Microwave decontamination process for hummus: A computational study with experimental validation

There has been an increasing demand for healthy snacks, and hummus is preferred as a plant-based product its rich protein content. Its increased consumption, on the other hand, has raised food safety issues with linkages to Listeria outbreak and a recent Salmonella related recall. These were observed in ready-to-eat hummus and indicated the requirement of further processing. Conventional thermal processes might require longer times with negative impact on the quality due to the high viscosity of hummus with its solid-like rheology. For an efficient process design, microwave (MW) processing might be considered with its volumetric heating feature. Therefore, the objective of this study was to present MW application for a decontamination process for hummus. For this purpose, a computational model was developed to determine the temperature change during the process. This model was validated using the experimentally obtained temperature data from samples processed in polystyrene petri dishes (60 g – 8.5 cm in diameter and 1.2 cm in height) in a lab-scale MW system. Color changes were determined, and changes in its viscosity were used to understand the variation in the rheological attributes. Hummus samples were also inoculated with Salmonella cocktail to ≈7–8 log10 CFU/g prior to the MW process, and 70 W MW processing for 5 min (to average temperature of 95.3 °C) resulted in >4 log cycle reduction. Changes in color and rheological attributes were not significant with rather limited mass losses, and these indicated the possible MW processing for hummus decontamination with the need of designing an industrial scale processing.