Ragweed (Ambrosia sp.) seeds in bird feed · Ragweed (Ambrosia sp.) seeds in bird feed 41 500 g,...
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BA SE Biotechnol. Agron. Soc. Environ. 2011 15(S1), 39-44 Ragweed (Ambrosia sp.) seeds in bird feed Geneviève Frick (1) , Heinrich Boschung (1) , Gudrun Schulz-Schroeder (2) , Gabriele Russ (2) , Igor Ujčič-Vrhovnik (3) , Breda Jakovac-Strajn (3) , Daniela Angetter (4) , Ingrid John (4) , Jan Sten Jørgensen (5) (1) Agroscope Liebefeld-Posieux Research Station (ALP). Tioleyre, 4. P.O. Box 64. CH-1725 Posieux (Switzerland). E-mail: [email protected] (2) Chemisches- undVeterinäruntersuchungsamt Rhein-Ruhr-Wupper (CVUA-RRW). Deutscher Ring, 100. D-47798 Krefeld (Germany). (3) University of Ljubljana. Veterinary Faculty. National Veterinary Institute (NVI). Unit for Pathology ofAnimal Nutrition and Environmental Hygiene. Gerbiceva, 60. SLO-1115 Ljubljana (Slovenia). (4) Landeslabor Berlin-Brandenburg (LLBB). Templinerstraße, 21. D-14473 Potsdam (Germany). (5) The Danish Plant Directorate (DPD). Skovbrynet, 20. DK-2800 Lyngby (Denmark). Five years of monitoring and control for ragweed seeds in bird feed done by members of the IAG working group (International Association for Feedingstuff Analysis, Section Feedingstuff Microscopy). In 2005, the Swiss official feed inspection of Agroscope Liebefeld-Posieux Research Station (ALP) was mandated to check bird feed and raw materials for the presence of Ambrosia sp. seeds. Indeed, such seeds were found in varying amounts when analyzed in the feed microscopy laboratory. The producers were informed, and a limit of intervention (50 mg . kg -1 ≈ 9 to 10 seeds . kg -1 ) was finally set for this undesirable component. The results of five years of controls show, at first, around 50% of contaminated samples. With appropriate measures, the level of contamination could be lowered in the following years. In parallel, the size of Ambrosia sp. seeds and the sieves to be used for routine analyses were checked. Ambrosia sp. seeds found in feed checked in Switzerland were seldom larger (“wider”) than 3.5 mm and never smaller than 1.5 mm. Several EU Member States started their own control and monitoring programs. The results of studies from Germany, Slovenia and Denmark, presented by their feed microscopists at the IAG meetings, indicate the presence of Ambrosia sp. seeds in 21 to 75% of the products put on the market. Keywords. Ambrosia artemisiifolia L., ragweed, bird feed, contaminant, seeds, microscopy, pollen, allergy. 1. IntroductIon Common ragweed (Ambrosia artemisiifolia L.) is an invading plant with highly allergenic pollen and important seed production. Originating from North America, its spread throughout different European countries has been thought to be linked in the past to the import of cereals (Kiss, 2007), and more recently with contaminated bird feed and the germination of seedlings at the foot of the trough. Other ways of propagation are movements of soil and vehicles together with contaminated seed lots. In 2005, Delabays et al. (2005) and Taramarcaz et al. (2005) described the situation in Switzerland and Brandes et al. (2006) similarly observed the distribution and dispersal of ragweed in Germany. The latter authors suggested: “At the present climatic conditions a continued occurrence of A. artemisiifolia in Central Europe is highly possible, even more so under global change conditions of elevated temperature and/or carbon dioxide”. As a consequence, and although ecological or economical damage (on the crop yield) was considered low, control measures were suggested because of the allergenic properties of ragweed pollen. Several measures to be applied on growing plants of known populations were elaborated, together with preventive measures concerning the dispersion of seeds (seed stock in soil or in vehicles, seed import as seed lot contaminant). At this juncture, presence of A. artemisiifolia in bird feed found on the market had been confirmed, especially in those mixtures containing sunflower seeds (Delabays et al., 2005; Brandes et al., 2006). In Switzerland, mandate was given to the official feed inspection unit of ALP (Agroscope Liebefeld-Posieux, the Federal Research Station) to monitor and control bird feed and raw materials with respect to the presence of A. artemisiifolia. Therefore, samples were collected on the market or in feed mills and the producers were instructed to respect the new intervention limit: no sample with more than 50 mg . kg -1 of whole A. artemisiifolia seeds would be tolerated. Shortly after this, the IAG
Transcript of Ragweed (Ambrosia sp.) seeds in bird feed · Ragweed (Ambrosia sp.) seeds in bird feed 41 500 g,...
