Effect of water activity and temperature on the growth of Eurotium species isolated from animal feeds

GRECO, M.; PARDO, A.; POSE, G.; PATRIARCA, A.

REVISTA IBEROAMERICANA DE MICOLOGIA

ASOCIACION ESPANOLA MICOLOGIA-AEM

Año: 2018 vol. 35 p. 39 - 48

1130-1406

Growth of xerophilic fungi represents a relevantproblem due to their ability to grow at low water activities causing spoilage oflow and intermediate moisture foods, stored goods and animal feeds, with theconsequent economic losses. The combined effect of water activity and temperatureof four Eurotium species isolated from animal feeds was investigated. E.amstelodami, E. chevalieri, E. repens and E. rubrum were grown at 5,15, 25, 37 and 45˚C on Malt Extract Agar adjusted with glycerol in the range ofwater activities 0.710-0.993. The cardinal model proposed by Rosso andRobinson (2001) was applied to fit growth data, with water activity as factorat fixed temperatures, obtaining three cardinal water activities (awmin, awmax, awopt) and thespecific growth rate at the optimum aw(µopt).A probabilistic model was also applied to define the interface between growthand no-growth. The cardinal model provided an adequate estimation of optimal aw for growth and maximumgrowth rate. Probabilistic model showed a good performance to fitgrowth/no-growth cases in the predicted range. The results presented here couldbe applied to predict Eurotiumspecies growth in feed matrices.