[Influence of the interaction of temperature and water activity on the production of ochratoxin A and the growth of Aspergillus niger, Aspergillus carbonarius and Aspergillus ochraceus on coffee-based culture medium].
In the present study, the effect of temperature and water activity on fungal growth and ochratoxin production on coffee-based medium was assessed. Optimal growth of three Aspergillus strains was observed in the same ecological conditions, namely 30 degrees C and 0.99 water activity. Maximal daily growth is 11.2, 6.92, and 7.22 mm/day for Aspergillus niger, Aspergillus carbonarius, and Aspergillus ochraceus, respectively. However, ecological conditions for optimal ochratoxin production vary according to the toxinogenic strain, with water activity as a limiting factor. Such an ochratoxin A production is inhibited at 42 degrees C and 0.75 water activity. Correspondence between laboratory tested water activity and that measured on a sun-dried ripe cherry batch shows that the first 5 days of drying are critical for fungal growth and ochratoxin A production. Accordingly, artificial drying of cherries at temperatures above 42 degrees C will impede not only fungal growth but also contamination with ochratoxin A.
Kouadio
Ahou Irène
AI
Laboratoire de génie chimique, Unité mixte de recherche 5503, Equipe Génie des systèmes microbiens , INP/ENSAT, Avenue de l'Agrobiopole, B.P. 32607 Auzeville Tolosane, 31326 Castanet Tolosan, Toulouse, France.
Lebrihi
Ahmed
A
Agbo
Georges N' Zi
GN
Mathieu
Florence
F
Pfohl-Leszkowiz
Annie
A
Dosso
Mireille Bretin
MB
D001230:Aspergillus / Q000254:growth & development* / Q000378:metabolism*; D003069:Coffee / Q000382:microbiology*; D009793:Ochratoxins / Q000096:biosynthesis*; D013696:Temperature; D014867:Water / Q000378:metabolism
D003069:Coffee; D009793:Ochratoxins; D014867:Water; C025589:ochratoxin A