1、Designation: E640 06 (Reapproved 2012)Standard Test Method forPreservatives in Water-Containing Cosmetics1This standard is issued under the fixed designation E640; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the suit-ability of preservatives for use in cosmetic formulations. It setsminim
3、al requirements for preservative performance in modelformulations.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It i
4、s theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E1054 Test Methods for Evaluation of Inactivators of An-timicrobial Agents3. Summa
5、ry of Method3.1 This test method involves a microbiological challengetest of preservatives incorporated into model formulations atrecommended efficacy levels. Routine microbiological proce-dures are used to determine the antimicrobial activity ofpreservatives in formulations. This method requires th
6、e knowl-edge of standard microbiological techniques.4. Significance4.1 This test method should be used to determine if apreservative or preservative system has application for thepreservation of water-miscible cosmetic products.5. Materials5.1 Test FormulationsFormulations that the submitterfeels ar
7、e appropriate for demonstration of preservative activityshall be included in the test. Non-preserved (control) samplesof these formulas shall also be included. Incompatibility of thepreservative(s) with any of the formulations or formulationcomponents shall be noted.5.2 Test Microorganisms (Suggeste
8、d Panel):5.2.1 Other test microorganisms or equivalent species maybe included as appropriate and if standardized cultures fromcosmetic isolates become available. The primary function ofthese cultures is to provide a common basis for comparison ofdifferent preservatives.5.2.1.1 Pseudomonas aeruginosa
9、 ATCC 9027.5.2.1.2 Burkolderia cepacia ATCC 25416.5.2.1.3 Escherichia coli ATTC 8739.5.2.1.4 Staphylococcus aureus ATCC 6538.5.2.1.5 Candida albicans ATCC 10231.5.2.1.6 Enterobacter gergoviae ATCC 33028.5.2.1.7 Aspergillus niger ATCC 16404.5.2.1.8 Eupenicillium levitum ATCC 10464.5.2.2 If available,
10、 cosmetic spoilage microorganisms and/ormicroorganisms obtained from the cosmetic manufacturingenvironment may be used in addition to those microorganismssuggested in 5.2.5.3 Culture MaintenanceThe microorganisms listed in5.2.1 shall be maintained as specified by ATCC.5.3.1 Plating DiluentsPlating d
11、iluents are used to dis-perse the test sample in preparation for plating and, if neces-sary, aid in neutralizing the preservative present to permit theoptimum recovery of surviving microorganisms. The choice ofdiluents is dependent of the diluents ability to meet theneutralization requirements speci
12、fied in 5.3.3. The followingsuggested diluents have been found to be suitable for thispurpose:5.3.1.1 Buffered 1 % Peptone in physiological saline(0.85 % NaCl).5.3.1.2 Dey/Engley (D-E) neutralizing broth.5.3.1.3 Eugon Broth.5.3.1.4 Letheen Broth.5.3.1.5 Modified Letheen Broth.5.3.1.6 Nutrient Broth.
13、5.3.1.7 Phosphate Buffer (pH 7.0).5.3.1.8 TAT Broth.5.3.1.9 Trypticase Soy Broth.1This test method is under the jurisdiction of ASTM Committee E35 onPesticides, Antimicrobials, and Alternative Control Agents and is the directresponsibility of Subcommittee E35.15 on Antimicrobial Agents.Current editi
14、on approved April 1, 2012. Published June 2012. Originallyapproved in 1978. Last previous edition approved in 2006 as E640 06. DOI:10.1520/E0640-06R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStan
15、dards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3.2 Recovery MediaA recovery medium should provideadequate nutritional support for the growth
16、 of the selected testmicroorganisms. The following suggested agar recovery mediahave been found to be suitable for this purpose:5.3.2.1 For Bacteria:Eugon AgarLetheen AgarMicrobial Content AgarModified Latheen AgarPlate Count AgarTrypticase Soy Agar5.3.2.2 For Fungi:Malt AgarMalt Agar ExtractMycophi
17、l AgarPotato Dextrose Agar5.3.3 Preservative NeutralizationNeutralizing agents areincorporated into the plating diluent or the recovery medium,or both, in order to inactivate the preservatives and permit amore accurate enumeration of the microbial content. Whereneutralizers are not available or are
18、ineffective, physicaldilution or membrane filtration may be necessary. (See TestMethods E1054.)6. Procedures6.1 Preparation of Challenge InoculaGrow bacterial cul-tures at 35 6 2C for 24 to 28 h on slants of the appropriatesolid media. Grow yeast cultures on the appropriate media at25 6 2C for 48 to
19、 72 h. Grow mold cultures on theappropriate media at 25 6 2C for 5 to 7 days or until fullsporulation is achieved.6.1.1 Harvesting Bacterial CulturesUsing a sterile inocu-lating loop, transfer the growth from each culture into tubes ofsterile saline. Alternatively, wash culture from slant usingsteri
20、le saline and transfer to a sterile tube. Adjust to yield asuspension of approximately 1 3 108 cfu/mL using a McFar-land Barium Sulfate Standard #2, turbidimetry, optical density,or other technique that correlates to an aerobic plate count.Confirm culture standardization using a verified aerobic bac
21、-terial plate count.6.1.2 Harvesting Yeast CulturesHarvest yeast cultures asdescribed in 6.1.1, however, adjust suspension to approxi-mately 1 3 107cfu/mL. Confirm culture standardization usinga verified aerobic fungal plate count technique.6.1.3 Harvesting MoldHarvest mold spores by addingsterile s
