Comparative Assessment of Non-Thermal Decontamination Technologies for Microbial Safety and Quality Preservation of Thyme (Thymus vulgaris L.)

Maintaining microbiological safety while preserving the phytochemical integrity of medicinal herbs, particularly thyme (Thymus vulgaris L.), represents a significant challenge for the pharmaceutical and food industries. Conventional thermal sterilization often compromises the volatile essential oils and antioxidant compounds, such as thymol and carvacrol, which define the commercial and therapeutic value of thyme. This study provides a comprehensive comparative assessment of three prominent non-thermal decontamination technologies gamma irradiation, electron beam irradiation, and various cold plasma treatments (hydrogen, nitrogen, argon, and X-ray plasma)—to determine their effectiveness in microbial reduction and quality preservation. Experimental results indicate that all non-thermal approaches significantly outperform conventional thermal methods in maintaining the phytochemical profile. Gamma and electron beam irradiation demonstrated superior microbial inactivation efficiency and penetration capability, making them highly suitable for large-scale industrial sterilization of bulk and packaged products. Conversely, cold plasma technology, specifically hydrogen plasma, offered an environmentally benign alternative with minimal thermal impact, providing a more refined approach for preserving heat-sensitive metabolites. The study establishes that the selection of an appropriate decontamination strategy is contingent upon a balanced consideration of the required microbial reduction threshold, the sensitivity of the product's functional properties, industrial throughput requirements, and environmental sustainability. These findings provide an evidence-based framework for manufacturers and regulatory authorities to optimize processing strategies for high-quality, export-oriented medicinal herbs.

کلیدواژه ها:

Thymus vulgaris L. ، Non-thermal Sterilization ، Gamma Irradiation ، Electron Beam ، Cold Atmospheric Plasma ، Microbial Decontamination ، Phytochemical Preservation ، Food Safety