Predictive Modeling and Validation on Growth, Production of Asexual Spores and Ochratoxin A of <i>Aspergillus Ochraceus</i> Group under Abiotic Climatic Variables

• Main Authors: Ahmed Abdel-Hadi, Bader Alshehri, Mohammed Waly, Mohammed Aboamer, Saeed Banawas, Mohammed Alaidarous, Manikandan Palanisamy, Mohamed Awad, Alaa Baazeem
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Microorganisms
• Subjects: <i>Aspergillus westerdijkiae</i>; <i>Aspergillus steynii</i>; water activity; temperature; growth rate; sporulation
• Online Access: https://www.mdpi.com/2076-2607/9/6/1321

This study aimed to generate predictive models for growth, sporulation, and ochratoxin A (OTA) production under abiotic climatic variables, including temperatures (15–35 °C) and water activity levels (0.99–0.90 a_w) by <i>Aspergillus ochraceus</i> group. The data were divided into three sets: one for training, one for testing, and the third one for model validation. Optimum growth occurred at 0.95 a_w and 25 °C and 0.95 a_w and 30 °C for <i>A. westerdijkiae</i> and <i>A. steynii</i>, respectively. Significantly improved <i>A. westerdijkiae</i> and <i>A. steynii</i> spore production occurred at 0.95 a_w and 20 °C and 0.90 a_w and 35 °C, respectively. <i>A. steynii</i> and <i>A. westerdijkiae</i> produced the majority of OTA at 35 °C and 0.95 a_w and 25–30 °C at 0.95–0.99 a_w, respectively. The accuracy of the third-order polynomial regression model reached 96% in growth cases, 94.7% in sporulation cases, and 90.9% in OTA production cases; the regression coefficients (R2) ranged from 0.8819 to 0.9978 for the <i>Aspergillus ochraceus</i> group. A reliable agreement was reached between the predicted and observed growth, sporulation, and OTA production. The effects of abiotic climatic variables on growth, sporulation, and OTA production of <i>A. ochraceus</i> group have been effectively defined, and the models generated were responsible for adequately predicted and validated models against data from other strains within <i>A. ochraceus</i> group that had been published in the literature under the current treatments. These models could be successfully implemented to predict fungal growth and OTA contamination on food matrices for these strains under these conditions.