BASE Biotechnol. Agron. Soc. Environ.201115(S1),39-44
Ragweed(Ambrosiasp.)seedsinbirdfeedGenevièveFrick(1),HeinrichBoschung(1),GudrunSchulz-Schroeder(2),GabrieleRuss(2),IgorUjčič-Vrhovnik(3),BredaJakovac-Strajn(3),DanielaAngetter(4),IngridJohn(4),JanStenJørgensen(5)(1)AgroscopeLiebefeld-PosieuxResearchStation(ALP).Tioleyre,4.P.O.Box64.CH-1725Posieux(Switzerland).E-mail:[email protected](2)Chemisches-undVeterinäruntersuchungsamtRhein-Ruhr-Wupper(CVUA-RRW).DeutscherRing,100.D-47798Krefeld(Germany).(3)UniversityofLjubljana.VeterinaryFaculty.NationalVeterinaryInstitute(NVI).UnitforPathologyofAnimalNutritionandEnvironmentalHygiene.Gerbiceva,60.SLO-1115Ljubljana(Slovenia).(4)LandeslaborBerlin-Brandenburg(LLBB).Templinerstraße,21.D-14473Potsdam(Germany).(5)TheDanishPlantDirectorate(DPD).Skovbrynet,20.DK-2800Lyngby(Denmark).
FiveyearsofmonitoringandcontrolforragweedseedsinbirdfeeddonebymembersoftheIAGworkinggroup(InternationalAssociationforFeedingstuffAnalysis,SectionFeedingstuffMicroscopy).
In2005,theSwissofficialfeedinspectionofAgroscopeLiebefeld-PosieuxResearchStation(ALP)wasmandatedtocheckbirdfeedandrawmaterialsforthepresenceofAmbrosia sp.seeds.Indeed,suchseedswerefoundinvaryingamountswhenanalyzed in the feedmicroscopy laboratory.Theproducerswere informed,anda limitof intervention (50mg.kg-1≈9 to10seeds.kg-1)wasfinallysetforthisundesirablecomponent.Theresultsoffiveyearsofcontrolsshow,atfirst,around50%ofcontaminatedsamples.Withappropriatemeasures,thelevelofcontaminationcouldbeloweredinthefollowingyears.Inparallel,thesizeofAmbrosia sp.seedsandthesievestobeusedforroutineanalyseswerechecked.Ambrosia sp.seedsfoundinfeedcheckedinSwitzerlandwereseldomlarger(“wider”)than3.5mmandneversmallerthan1.5mm.SeveralEUMemberStates started their own control andmonitoring programs.The results of studies fromGermany, Slovenia andDenmark,presentedbytheirfeedmicroscopistsattheIAGmeetings,indicatethepresenceofAmbrosia sp.seedsin21to75%oftheproductsputonthemarket.Keywords. Ambrosia artemisiifolia L.,ragweed,birdfeed,contaminant,seeds,microscopy,pollen,allergy.
1. IntroductIon
Common ragweed (Ambrosia artemisiifolia L.) is aninvadingplantwithhighlyallergenicpollenandimportantseed production. Originating from NorthAmerica, itsspreadthroughoutdifferentEuropeancountrieshasbeenthoughttobelinkedinthepasttotheimportofcereals(Kiss,2007),andmorerecentlywithcontaminatedbirdfeedandthegerminationofseedlingsatthefootofthetrough. Other ways of propagation aremovements ofsoilandvehiclestogetherwithcontaminatedseedlots.In2005,Delabaysetal.(2005)andTaramarcazetal.(2005)describedthesituationinSwitzerlandandBrandesetal.(2006)similarlyobservedthedistributionanddispersalofragweedinGermany.Thelatterauthorssuggested:“AtthepresentclimaticconditionsacontinuedoccurrenceofA. artemisiifoliainCentralEuropeishighlypossible,evenmoresounderglobalchangeconditionsofelevatedtemperatureand/orcarbondioxide”.Asaconsequence,andalthoughecologicaloreconomicaldamage(onthe
cropyield)wasconsideredlow,controlmeasuresweresuggestedbecauseoftheallergenicpropertiesofragweedpollen.Severalmeasurestobeappliedongrowingplantsof known populations were elaborated, together withpreventivemeasuresconcerningthedispersionofseeds(seedstockinsoilorinvehicles,seedimportasseedlotcontaminant).
