Early Detection of Antibodies against Various Structural ...
Using Rhizopus sp. against the growth of Aspergillus ...
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Using Rhizopus sp. against the growth of Aspergillus carbonarius as a potential biological control method of ochratoxin A contamination in raw cocoa beans a Department of Food Science and Technology, University of Nangui Abrogoua, 02 Bp 801 Abidjan 02, Côte d'Ivoire b UMR Qualisud, CIRAD - TA-B 95/16, 73 rue JF Breton, 34398 Montpellier Cedex 5, France Didier Kra Brou KEDJEBO a , Tagro Simplice GUEHI a , Maï Koumba KONE a , Pascaline ALTER b , Noël DURAND b , Renaud BOULANGER b , Angélique FONTANA b , Didier MONTETb Ochratoxin A (OTA) is a carcinogenic and nephrotoxic mycotoxin produced by fungal species belonging to Aspergillus and Penicillium genus. OTA occurrence in foodstuffs depends on the climate during harvest and on the post-harvest storage conditions. Among known ochratoxins, OTA currently contaminates crops. Due to its prevalence and toxicity, OTA occurrence development conditions in raw cocoa beans were previously studied during post-harvest treatments. This research aimed to investigate on the biological control of OTA excretion in cocoa. Material and Methods Cocoa Cocoa pods used were the variety of clone CLM 99 harvested at Trinidad Tobago in 2013. Analyzes • Cocoa pod inocula-on by Rhizopus Rhizopus sp. isolated from roAen cocoa pods opened aBer 7 days delay and A. carbonarius isolated from coffee cherries were separately grew on PDA agar for 5 days at 25°C (Figure 1). Different conidia inocula were prepared from calibrated suspensions at 10 2 , 10 4 and 10 6 conidia per millileter. Then 1 mL of each prepared inoculum was asepPcally injected using a syringe inside health cocoa pods. Inoculated cocoa pods were incubated in a climaPc chamber at 30°C, 60% relaPve humidity for 4 or 8 days. • Ochratoxin A content measurement OTA was extracted from cocoa beans sourced from inoculated pods and then separated by immuno-affinity, idenPfied by HPLC and quanPfied by spectro-fluorescence detector. Results Table I presents the photographs of beans inside cocoa pods aBer inoculaPon with various concentraPons of A. carbonarius and Rhizopus sp. conidia suspensions. Figure 2 indicates OTA content for cocoa beans sourced from: • Pods inoculated with 10 4 conidia per mL of A. carbonarius and 10 4 conidia per mL of Rhizopus sp . - incubated for 4 days: no OTA producPon was observed - incubated for 8 days: OTA producPon of 37 µg.kg -1 was highlighted when control presented no OTA producPon. • Pods inoculated with 10 4 conidia per mL of A. carbonarius and 10 6 conidia per mL of Rhizopus sp. - incubated for 4 days: no OTA producPon was noPced - incubated for 8 days: OTA producPon of 5.6 µg.kg -1 was obtained against 0 µg per kg for the control. • Pods inoculated with 10 4 conidia per mL of Rhizopus sp. and 10 6 conidia per mL of A. carbonarius - incubated for 4 days: 36.3 µg.kg -1 of OTA was recorded - incubated for 8 days: 6.2 µg.kg -1 of OTA was observed Conclusion Durand, N., 2012. Dynamique des populations microbiennes au cours du traitement post-récolte du café et relations interspécifiques entre souches ochratoxinogènes. Thèse de Doctorat, 243 P. Université de Montpellier II, Sciences et TechniquesduLanguedoc. Ponsone, M.L., Chiotta, M.L., Combina, M., Dalcero, A. and Chulze,S.,2011. Biocontrolasastrategytoreducetheimpactof ochratoxinAand Aspergillus section Nigri ingrapes. International JournalofFoodMicrobiology ,151:70-77. Varga, J., Peteri, Z., Tabori, K., Teren, J. and Vagvolgyi, C., 2005. Degradation of ochratoxin A and other mycotoxins by Rhizopus isolates. International Journal of Food Microbiology ,99: 321-328. References Conception: Cirad, Martine Duportal, June 2017 – © photos Kra Brou Didier Kedjebo Rhizopus sp appeared as a promising biological control fungal agent for OTA production in raw cocoa beans. As the fungal growth in raw cocoa beans constituted a serious qualitative default, further investigation must be done on the identification of the metabolites leading to the control of OTA excretion in cocoa. Figure 1. Cultures of Aspergillus carbonarius (A) and Rhizopus sp. (B) on PDA agar used for cocoa beans inoculation inside pods Table I. Photographs of beans inside cocoa pods inoculated with suspensions of various concentrations in A. carbonarius and Rhizopus sp. conidia Corresponding author: [email protected] Concentration of fungal conidia (conidia.mL -1 ) Incubation time (days) A.carbonarius Rhizopus sp A.carbonarius Rhizopus sp A.carbonarius Rhizopus sp A.carbonarius Rhizopus sp 0 10 4 10 6 10 4 10 4 10 6 4 8 Figure 2. OTA content of cocoa beans from pods inoculated with various concentrations of A. carbonarius and Rhizopus sp conidia suspensions of
Transcript of Using Rhizopus sp. against the growth of Aspergillus ...
