Filamentous fungi producing ochratoxin a during cocoa processing in Cameroon.
Ochratoxin A (OTA) is the main mycotoxin occurring in cocoa. A study was conducted in Cameroon to assess how filamentous fungi and toxigenesis were affected by the type of cocoa post-harvest treatment (boxes or heaps). The filamentous fungi isolated were almost identical when fermentation was carried out in boxes or heaps, with the presence of abundant black Aspergillus filamentous fungi: A. niger and A. carbonarius. Filamentous fungi were more abundant at the end of the harvesting season. Factors affecting bean integrity (poor handling, deferred processing) resulted in a qualitative and quantitative increase in contamination, when the total number of filamentous fungi could reach a maximum value of 5.5+/-1.4x10(7) CFU g(-1) and black Aspergilli a maximum value of 1.42+/-2.2x10(7) CFU g(-1). A toxigenesis study showed that Aspergillus carbonarius was the main OTA-producing strain isolated. Its maximum production could reach 2.77 microg g(-1) on rice medium. Aspergillus niger strains did not always produce OTA and their toxigenesis was much lower. Fermented dried cocoa from poor quality pods was the most contaminated by OTA: up to 48 ng g(-1).
Mounjouenpou
Pauline
P
Institut de Recherche Agricole pour le Développement, BP 2067, Yaoundé, Cameroon.
Gueule
Dominique
D
Fontana-Tachon
Angélique
A
Guyot
Bernard
B
Tondje
Pierre Roger
PR
Guiraud
Joseph-Pierre
JP
D001230:Aspergillus / Q000254:growth & development / Q000378:metabolism*; D002099:Cacao / Q000382:microbiology*; D002163:Cameroon; D002273:Carcinogens / Q000032:analysis / Q000302:isolation & purification; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005285:Fermentation; D005506:Food Contamination / Q000032:analysis*; D005511:Food Handling / Q000379:methods*; D009793:Ochratoxins / Q000096:biosynthesis* / Q000302:isolation & purification; D012621:Seasons
D002273:Carcinogens; D009793:Ochratoxins; C025589:ochratoxin A