Atthisjuncture,presenceofA. artemisiifoliainbirdfeedfoundonthemarkethadbeenconfirmed,especiallyinthosemixturescontainingsunflowerseeds(Delabaysetal.,2005;Brandesetal.,2006).
InSwitzerland,mandatewasgiventotheofficialfeedinspectionunit ofALP (AgroscopeLiebefeld-Posieux,the Federal Research Station) to monitor and controlbirdfeedandrawmaterialswithrespecttothepresenceofA. artemisiifolia.Therefore, sampleswere collectedon themarketor infeedmillsand theproducerswereinstructedtorespectthenewinterventionlimit:nosamplewith more than 50mg.kg-1 of whole A. artemisiifoliaseeds would be tolerated. Shortly after this, the IAG
40 Biotechnol. Agron. Soc. Environ. 201115(S1),39-44 FrickG.,BoschungH.,Schulz-SchroederG.etal.
feed microscopy working group, as a network forexchanginginformationandreferencematerial,togetherwith developing and standardizing methods, startedtowriteaprotocol for thedetectionandquantificationof A. artemisiifolia in bird feed, and several controlauthoritiesinEuropestartedtheirownscreening.
AlthoughthescreeningfocusesonA. artemisiifolia(themost abundant species of the genusAmbrosia inEurope) we cannot exclude that some of the selectedseeds belong to other Ambrosia species, A. trifidafor example. This could happen as the seeds havesimilarities.Consequently,wheneverpresenting resultsof the feed control, we will mentionAmbrosia sp. Inanycase,A. trifidaisalsoknowntoproduceallergenicpollen(D’amatoetal.,2007).
Thispapergivesanoverviewof theresults for thepresence of Ambrosia sp. in bird mixed feed or rawmaterialsanalyzedinSwitzerland(years2005to2009)andinfourotherlaboratoriesinEurope(twolaboratoriesinGermany,oneinSloveniaandoneinDenmark;years2006to2009).TheselaboratoriespresentedtheirworkatIAGmeetingsaspostersorlectures,andtheirresultsaresummarizedhere.
ThispaperalsodescribestherecordsdoneonthesizeoftheAmbrosia sp.seedsfoundinSwisssamples.
2. MaterIals and Methods
2.1. alP analyses
WhenthebirdfeedanalysisstartedatALPinsummer2005,noprotocolwasavailableforthisscreening.
First,referencematerialwasstudied.A. artemisiifoliaseeds were observed under the stereomicroscope atmagnificationsixtimesormore.Theseedsareenclosedindividuallyintheflowerbractswhichforma3-4mmlong and 2mm wide non-fleshy fruit presenting oneapicalthornandseveralotherspinesplacedasacrown(Figure 1).Thischaracteristicroughskinisusuallystillpresentontheseedsisolatedfromthefeedsamples;butinsomecases,themoreorlessnakedandglossyseedsarefound(Figure 2).
Second,birdfeedsamplesweretakenonthemarketandanamountofat least500gwas sieved in severalfractions.Intheyears2005to2007,thethreefollowingfractionswereexhaustivelyanalyzedbysearchingunderastereomicroscope:≤2.5mm;>2.5to≤3.5mm;>3.5to≤4.5mm.Thefraction larger than4.5mmwasnotanalyzed.
2.2. Method improvement
Toconsolidatetheprotocol,thesizeoftheAmbrosia sp.seedscollectedinthecheckedsamplesfromtheofficialcontrol and private clients in the first three yearswas
analyzedinmoredetail:seedswerefractionatedthroughthree sieves with a decreasing mesh-size by steps of0.5mm(2.5mmto1.5mm)tolookforthelowerlimit.
In the years 2008 and 2009, following the IAGmethod, only the fraction between 1.5 and 4mmwasanalyzed.
2.3. Monitoring in other european laboratories
The four other laboratories presenting results onAmbrosia sp. seeds in bird feed followed the IAGmethod(IAG,2009)usingsievesandasub-sampleof
Figure 1.TypicalAmbrosia artemisiifolia fruitcontainingone seed. The hairy fruit displays several characteristicthorns.
