Designation:E2800−11StandardPracticeforCharacterizationofBacillusSporeSuspensionsforReferenceMaterials1ThisstandardisissuedunderthefixeddesignationE2800;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.INTRODUCTIONBacillusspp.areaerobic,rod-shaped,Grampositivebacteriathatproduceendosporesundernutrientlimitingconditions.Theendosporesaredesignedtopersistinextremeenvironmentsandconsequentlyarehighlyresistanttoinactivationbyheat,chemicalsandirradiation.AfewspeciesofBacillusaremedicallyimportantbecauseoftheirimpactonhumanandanimalhealthwhileothershaveimportantagriculturalandindustrialapplications.MeasurementofviableBacillussporespresentinasuspensioncanbeperformedusingclassicalmicrobiologytechniques,suchasgrowthonnutrientmedium.Thesporesuspensionisdiluted,analiquotspreadonsolidnutrientmedium,incubatedatanappropriatetemperature,andtheresultingcoloniescounted.TheselectionofthetypeofgrowthmediumandincubationtemperaturefortheoptimalgrowthofaparticularBacillusspeciesshouldbedeterminedbyconsultationofrelevantliteratureorbycomparisonofdifferentgrowthmediaandincubationtemperatures.Bacillussporereferencematerialshavemanyimportantapplicationsinagriculture,basicresearch,medicaldiagnosis,detectorvalidation,andsterilitytesting.Uniformmethodsforthecharacterizationofsporeswillimprovethecomparisonofdifferentlotsofmaterialsandresultsbetweendifferentlaboratories.1.Scope1.1ThispracticeisfocusedontwobasicmeasurementstocharacterizeBacillusreferencematerials,theenumerationofsporesusinggrowthofcoloniesonnutrientmediaandusingphasecontrastmicroscopytodeterminesporequalityandhomogeneity.AdditionalinformationonadvancedmethodsforcharacterizationisprovidedinAppendixX1.1.2Thisdocumentwillprovidetheuserwithrecommenda-tionsformeasurementmethods,andthedetailsandconditionsthatshouldbeemployedtoens...
