“Intensification of vaporization by decompression to vacuum” as an advanced approach for decontaminating wheat from Aspergillus flavus spores: Effects on key quality attributes

Aspergillus flavus is an aflatoxigenic mold that may infect harvested wheat kernels. Under suitable temperatures and humidity, it produces AFB1, a potent mutagenic and carcinogenic compound affecting both humans and animals. Preventing or reducing crop contamination by inactivating the fungal spores is therefore essential. This study assessed, for the first time, the effectiveness of a novel thermo-mechanical process called IVDV (Intensification of Vaporization by Decompression to Vacuum) in decontaminating wheat kernels artificially inoculated with A. flavus spores. In this method, contaminated kernels were first exposed to saturated steam and then subjected to an abrupt decompression to vacuum. The sudden pressure drop contributes to disrupting microbial structures and minimizes heat damage. Using Response Surface Methodology, log reduction levels and moldiness percentages were measured at various combinations of saturated steam time and pressure. Moreover, colorimetric and textural assessments were conducted to evaluate the quality of wheat. Predictive models for log reduction, moldiness, and aw were established. Multiple optimization revealed time-pressure combinations that achieved 0 % moldiness level, water activity of 0.38, and a log reduction of >8.2, ensuring total A. flavus inactivation in wheat. Importantly, IVDV treatment conditions at 1.8 - 3.5 bar for 20 - 80 s did not significantly alter kernel color, size, or texture. These results support the use of IVDV as an effective post-harvest preventive strategy against AFB1 formation in wheat, offering both microbial safety and quality preservation, with potential for industrial-scale application.