Figure 2. SeveralAmbrosia sp. seeds selected from feedsamples and showing diversity in size, color and level ofdestructionofthefruitenvelop.
2 mm
Ragweed(Ambrosiasp.)seedsinbirdfeed 41
500g, except for thegroupLLBB (Germany)wherethesub-samplesizewasonly25gin2008andthefirstpartof2009.AllresultswerecollectedasnumberofAmbrosia sp.seeds.kg-1.
3. results
3.1. alP results
In table 1, the resultsofallanalysesdoneatALP intheframeoftheofficialcontrolinSwitzerlandonthedetectionofAmbrosia sp.seedsinbirdmixedfeedorin their components (rawmaterials) are summarized.In general, the proportion of contaminated mixedfeed samples varied from 57% to 22%with a slightdecreasing tendency over the years. The percentageoftherawmaterialsampleswhichwerecontaminatedvariedbetween0and100%.
In 2005, from the 32 samples collected (9mixedfeed and 23raw materials), some contained largenumber of Ambrosia sp. seeds. From the 9 mixedfeed samples, 4 (44%)were contaminated above theinterventionlimit(setat50mg.kg-1,correspondingtoapproximately9seedsperkg)withamaximumof367perkg.Onesamplecontainedlessthan9Ambrosia sp.seeds per kg and 4 were Ambrosia sp.-free. From23rawmaterials, 4 (17%)were contaminated abovethe intervention limit,with amaximumof133seedsper kg. One sample was contaminated under theintervention limit and 18 were not contaminated.The largenumberofAmbrosia sp.-freerawmaterialscanbeexplainedbythefactthat,atfirst,allpossiblecomponentswerecheckedwhereasinfollowingyearsonlythemostat-riskcomponents(sunflower,sorghum,millet, hemp, etc.) were selected to be screened. In2006,animprovementofthesituationwasobservedinthelevelofcontaminationofthemixedfeedsamples:from 14 mixed feeds, 57% were contaminated, butonly2(14%)showedacontaminationslightlyabovethe intervention limit (11 and 19Ambrosia sp. seeds
perkg).SixmixedfeedscontainedaverylownumberofAmbrosia sp. seeds and 6wereAmbrosia sp.-free.Only4rawmaterialswerecheckedin2006,but2werehighly contaminated (up to 303 seeds per kg) and 2wereAmbrosia sp.-free. In the following threeyears,theproportionofmixedfeedscontaminatedabovetheintervention limit staid relatively low: 14% in 2007,22%in2008and11%in2009.However,somemixedfeeds and raw materials showed high numbers ofAmbrosia sp.seeds(upto220seedsperkg).Clearly,some raw materials are highly contaminated, but itseemstobepossibletoreduceaswellthepercentageof contaminated samples as the concentration ofAmbrosia sp.seedsinthemajorityofthesamples.
3.2. Method improvement
One goal of the different groups working on thecontamination of bird feed with Ambrosia sp. beingtheabilitytochecknumeroussamplesinalowtime-consuming manner, some work was invested in themethodofscreening.Toreducethesizeofthesampletobecheckedandtofacilitatethework,thecompulsorysieve-fractions were determined. At ALP, the totalnumberofseedsfoundinthedifferentsieve-fractionsin 2005 to 2007 was recorded.Figure3 shows thattheproportionof the seedssmaller than2.5mmwasstronglyreducedwithtime(434from498seeds=87%in2005;84from179seeds=47%in2006;55from163seeds=34%in2007).Ambrosia sp.seeds largerthan3.5mmwereveryseldomfound(onlytwoseedsfromatotalof840).
ToascertainthelowersizelimitoftheAmbrosia sp.seeds, the seeds collected during 3years were putthroughaseriesofsieves.Therepartitionoftheseedsinthesievesispresentedinfigure 4.Noseedssmallerthan1.5mmwerefound.Tenpercent(88 seeds)oftheAmbrosia sp.seedswerefoundinthesievebetween1.5and2.0mm.Mostoftheseedswerefoundbetween2.0and2.5mm(506 seeds=59%)whichreflectsthemeanwidthof the seed.Another31% (= 263seeds) of the
table 1.ResultsofthebirdmixedfeedandrawmaterialsanalysisdoneatALP(Switzerland)intheyears2005to2009. Ambrosia sp. contamination 2005 2006 2007 2008 2009Contaminatedsamples* Mixedfeed 56%(9) 57%(14) 39%(28) 50%(18) 22%(18) Rawmaterials 22%(23) 50%(4) 100%(3) 50%(2) 0%(1)>9seeds.kg-1(%ofallsamplesanalyzed) Mixedfeed 44% 14% 14% 22% 11%
Rawmaterials 17% 50% 33% 0% 0%Highestcontaminationlevel(seeds.kg-1) Mixedfeed 367 19 109 220 100 Rawmaterials 133 303 220 5 0
*Thecontaminatedsamplesaregiveninpercentageofallanalyzedsamples,thenumberofanalyzedsamplesareinbrackets.
