1、Designation:D819618Standard Practice forDetermination of Water Activity(aw)in Cannabis Flower1This standard is issued under the fixed designation D8196;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A numbe
2、r 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 equatebacterial growth potential with water content
3、.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 thatawis more closely related to the microbial,chemic
4、al,and physical properties of foods and othernatural products than is total moisture.3It is firmly established that growth of specific microbes isinhibited at or below specific water activity values.4Total water content(moisture)measurements do not necessarily reflect water available for microbialgr
5、owth 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 measurementis more accurate than total water content(moisture)measurement as it relates directly to the wateravail
6、able to microbes.Safe awlevels are constant relative to particular microbes,regardless of thesubstance being tested.1.Scope1.1 This practice covers the recommended procedure fordetermining the water activity(aw)of a cannabis flowersample.1.2 UnitsThe values stated in SI units are to be regardedas th
7、e standard.Water activity is a ratio,and thus is withoutunit designation.1.3 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.1.4 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-me
9、ndations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:5D8197 Specification for Maintaining Acceptable Water Ac-tivity(aw)Range(0.55 to 0.65)for Dry Cannabis Flower3.Terminology3.1 Definitions of Terms Specific to This Standa
10、rd:3.1.1 cannabis flower,nthe flowering or fruiting tops ofthe cannabis plant(excluding seeds and leaves when notaccompanied by flowering or fruiting top)from which the resinhas not been extracted.(adapted from the UN Single Conven-tion on Narcotic Drugs,19616)3.1.2 cultivator container,npackaging u
11、sed by cannabisgrower/harvester to store and/or ship product in large quantitiesafter drying.3.1.3 dispensary container,npackaging used by acannabis-dispensing establishment to provide the cannabisflower consumer a satisfactory storage container.1This practice is under the jurisdiction of ASTM Commi
12、ttee D37 on Cannabisand is the direct responsibility of Subcommittee D37.04 on Processing andHandling.Current edition approved May 15,2018.Published May 2018.DOI:10.1520/D8196-18.2Scott,W.J.,Water relations of Staphylococcus aureus at 30.Australian Journalof Biological Sciences6,1953,pp 549-564.3Chi
13、rife,J.and Fontana,A.J.(2007)Introduction:Historical Highlights ofWater Activity 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.
14、,and Gould,G.W.Solutes and Low Water Activity inFood Preservatives ed N.J.Russell and G.W.Gould,Springer 2012,pp119ff.5For 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
15、 standards Document Summary page onthe ASTM website.6www.unodc.org/pdf/convention_1961_en.pdf,p1,Accessed 2018.01.23Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally
16、 recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 3.1.4 packager container,npackaging used by the pack-ager to store and ship product to dispensing establishments.3.1.5 water activity,aw,nthe partial vapor pressure ofwater in a substance divided by the partial vapor pressure ofpure water at the same temperatu
