standard is issued under the fixed designation E640; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Significance
1.1 This test method covers the determination of the suit- 4.1 This test method should be used to determine if a
abilityofpreservativesforuseincosmeticformulations.Itsets preservative or preservative system has application for the
preservation of water-miscible cosmetic products.
minimal requirements for preservative performance in model
formulations.
5. Materials
1.2 The values stated in SI units are to be regarded as
5.1 Test Formulations—Formulations that the submitter
standard. No other units of measurement are included in this
feels are appropriate for demonstration of preservative activity
standard.
shall be included in the test. Non-preserved (control) samples
1.3 This standard does not purport to address all of the
of these formulas shall also be included. Incompatibility of the
safety concerns, if any, associated with its use. It is the
preservative(s) with any of the formulations or formulation
responsibility of the user of this standard to establish appro-
components shall be noted.
priate safety, health, and environmental practices and deter-
5.2 Test Microorganisms (Suggested Panel):
mine the applicability of regulatory limitations prior to use.
5.2.1 Other test microorganisms or equivalent species may
1.4 This international standard was developed in accor-
be included as appropriate and if standardized cultures from
dance with internationally recognized principles on standard-
cosmetic isolates become available. The primary function of
ization established in the Decision on Principles for the
these cultures is to provide a common basis for comparison of
Development of International Standards, Guides and Recom-
different preservatives.
mendations issued by the World Trade Organization Technical
5.2.1.1 Pseudomonas aeruginosa ATCC 9027.
Barriers to Trade (TBT) Committee.
5.2.1.2 Burkolderia cepacia ATCC 25416.
5.2.1.3 Escherichia coli ATTC 8739.
2. Referenced Documents
5.2.1.4 Staphylococcus aureus ATCC 6538.
2.1 ASTM Standards:
5.2.1.5 Candida albicans ATCC 10231.
E1054Test Methods for Evaluation of Inactivators of Anti-
5.2.1.6 Enterobacter gergoviae ATCC 33028.
microbial Agents
5.2.1.7 Aspergillus niger ATCC 16404.
5.2.1.8 Eupenicillium levitum ATCC 10464.
3. Summary of Method
5.2.2 If available, cosmetic spoilage microorganisms and/or
3.1 This test method involves a microbiological challenge
microorganisms obtained from the cosmetic manufacturing
test of preservatives incorporated into model formulations at
environment may be used in addition to those microorganisms
recommended efficacy levels. Routine microbiological proce-
suggested in 5.2.
dures are used to determine the antimicrobial activity of
5.3 Culture Maintenance—The microorganisms listed in
preservativesinformulations.Thismethodrequirestheknowl-
5.2.1 shall be maintained as specified by ATCC.
edge of standard microbiological techniques.
5.3.1 PlatingDiluents—Platingdiluentsareusedtodisperse
the test sample in preparation for plating and, if necessary, aid
in neutralizing the preservative present to permit the optimum
This test method is under the jurisdiction of ASTM Committee E35 on
recovery of surviving microorganisms. The choice of diluents
Pesticides, Antimicrobials, and Alternative Control Agentsand is the direct respon-
is dependent of the diluents ability to meet the neutralization
sibility of Subcommittee E35.15 on Antimicrobial Agents.
requirements specified in 5.3.3. The following suggested di-
Current edition approved Jan. 1, 2019. Published January 2019. Originally
luents have been found to be suitable for this purpose:
approvedin1978.Lastpreviouseditionapprovedin2012asE640–06(2012).DOI:
10.1520/E0640-06R19.
5.3.1.1 Buffered 1% Peptone in physiological saline
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
(0.85% NaCl).
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
5.3.1.2 Dey/Engley (D-E) neutralizing broth.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 5.3.1.3 Eugon Broth.
Copyright ©ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959. United States
E640 − 06 (2019)
5.3.1.4 Letheen Broth. using a verified aerobic fungal plate count. Harvested mold
5.3.1.5 Modified Letheen Broth. spore cultures may be used immediately or stored at 2 to 5°C
for up to four weeks.
5.3.1.6 Nutrient Broth.
6.1.4 Preparation of Inocula:
5.3.1.7 Phosphate Buffer (pH 7.0).
6.1.4.1 Mixed Culture Method:
5.3.1.8 TAT Broth.
(1)Mixed Bacteria—Mix equal portions of selected bacte-
5.3.1.9 Trypticase Soy Broth.
ria and label “Bacteria 1.”
5.3.2 Recovery Media—Arecovery medium should provide
(2)Optional Mixed Bacteria Pools—Mix separate bacteria
adequate nutritional support for the growth of the selected test
pools for gram-positive bacteria, gram-negative fermenter
microorganisms.Thefollowingsuggestedagarrecoverymedia
bacteria, and gram-negative non-fermenter bacteria. Pooled
have been found to be suitable for this purpose:
cultures may be used immediately or stored at 2 to 5°C for up
5.3.2.1 For Bacteria:
to 72 hours.
EugonAgar
LetheenAgar (3)Fungi (Mold and Yeast)—Mix equal parts of fungal
Microbial ContentAgar
suspensions thoroughly and label “Fungi #2.”
Modified LatheenAgar
6.1.4.2 Pure Culture Method—Optionally, challenges may
Plate CountAgar
Trypticase SoyAgar
also be performed using single (pure) cultures. If this method
ischosen,preparetheculturesusedforchallengesasdescribed
in 6.1 and use directly as described in 6.3. Label sample jars
5.3.2.2 For Fungi:
appropriately according to the test microorganisms used to
MaltAgar
challenge that sample.
MaltAgar Extract
6.1.5 Determination of Challenge Inocula Levels—Pre pare
MycophilAgar
Potato DextroseAgar
serial dilutions of the challenge inocula (6.1.4.1). Plate out in
duplicate using Letheen agar. Incubate bacteria and yeast at
5.3.3 Preservative Neutralization—
...