42 Biotechnol. Agron. Soc. Environ. 201115(S1),39-44 FrickG.,BoschungH.,Schulz-SchroederG.etal.
seedswerelargerthan2.5mm.Theseresults,togetherwith other experiences in the practicing laboratories,ledustosetthesize-limitofthecompulsoryfractiontoanalyzeby1.5and4mmintheIAGmethod.Thisway,mostofthesunflowerseeds,forexample,arediscardedwithlittlechanceofmissingAmbrosia sp.seeds.
3.3. european laboratories screening results
In table 2, the results of four European controllaboratories who performed Ambrosia sp. screeningarepresented. Ingeneral, the situation resembles theone in Switzerlandwith a relatively high percentageof contaminated samples and high concentration ofAmbrosia sp. seeds at first and a tendency towardslowerlevels.
cVua-rrW (chemisches- und Veterinärunter-suchungsamt rhein-ruhr-Wupper, Krefeld, Germany). Thepercentage of contaminatedmixed feed samples
varied from92 to11%over theyears. In2006,2007and2008, thisGermangroupstated respectively 42, 57 and 0% of themixedfeedswithcontaminationlevelabovetheSwissinterventionlimitof9seedsperkg,andnoreallyhighcontaminationwasnoted (up to 31Ambrosia sp. seeds perkg). Concerning the raw materials, onecontained 61Ambrosia sp. seeds per kgin 2006, but in the following years, thelevelofcontaminationwaslow(maximum20seedsperkg).In2009onlyfoursampleswere analyzed, from which three werecontaminated at low levels (maximum of12Ambrosia sp.seedsperkg).
nVI (Veterinary Faculty, national Veterinary Institute, ljubljana, slovenia). An analysis of the situation inSlovenia in the winter season 2007/2008showedahighpercentageofcontaminatedmixedfeeds(70%)andrawmaterials(60%).The highly (above the Swiss interventionlimit)contaminatedmixedfeeds(40%oftheanalyzedmixedfeeds)containedupto292seedsperkg,whereasbytherawmaterials,thefivehighlycontaminatedsamples(50%of the analyzed raw materials) containedupto470Ambrosia sp.seedsperkg.Inthewinter season 2008/2009, the percentageof contaminated samples and the levelof contamination was lower: 50% of themixedfeedsand30%oftherawmaterialswere contaminated with Ambrosia sp.;30%and10%, respectively,of themixedfeedsandtherawmaterialscontainedmore
than9seedsperkg.Thehighestlevelofcontaminationwasalsolowerthantheyearbefore:42seedsperkgforthemixedfeedsand56fortherawmaterials.
dPd (the danish Plant directorate, lyngby, denmark). The evolution in Denmark in the firsttwo years of control seemed to tend in the directionopposite to the general trend. In 2008 more mixedfeeds (64%) and raw materials (44%) were highlycontaminated compared to 2007 (50% and 13% formixed feeds and raw materials, respectively). Thehighest levelofcontamination inmixedfeedsand inrawmaterialswashighover the twoyears2007and2008:185and252seedsperkg,respectively,in2007,and 112 and 847 in 2008 (Jørgensen, 2008). In theyear 2009, the percentage of contaminated samplesforbothmixedfeedsandtherawmaterialscamebackto the levels of 2007 (70% of contaminated mixedfeedsand29%ofcontaminatedrawmaterials),buttheaveragecontaminationlevelofseedsincontaminated
Figure 3. PooledresultsofthebirdfeedandrawmaterialsanalysisdoneatALP (Switzerland) in the years 2005 to 2007 considering the size-fractionwheretheseedswerefound.ResultsareexpressedinnumberofAmbrosiasp.seeds.
