Interactive Inhibition of Aflatoxigenic Aspergillus flavus and Ochratoxigenic Aspergillus carbonarius by Aspergillus oryzae under Fluctuating Temperatures

Abstract

This study aimed to evaluate the effectiveness of A. oryzae in inhibiting aflatoxin B1 (AFB1) and ochratoxin A (OTA) production by A. flavus and A. carbonarius, respectively, under shifting temperatures. A. oryzae was tested on different agar, namely coconut cream agar (CCA) and chili-based agar to figure out the variation in the effectiveness of A. oryzae on the most appropriate medium for A. flavus and A. carbonarius to produce mycotoxin and under natural condition where they are predominantly found. On CCA, the temperatures applied were 20, 30, 35, 40, 20/30, 20/35, and 20/40 °C, while on chili-based agar, the temperatures imposed were 20, 40, and 20/40 °C, at varied water activity of 0.92 and 0.97aw. The findings indicated that A. oryzae was much more effective in inhibiting the growth of A. flavus rather than A. carbonarius, yet it was able to inhibit higher OTA concentration than AFB1 at fluctuating temperatures on CCA as the most appropriate medium for A. flavus and A. carbonarius. A. oryzae effectively inhibited AFB1 and OTA at static temperature of 20 °C and water activity of 0.97aw on chili-based agar. Under fluctuating temperatures (20/40 °C), A. oryzae was also able to control mycotoxin, particularly OTA at high water activity (0.97aw).

Investigation of the Physicochemical Properties and its Correlation during Koji-Moromi Fermentation Stage of Production Soy Sauce Naturally Brewed in Central Java, Indonesia

“…The aw value, as of Fig 2 ., shows that it remained within acceptable limits during the koji stage and did not exceed 0.8. This is consistent with Dwipa et al [44], who states that mold can only thrive in an aw environment that does not exceed 0.8, implying that the koji fermentation process is complete. The reduction of aw during 46 hours of koji fermentation, mainly by A. oryzae, prevented spoilage or contamination by unwanted microorganisms with a specific temperature control between 30 and 43°C [27].…”

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

“…The International Agency for Research on Cancer (IARC) classified the AFB1 and naturally occurring mixture of aflatoxins as carcinogenic to humans (Group 1) [9]. Aspergillus flavus and A. parasiticus are the major producers of aflatoxins, and are responsible for the largest proportion of these mycotoxins occurring in various agricultural commodities [10].…”