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《AOAC 17.3.10 AOAC Of fi cial Method 2003.01》由會員上傳分享，免費在線閱讀，更多相關內容在行業(yè)資料-天天文庫。
1、17.3.10(f)Sterilesodiumhydroxidesolution.—1M.Dissolve40gAOACOfficialMethod2003.01NaOHinwateranddiluteto1Lwater.Autoclave15minat121°C.EnumerationofEnterobacteriaceae(g)Blender.—High-speed(16000–18000rpm)withsterilejar.inSelectedFoods(h)Incubator.—Maintaining37°±1°C.Petrifilm?Enterobacteriacea
2、eCountPlateMethod(i)Balance.—2000±0.1gcapacity.FirstAction2003FinalAction2006C.SamplePreparation(ApplicabletoenumerationofEnterobacteriaceaeorganismsinAsepticallyweigh11.0gunthawedtestportionintoblenderjar,cheddarcheese,milk,flour,frozenpreparedmeals,frozenbroccoli,B(g).Add99mLdilutionwater,
3、B(e),andblendatandnutpieces.)16000–18000rpmfor2mintohomogenize.IfentiretestsampleisSeeTables2003.01Aand2003.01Bfortheresultsofthe<50g,weighportionoftestsampleandadddilutionwatertomakeinterlaboratorystudysupportingacceptanceofthemethod.1:10dilution.AdjustpHofdilutedtestportionto6.5–7.5with1MN
4、aOH,B(f),ca0.1mL/gtestportion.DonotusediluentscontainingA.Principlecitrate,bisulfite,orthiosulfateastheycaninhibitgrowth.PrepareallMethodusesbacterialcultureplatesofdrymediumwithpHdecimaldilutionswith90mLdilutionwaterplus10mLfromindicatorandcold-water-solublegel.Undilutedordilutedtestpreviou
5、sdilution.Mixalldilutionsbyshaking25timesthroughportionsareaddedtoplatesat1.0mLperplate.Pressureappliedto30cmarcin7s.plasticspreaderplacedonoverlayfilmspreadsthetestportionevenlyover20cm2growtharea.Gellingagentisallowedtosolidify,D.Analysisandplatesareincubatedfor24±2hat37°±1°Candthencounted
6、.PlacedryPetrifilmEBplate,B(a),onflatsurface.Lifttopfilmandinoculate1mLtestsuspensionontocenteroffilmbase.B.ApparatusandReagentsCarefullyrolltopfilmdownontoinoculum.Distributetestportion(a)PetrifilmEnterobacteriaceae(EB)CountPlates.—Plates,over20cm2growthareawithdownwardpressureoncenterofava
7、ilablefrom3MMicrobiologyProducts(3MCenter,St.Paul,MNplasticspreaderdevice,B(b),flatsidedown.Leaveplate55144,USA),containvioletredbileglucose(VRBG)nutrients,pHundisturbedforminimumof1mintopermitgeltosolidify.Incubateindicator,cold-water-solublegelli