Figure 4. SizerepartitionofAmbrosiasp.seedsselectedbetween2005and2007frombirdfeedandrawmaterialsatALP(Switzerland).Foursieve-fractionswereanalyzedandthenumberofseedsrecorded.
Total in 2005 = 498 Total in 2006 = 179 434 84 55
64 93 108
0 2 0
1: ≤ 2.5 mm; 2: ≤ 3.5 and > 2.5 mm; 3: ≤ 4.5 and > 3.5 mm.
Total in 2007 = 163
500450400350300250200150100 50 0N
umber of A
mbrosia
seed
s
12
3
Sieve fractions
≤ 1.5 mm≤ 2.0 mm and > 1.5 mm
≤ 2.5 mm and > 2.0 mm
> 2.5 mm
Seeds 263 506
Num
ber of A
mbrosia
seed
s
88 0
600
500
400
300
200
100
0
Ragweed(Ambrosiasp.)seedsinbirdfeed 43
sampleswasverymuchlowerthaninprevioussurveys(Jørgensen,2009):only30%of themixed feedswerecontaminatedabovetheinterventionlimit.
llBB (landeslabor Berlin-Brandenburg, Potsdam, Germany). In this otherGerman laboratory, analyseswere started in 2008 with 10samples which werenot assigned directly by official authorities to themonitoringofAmbrosia sp.contaminationbuthadbeencollected for other analytical parameters. Therefore,the available sample weight (25g) was lower thanthe weight recommended in the IAG-method forAmbrosia sp. determination. In 2008, 33% of thesamplesanalyzedwerecontaminatedwithAmbrosia sp.,thehighestcontaminationwasfoundinarawmaterial(1,040Ambrosia sp. seeds per kg). In the first part of2009(table 2:2009/1)(againonabasisof25gsampleamount) the percentage of contaminated sampleswaslow (20% and 25% respectively formixed feeds andraw materials), but the level of contamination washigh (160 and 80seeds per kg respectively). In thesecond part of 2009, after change-over to an amountof 500g examination sample (table 2: 2009/2), 11%of the mixed feeds were again highly contaminated(maximum:144seedsperkg),andtheonlyrawmaterial
wasfoundtobecontaminatedwithAmbrosia sp.atlowlevel(6seedsperkg).
4. dIscussIon
The analysis of bird feed and raw materials (mostlysunflowerseeds)inSwitzerlandandthreeotherEuropeancountries in the years 2005 to 2009 confirmed that alarge proportion of thesemixtureswere contaminatedwithAmbrosia sp. In thesouthernandcentralpartsofEurope, the seeds of Ambrosia artemisiifolia whichreach the ground and stay in the soil can germinateand the plant originating from these seedlings maydevelopuptofloweringandproducealargequantityofallergenicpollen.Itseemslogical totrytoreducethiswayofdispersal,evenmorewhenconsideringthefactthattheseplantsoftengrowinprivateorpublicgardens.In Switzerland and Germany (BVL, 2009), pressureset on the producers of bird feed andmeasures takenhad a noticeable effect on the level of contaminationin both rawmaterials seed lots intended for bird feedandinthebirdfeedsthemselves,althoughalowlevelof contamination seems unavoidable. In Slovenia thedecreased number of contaminating seeds in the bird
table 2.ResultsofthebirdfeedandrawmaterialsanalysisdoneinlaboratorisinthreeEuropeancountriesintheyears2006to2009. Ambrosia sp. contamination cVua-rrW nVI
2006 2007 2008 2009 2007/08 2008/09Contaminatedsamples Mixedfeed 92%(12) 71%(7) 11%(9) 67%(3) 70%(10) 50%(10) Rawmaterials 25%(4) 100%(2) 100%(1) 100%(1) 60%(10) 30%(10)>9seeds.kg-1(%of Mixedfeed 42% 57% 0% 33% 40% 30%allsamplesanalyzed) Rawmaterials 25% 0% 100% 0% 50% 10%Highestcontamination Mixedfeed 24 31 2 12 292 42level(seeds.kg-1) Rawmaterials 61 3 20 2 470 56 dPd llBB
2007 2008 2009 2008* 2009/1* 2009/2Contaminatedsamples Mixedfeed 75%(8) 73%(11) 70%(10) 33%(3) 20%(10) 11%(18) Rawmaterials 25%(8) 67%(9) 29%(7) 29%(7) 25%(4) 100%(1)>9seeds.kg-1(%ofall Mixedfeed 50% 64% 30% 33% 20% 11%samplesanalysed) Rawmaterials 13% 44% 14% 29% 25% 0%Highestcontamination Mixedfeed 185 112 101 40 160 144level(seeds.kg-1) Rawmaterials 252 847 32 1040 80 6
CVUA-RRW(Chemisches-undVeterinäruntersuchungsamtRhein-Ruhr-Wupper,Krefeld)andLLBB(LandeslaborBerlin-Brandenburg,Potsdam)areGermananalysts,NVIstandsforVeterinaryFaculty,NationalVeterinaryInstitute,Ljubljana,SloveniaandDPDforTheDanishPlantDirectorate.Forthemixedfeedsandrawmaterials,thecontaminatedsamplesinpercentageofallanalyzedsamples,thenumberofanalyzedsamples(inbrackets),thepercentageofallsampleswithacontaminationabovenineAmbrosiasp.seeds.kg-1,aswellasthehighestcontaminationfoundinthesamples(inAmbrosiasp.seeds.kg-1)aregiven;*Analysisdoneon25g.
