Microbial Decontamination of Cuminum cyminum Seeds Using "Intensification of Vaporization by Decompression to the Vacuum": Effect on Color Parameters and Essential Oil Profile

Abstract

Cumin seeds are frequently utilized in herbal infusions and as flavoring agents in home cuisine. Nevertheless, studies have demonstrated that spices are frequently contaminated with pathogenic bacteria, including bacterial spores. The aim of this study was to assess the effectiveness of a new decontamination method called "Intensification of Vaporization by Decompression to the Vacuum" (IVDV) on intentionally contaminated Cuminum cyminum seeds. The study also examined the impact of this treatment on the color and oil profile of the treated samples. The untreated samples were inoculated with Escherichia coli (ATCC 25922) and Salmonella Typhimurium (ATCC 14028) and then subjected to IVDV treatment. Response surface methodology was employed to obtain safe, high-quality cumin seeds presenting a balance between microbial load, color, and oil profile. The optimal IVDV conditions were achieved at a pressure of 3.5 bar and a time of 133.45 s, resulting in typical 4 log reductions observed with 99.99% of Escherichia coli and Salmonella Typhimurium inactivation. The treated spices presented a mild color modification compared to the untreated ones, manifested by a darker shade (decreased L* value), reduced greenness (increased a* value), and heightened yellowness (increased b* value). The GC-MS analysis detected the existence of seven compounds in the treated cumin, with cuminaldehyde being the primary compound (83.79%). Furthermore, the use of IVDV treatment resulted in an increase in the total content of essential oils in some samples, whereby six monoterpenes were identified in the untreated sample compared to seven monoterpenes in IVDV-treated samples. This innovative technology demonstrated high efficacy in decontaminating C. cyminum seeds, improving the extractability of the essential oils while only slightly affecting the color.