Intraspecific variability of growth and mycotoxin production of Aspergillus carbonarius under marginal conditions

DAIANA GARCIA; ANTONIO J. RAMOS; VICENTE SANCHIS; SONIA MARÍN

Noordwijkerhout

Conferencia; The world mycotoxin forum 6th conference; 2010

Mycotoxin contamination of food products is an important health hazard of a growing interest around the world. Aspergillus carbonarius has been considered the main species in ochratoxin A (OTA) accumulation in some food products. Generally, foods and feeds are stored at suboptimal conditions for mould growth. Different environmental factors, like temperature, activity water (aw), pH, etc., could influence on the variability intra-species in their growth capability and mycotoxin production, and this might be increased when marginal conditions exist. The aim of this research was to assess the impact of suboptimal environmental conditions on the intraspecific variability of A. carbonarius growth and OTA production using thirty isolates of A. carbonarius. Petri dishes with SNM were inoculated centrally with a needlepoint load. Three aw/temperature conditions were tested, an optimal one (0.98aw/25ºC) and two suboptimal ones: 0.90aw/25º and 0.98aw/37ºC as suboptimal water activity and temperature, respectively. For each condition, 12 Petri dishes were inoculated, and colony growth and OTA production was measured along time. ANOVA revealed significant differences among growth rate (μ) and lag phase (λ) within the 30 assayed isolates. Coefficients of variation (CV%) revealed a wider dispersion of growth rates at 0.90aw/25ºC compared to 0.98aw/25ºC. However, regarding lag phases dispersion they were similar at 0.98aw/25ºC and 0.90aw/25ºC and wider at 0.98aw/37ºC. There were significant differences (p