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Mycelial growth and ochratoxin A production by Aspergillus section Nigri on simulated grape medium in modified atmospheres
Author(s) -
Valero A.,
Begum M.,
Hocking A.D.,
Marín S.,
Ramos A.J.,
Sanchis V.
Publication year - 2008
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2008.03760.x
Subject(s) - ochratoxin a , mycelium , aspergillus , ochratoxin , food science , biology , section (typography) , microbiology and biotechnology , mycotoxin , botany , computer science , operating system
Aims: To evaluate the impact of modified atmosphere packaging on in vitro growth of Aspergillus carbonarius and Aspergillus niger , and possible effects on ochratoxin A (OTA) biosynthesis. Methods and Results: Ochratoxigenic isolates belonging to the species A. carbonarius and A. niger were grown on a synthetic grapejuice medium (SNM) and packaged in combinations of controlled O 2 (1% and 5%) and CO 2 levels (0% and 15%), and in air as a control. Colony diameters were recorded every 3 days up to 21 days, and OTA was analysed after 7, 14 and 21 days. The greatest reductions in mycelial growth rate were observed at 1% O 2 followed by 1% O 2 /15% CO 2 , whereas 5% O 2 stimulated the growth of all isolates. OTA production by A. carbonarius and A. niger isolates was minimized at 1% O 2 /15% CO 2 and 1% O 2 , respectively, after 7 days of incubation. Maximal OTA accumulation after 7 days was observed for all isolates in the control pack and at 5% O 2 . Conclusions: Of the atmospheres tested, only 1% O 2 combined with 15% CO 2 consistently reduced fungal growth and OTA synthesis by A. carbonarius and A. niger . Significance and Impact of the Study: Storage under modified atmospheres is unlikely to be suitable as the sole method for OTA minimization and grape preservation; other inhibitory factors are necessary.