1、Designation: D8197 18Standard Specification forMaintaining Acceptable Water Activity (aw) Range (0.55 to0.65) for Dry Cannabis Flower1This standard is issued under the fixed designation D8197; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONThe concept of water activity is more than 50 years old. For many years, researchers tried to eq
3、uatebacterial growth potential with water content. William Jones Scott showed in 1953 that microorgan-isms have a limiting awlevel for growth,2thus being the first to establish that bacterial growthcorrelated with water activity, not water content of organic materials. It is now generally accepted t
4、hatawis more closely related to the microbial, chemical, and physical properties of foods and othernatural products than is total moisture.3It is firmly established that growth of specific microbes andmetabolism of microbe associated toxins are inhibited at or below specific water activity values.4,
5、5Total water content (moisture) measurements do not necessarily reflect water available for microbialgrowth and thus are an inaccurate means for controlling microbial growth, because the water contentsufficient for microbial growth is dependent on the substance being tested. Water activity measureme
6、ntis more accurate than total water content measurement as it relates directly to the water available (inliquid form) to microbes and is constant relative to the particular microbe, regardless of the substancebeing tested.1. Scope1.1 This specification covers the recommended range of awsuitable for
7、safe and efficacious storage of cannabis flowers orportions thereof.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and
8、 deter-mine the applicability of regulatory limitations prior to use.1.3 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-m
9、endations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:6D8196 Practice for Determination of Water Activity (aw)inCannabis Flower3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 water activity, aw,nth
10、e partial vapor pressure ofwater in a substance divided by the partial vapor pressure ofpure water at the same temperature which is calculated bydividing the partial vapor pressure of water in the substance (P)by the partial vapor pressure of pure water at the sametemperature (Po), i.e., aw= P/(Po).
11、 This describes quantita-tively the capability of the cannabis flower in a sealed containerto affect the humidity of the containers headspace air.1This specification is under the jurisdiction of ASTM Committee D37 onCannabis and is the direct responsibility of Subcommittee D37.04 on Processing andHa
12、ndling.Current edition approved May 15, 2018. Published May 2018. DOI: 10.1520/D8197-182Scott, W.J., Water relations of Staphylococcus aureus at 30. Australian Journalof Biological Sciences6, 1953, pp 549-564.3Chirife, J. and Fontana, A. J. (2007) Introduction: Historical Highlights ofWater Activity
13、 Research, in Water Activity in Foods: Fundamentals and Applica-tions (eds G. V. Barbosa-Cnovas, A. J. Fontana, S. J. Schmidt and T. P. Labuza),Blackwell Publishing Ltd, Oxford, UK. doi: 10.1002/9780470376454.ch14Russell, N.J., Leistner, L., and Gould, G.W. Solutes and Low Water Activity inFood Pres
14、ervatives ed N.J. Russell and G.W. Gould, Springer 2012, pp119ff.5Naresh Magan, David Aldred, Post-harvest control strategies: Minimizingmycotoxins in the food chain, International Journal of Food Microbiology, Volume119, Issues 12, 2007, Pages 131-139, ISSN 0168-1605, https:/doi.org/10.1016/j.ijfoo
15、dmicro.2007.07.034.6For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Har
16、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendat
17、ions issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.14. Significance and Use4.1 This specification is designed for use on cannabis flowerby cannabis producers, processors, dispensers, testinglaboratories, and end users.4.2 Analysis and control of water activity sh
18、ould be consid-ered an important quality control step in ensuring a cannabisflower sample is being stored under optimal storage conditionsto prevent mold or other microbiological growth and breakage.4.3 All constituent testing, other than water activity perPractice D8196, shall be carried out on the
19、 cannabis flowersample that has been equilibrated to this specification per 6.1and 6.2.4.4 Maintaining the requisite awthroughout the supplychain from completion of drying through merchandising en-sures safety and quality for the consumer.4.5 Water activity (aw) is often used as a critical controlpo
20、int of Hazard Analysis and Critical Control Points (HACCP)programs. Controlling awshould not be seen as a kill step.7Rather control of awfocuses on preventing the growth andproliferation of microorganisms.5. Testing5.1 Refer to Practice D8196.6. Chemical CompositionSpecification for StoringCannabis
21、Flower6.1 awshall be less than 0.65 to ensure against undesirablegrowth of microorganisms such as mold.6.2 awshall be greater than 0.55 to ensure against physicaldamage (breakage) in routine handling and storage.7. Special Considerations7.1 awvalues shall be between 0.55 and 0.65.7.2 If awis greater
22、 than 0.68, further drying of the cannabisflower(s) shall be required to ensure the awis 0.55 to 0.65.7.3 If awis less than 0.68, co-storage with a salt-based aw(relative humidity) control sachet(s) designed to maintain therelative humidity between 0.55 to 0.65 can effectively bring thestored cannab
23、is flower(s) into the specified 0.55 to 0.65 awrange.7.4 Storing cannabis flower with appropriately designed aw(relative humidity) salt-based control sachets designed tomaintain a relative humidity of 0.55 to 0.65 in sealed contain-ers can maintain the optimum storage conditions.8. Keywords8.1 aw; c
24、annabis; cannabis flower; mold; physical damage;water activity; water contentREFERENCES(1) “Fungus in Medical Marijuana Eyed as Possible Cause in CaliforniaMans Death,” http:/ (accessed 2017/09/03).(2) Chirife, J. and Fontana, A. J. (2007) Introduction: Historical High-lights of Water Activity Resea
25、rch, in Water Activity in Foods:Fundamentals and Applications (eds G. V. Barbosa-Cnovas, A. J.Fontana, S. J. Schmidt and T. P. Labuza), Blackwell Publishing Ltd,Oxford, UK. doi: 10.1002/9780470376454.ch1(3) Holmes, M., Vyas, J. M., Steinbach, W., and McPartland, J., andreferences therein, “Microbiol
26、ogical Safety Testing of Cannabis,”Cannabis Safety Institute, May 2015.(4) Ledward, D.A., “Water activity: Theory and applications to food (IFTBasic Symposium 85 Series),” Louis B. Rockland and Larry R.Beuchat, Eds., Meat Sci., Vol 21, 1987, pp. 157-86 158.(5) Pitt, J.I., Xerophillic fungi and the s
27、poilage of foods of plant origin. InWater Relations of Foods, R.B. Duckworth Ed. 1975, pp 273-307.Academic Press, New York.(6) Scott, W.J., Water relations of Staphylococcus aureus at 30. Austra-lian Journal of Biological Sciences6, 1953, pp 549-564.(7) Troller, J. A., “Trends in research related to
28、 the influence of “wateractivity” on microorganisms in food,” Adv. Exp. Med. Biol., Vol 302,1991, pp. 305-313.ASTM 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
29、 that determination of the validity of any such patent rights, and the riskof infringement 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 rea
30、pproved or withdrawn. Your comments are invited either for revision of this standard 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 yo
31、u feel that your comments have not received a fair hearing you shouldmake your views 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
32、 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 t
33、he Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ “kill step” is the term typically used to describe a point in the foodmanufacturing process where potentially deadly pathogens are eradicated from theproduct (usually by killing the pathogen). Traditionally the “kill step” has involvedcooking, pasteurization, pathogen-killing washes, irradiation, etc. Accessed 2/16/2018.D8197 182
