Comparative study on the effect of temperature and water activity on Aspergillus flavus and Aspergillus carbonarius isolates growth and mycotoxin production on a chili powder medium

Abstract

This study was aimed at determining the effect of temperature and water activity (a w ) on the radial growth of Aspergillus flavus and A. carbonarius isolated from dried chili and their production of aflatoxin B1 (AFB1) and ochratoxin A (OTA), respectively. The isolates were grown on a synthetic chili-based medium, and growth and mycotoxin production were studied following a central composite design. The diameter of each colony was measured, and mycotoxins were extracted from the medium after 7 days of incubation at each different combination of temperature and a w . The analysis of variance results showed that temperature, a w , and their interaction had significant effects on growth and mycotoxin production. Response surface analysis showed that both strains were able to grow within a wide range of temperatures (22.93-37.07°C) and a w values (0.885-0.984), but production of AFB1 and OTA was not detected at 37.

Modeling the Thermal Inactivation of Ascospores from Heat-Resistant Molds in Pineapple Juice and Evaluating Disinfection Efficiency of Sodium Hypochlorite and Chlorine Dioxide

“…The RMSE score measures the closeness between the predicted values and the observed values, with lower values indicating a better fit. On the other hand, the R 2 value of 1 suggests a strong correlation between the model predictions and the actual experimental data [39]. In this study, both the log-linear model and the Weibull model exhibited similar RMSE values, suggesting that they both adequately fit the inactivation data.…”

Impacts of Temperature and Water Activity Interactions on Growth, Aflatoxin B1 Production and Expression of Major Biosynthetic Genes of AFB1 in Aspergillus flavus Isolates

“…The response surface analysis revealed that both isolates could develop at temperatures between 22 and 37 °C and a w values between 0.88 and 0.98, although the production of AFB1 did not occur at temperatures below 37 °C at 0.90 a w . The authors suggest that the a w in harvested chili should be immediately decreased to less than 0.90 by an effective drying method to prevent fungal growth and AFB1 production [ 21 ]. Two A. flavus isolates isolated from imported raw peanuts were studied for growth and AFB1 production using a full factorial design with seven a w levels (0.85–0.98 a w ) and five temperature levels (20–40 °C).…”

Optimization and Validation of Dispersive Liquid–Liquid Microextraction for Simultaneous Determination of Aflatoxins B1, B2, G1, and G2 in Senna Leaves and Pods Using HPLC-FLD with Pre-Column Derivatization

“…In addition, the lack-of-fit values were not significant (p-value > 0.05), indicating that the model was adequate for predicting the responses. Goodness-of-fit of the proposed models was also evaluated based on R 2 , adjusted R 2 , and predicted R 2 [32], which were all greater than 0.90 for all aflatoxins. A suitable model should have an R 2 no less than 0.75 [33].…”