44 Biotechnol. Agron. Soc. Environ. 201115(S1),39-44 FrickG.,BoschungH.,Schulz-SchroederG.etal.
feedputonthemarketwasalsonoticed.Ontheotherhand, in Denmark the situation did not improve in2008 compared to 2007, but improved in 2009whenconsideringthecontaminationlevelofthecontaminatedsamples. In this country, the climatic situation mightstillpreventtheragweedplantstoreproducebyseeds,but pollen production is possible and the allergenicconsequences for the population will still be present.Thissituationprevails inFinland too (Pohto,personalcommunication). Also, Ambrosia artemisiifolia seedscansurviveinsoilformorethan40years(Baskinetal.,1977)andbecapableofgerminating.
To help the analysts with the task of analyzingbird feed, an official standardization of the methodis welcome. One parameter to check was the choiceof the fraction to analyze. Fractionating the sampleby sieving through a column of sieves is little workand allows the removal of all particles of irrelevantsize. This is particularly interesting when analyzingsamples of sunflower seeds, for example, because ofthedifferent seed size ofAmbrosia sp. and sunflower.Checking particles ofmostly the same size under thestereomicroscope or a magnifying lamp is also lesstiringandmoreefficientthananalyzingaheterogeneoussample.Aswell,removingthedustandsmallparticlesmakestheshiftingoftheseedsinadishwithaspatulamoreconvenient.
RecordingthesizeoftheseedsfoundinbirdfeedwasdoneatALPduringthefirstthreescreeningcampaigns(2005to2007).Togetherwiththedeterminationofthelimitsofseedsize(minimum1.5mm;maximum4mm),these records brought unexpected information: thedistributionoftheindividualseedsizevariedwithtimetoward larger seeds.Although itmightbedue topre-harvestgrowingconditionsorthepresenceofdifferentspeciesofthegenusAmbrosia sp.,thiscouldalsobeaconsequenceofapost-harvestingcleaningtreatmentoftherawmaterialswhicheliminatedthesmallerbutnotthelargerseeds.Inthisregard,itwouldbeimportanttocheckwhat isdonewith the residueaftercleaning, tomakesurethatitdoesnotendupbeingdiscardedintheopennature.
The presence of larger seeds in a sample withlow contamination level was also noted in a ringtestorganized to check the IAGmethod (datanotyetpublished).
A general remark is the fact that the method isrelatively easy to set up thanks to the characteristicfeaturesoftheAmbrosia sp.seed(botanicallyspeakinga fruit,figure 1).Also, onlywhole seeds and not thefragments are of interest because the germinationpotentialsolelyisrelevant(nodirecttoxicity).Still,theanalysisoflargesamplescanbetediousifthemixturecontainsmostlyseedsofasizesimilartoAmbrosia sp.(forexample:hemp,sorghumormilletseeds).Also,asdescribedaboveanddocumentedinfigure 2,thepossible
diversityinthesize,colorandlevelofdestructionofthefruit around the seed can represent a challenge to themicroscopists.
Finally, as a side effect to this work, all analystsmentioned a valuable increase of knowledge on thepossiblecontaminantsofseedmixes:Datura stramoniumseedswere recorded, sclerotia from fungi,otherweedseedsandstoneswereobservedinsomesamples.
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