22、aline containing 0.05 % Polysorbate 80 to the cultureand rubbing the growth gently with a sterile inoculating loop orother appropriate sterile implement. Filter through sterilegauze, sterile glass wool, or sterile nonabsorbent cotton.Adjustthe mold spore suspension to approximately 1 3 107cfu/mLusin
23、g a hemocytometer or other reproducible direct micro-scopic counting technique. Confirm culture standardizationusing a verified aerobic fungal plate count. Harvested moldspore cultures may be used immediately or stored at 2 to 5Cfor up to four weeks.6.1.4 Preparation of Inocula:6.1.4.1 Mixed Culture
24、 Method:(1) Mixed BacteriaMix equal portions of selected bac-teria and label “Bacteria 1.”(2) Optional Mixed Bacteria PoolsMix separate bacteriapools for gram-positive bacteria, gram-negative fermenterbacteria, and gram-negative non-fermenter bacteria. Pooledcultures may be used immediately or store
25、d at 2 to 5C for upto 72 hours.(3) Fungi (Mold and Yeast)Mix equal parts of fungalsuspensions thoroughly and label “Fungi #2.”6.1.4.2 Pure Culture MethodOptionally, challenges mayalso be performed using single (pure) cultures. If this methodis chosen, prepare the cultures used for challenges as desc
26、ribedin 6.1 and use directly as described in 6.3. Label sample jarsappropriately according to the test microorganisms used tochallenge that sample.6.1.5 Determination of Challenge Inocula LevelsPre pareserial dilutions of the challenge inocula (6.1.4.1). Plate out induplicate using Letheen agar. Inc
27、ubate bacteria and yeast at32C for 24 h and fungi at 25C for 72 h. Determine thenumber of colony-forming units (cfu) in each inoculum.6.2 Sample PreparationWeigh out 20 g aliquots of thetest material into suitable glass containers and label appropri-ately. Cap and store at ambient temperature (20 to
28、 25C).6.3 Challenge of Test FormulationInoculate each 20 galiquot of the test material by adding 0.2 mL of the appropriateinoculum. Mix thoroughly by shaking, stirring, vortexing, orusing a any other suitable mechanical mixing device. Storeinoculated samples at ambient temperature (20 to 25C).6.4 Mi
29、crobiological Testing:6.4.1 Mix inoculated sample thoroughly. Prepare a 1:10dilution (1 part test material plus 9 parts neutralizing diluent)and mix thoroughly. Additional serial 10-fold dilutions may beprepared as required. Plate diluted test samples in duplicate onthe appropriate selected recovery
30、 agars for bacteria and fungi.6.4.1.1 Invert bacterial plates and incubate at 35 6 2C for48 to 72 hours. Count colonies on plates. Bacterial counts inthe range of 25 to 250 cfu are considered acceptable. Verify theidentity of the microorganisms by gram staining where appro-priate.6.4.1.2 Invert fung
31、al plates and incubate at 25 6 2C for 3to 5 days. Count colonies on plates. Fungal counts in the rangeof 8 to 80 cfu are considered acceptable.6.4.1.3 Where no plates fall into the acceptable countableranges, count the colonies on plate(s) nearest that range.Average the duplicate plate counts and re
32、cord as cfu/g of testmaterial.6.4.2 Test Time IntervalsTest inoculated samples at theminimal suggested test intervals of 0, 7, 14, 21 (optional), and28 days (additional test intervals may be selected as desired).6.5 RechallengeIf the preservative is intended for cosmet-ics that are subject to repeat
33、ed insult by the consumer, the useof a rechallenge procedure may be considered. Rechallenge thetest aliquots at 21 or 28 days and continue the test another 28days, thereby repeating all procedures described for the initialchallenge.7. Interpretation of Data7.1 The following may be used as the criter
34、ia for demon-strating the effectiveness of a preservative incorporated into themodel cosmetic systems:E640 06 (2012)27.1.1 Bacteria and yeast should show at least a 99.9 % (3log) reduction within seven days following each challenge andno increase thereafter for the remainder of the test withinnormal
35、 variation of the data.7.1.2 Fungi should show at least a 90 % (1 log) reductionwithin seven days following each challenge and no increasethereafter for the remainder of the test within normal variationof the data.7.2 Calculate the percent (%) reduction as follows:% Reduction = Inoculum Count Sample
36、 Count 3 100Inoculum Count7.3 The uninoculated test material must contain less than100 cfu/g to proceed with the challenge test.7.4 Inoculum counts must be in the prescribed ranges or thetest is considered to be invalid and must be repeated.7.5 If preservative neutralization is not demonstrated, the
37、test is invalid and cannot be repeated until a suitable neutral-izing agent or procedure is developed.8. Precision and Bias8.1 The precision and bias of this method have not beendetermined. Replicate samples are recommended.9. Keywords9.1 bacterial; cosmetics; microbial challenge; preservativeperfor
38、mance criteria; preservativesASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof inf
39、ringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this stand
40、ard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your vi
41、ews known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).E640 06 (2012)3
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