Using Rhizopus sp. against the growth of Aspergillus carbonarius as a potential biological control method of ochratoxin A contamination in raw cocoa beans
a Department of Food Science and Technology, University of Nangui Abrogoua, 02 Bp 801 Abidjan 02, Côte d'Ivoire b UMR Qualisud, CIRAD - TA-B 95/16, 73 rue JF Breton, 34398 Montpellier Cedex 5, France
Didier Kra Brou KEDJEBOa, Tagro Simplice GUEHIa, Maï Koumba KONEa, Pascaline ALTERb, Noël DURANDb, Renaud BOULANGERb, Angélique FONTANAb, Didier MONTETb
Ochratoxin A (OTA) is a carcinogenic and nephrotoxic mycotoxin produced by fungal species belonging to
Aspergillus and Penicillium genus. OTA occurrence in foodstuffs depends on the climate during harvest
and on the post-harvest storage conditions. Among known ochratoxins, OTA currently contaminates
crops. Due to its prevalence and toxicity, OTA occurrence development conditions in raw cocoa beans
were previously studied during post-harvest treatments. This research aimed to investigate on the
biological control of OTA excretion in cocoa.
Material and MethodsCocoa CocoapodsusedwerethevarietyofcloneCLM99harvestedatTrinidadTobagoin2013.
Analyzes •Cocoapodinocula-onbyRhizopusRhizopussp.isolatedfromroAencocoapodsopenedaBer7daysdelayandA.carbonariusisolatedfromcoffeecherrieswereseparatelygrewonPDAagarfor5daysat25°C(Figure1).Differentconidiainoculawerepreparedfromcalibratedsuspensionsat102,104and106conidiapermillileter.Then1mLofeachpreparedinoculumwasasepPcallyinjectedusingasyringeinsidehealthcocoapods.InoculatedcocoapodswereincubatedinaclimaPcchamberat30°C,60%relaPvehumidityfor4or8days.•OchratoxinAcontentmeasurementOTAwasextractedfromcocoabeanssourcedfrominoculatedpodsandthenseparatedbyimmuno-affinity,idenPfiedbyHPLCandquanPfiedbyspectro-fluorescencedetector.
ResultsTableIpresentsthephotographsofbeansinsidecocoapodsaBerinoculaPonwithvariousconcentraPonsofA.carbonariusandRhizopussp.conidiasuspensions.Figure2indicatesOTAcontentforcocoabeanssourcedfrom:
•Podsinoculatedwith104conidiapermLofA.carbonariusand104conidiapermLofRhizopussp.-incubatedfor4days:noOTAproducPonwasobserved- incubatedfor8days:OTAproducPonof37µg.kg-1washighlightedwhencontrolpresentednoOTAproducPon.
•Podsinoculatedwith104conidiapermLofA.carbonariusand106conidiapermLofRhizopussp.-incubatedfor4days:noOTAproducPonwasnoPced-incubatedfor8days:OTAproducPonof5.6µg.kg-1wasobtainedagainst0µgperkgforthecontrol.
•Podsinoculatedwith104conidiapermLofRhizopussp.and106conidiapermLofA.carbonarius-incubatedfor4days:36.3µg.kg-1ofOTAwasrecorded-incubatedfor8days:6.2µg.kg-1ofOTAwasobserved
Conclusion
Durand,N.,2012.
Dynamiquedesp
opulationsmicrobi
ennes
au cours du trai
tementpost-réco
lte du café et r
elations
interspécifiques e
ntre souches och
ratoxinogènes. Th
èse de
Doctorat, 243 P.
Université de Mo
ntpellierII, Scienc
es et
TechniquesduLan
guedoc.
Ponsone,M.L.,Ch
iotta,M.L.,Comb
ina,M.,Dalcero,
A.and
Chulze,S.,2011.B
iocontrolasastrate
gytoreducetheim
pactof
ochratoxinAandA
spergillussectionN
igriingrapes.Interna
tional
JournalofFoodMic
robiology,151:70-
77.
Varga,J.,Peteri,Z.,
Tabori,K.,Teren,J
.andVagvolgyi,C.,
2005.
Degradationofoch
ratoxinAandothe
rmycotoxinsbyRh
izopus
isolates.Internatio
nal Journal of Fo
od Microbiology,
99 :
321-328.
References
Conc
eptio
n: C
irad,
Martine D
uport
al,
June
201
7 – ©
pho
tos K
ra B
rou
Did
ier K
edje
bo
Rhizopus sp appeared as a promising biological control fungal agent for OTA
production in raw cocoa beans. As the fungal growth in raw cocoa beans constituted
a serious qualitative default, further investigation must be done on the identification
of the metabolites leading to the control of OTA excretion in cocoa.
Figure 1. Sampling during post-harvest processing of cocoa
Figure 1. Cultures of Aspergillus carbonarius (A) and Rhizopus sp. (B) on PDA agar used for cocoa beans inoculation inside pods
Table I. Photographs of beans inside cocoa pods inoculated with suspensions of various concentrations in A. carbonarius and Rhizopus sp. conidia
Corresponding author: [email protected]
Concentration of fungal conidia (conidia.mL-1)
Incubation
time (days)
A.carbonarius Rhizopus sp A.carbonarius Rhizopus sp A.carbonarius Rhizopus sp A.carbonarius Rhizopus sp
0 104 106 104 104 106
4
8
Figure 2. OTA content of cocoa beans from pods inoculated with various
concentrations of A. carbonarius and Rhizopus
sp conidia suspensions of
