Ultraviolet (UV‐C) radiation as a practical alternative to decontaminate thyme ( Thymus vulgaris L.)

Abstract

Alternative and cost‐effective decontamination methods for dehydrated herbs and spices are subject of interest in industry. In this work, a fluidized bed ultraviolet (UV‐C) system was tested for decontamination of dehydrated thyme. The samples were exposed to UV‐C radiation at 254 nm at 25.7, 51.4, 102.8, and 205.6 J/cm2 delivered at an intensity of 26.7 mW/cm2. UV‐C at 205.6 J/cm2 resulted in 1.8, 1.3, and 0.3 log cfu/g reductions in total aerobic mesophilic bacteria, total yeast/mold, and Bacillus cereus, respectively. Total phenolic content, total antioxidant activity, moisture content, and the sensory attributes were not affected by the UV‐C treatments. UV‐C caused a small increase in L* and a* values but these changes were not detected in sensory evaluation. In conclusion, UV‐C treatment up to 205.6 J/cm2 applied in a fluidized bed setting can potentially be used in decontamination of thyme without adverse effects on quality. Practical applications UV‐C radiation is a widely used effective technology to reduce the microbial load on various surfaces, liquids, and air environments. In this study, the potential of a fluidized bed UV system was explored to reduce natural microbial load of thyme. The results indicated that UV‐C application may be an effective technology for decreasing the microbial load of thyme without inducing significant changes to the physical, chemical, and sensorial quality, therefore it has a potential as an alternative method for decontamination of thyme and similar herbs and spices industrially.

Zn, Cu, and Fe Concentrations in Dehydrated Herbs (Thyme, Rosemary, Cloves, Oregano, and Basil) and the Correlation with the Microbial Counts of Listeria monocytogenes and Other Foodborne Pathogens

“…Ferriccioni et al [ 5 ] have indicated that dried thyme can be decontaminated before marketing and use by ultraviolet radiation treatment, which reduces the growth of aerobic mesophilic microorganisms, molds, and yeasts by more than 90%. Dogu-Baykut and Gunes [ 31 ] indicate that with this treatment, in addition to the microorganisms mentioned above, the development of B. cereus is also considerably reduced.…”

Effect of Argan oil, thyme, and rosemary on the drying process of Sardina Pilchardus fillets

“…The results obtained have led to an increase in the shelf life of sardine fillets marinated and dried on the basis of Argan oil and thyme, this period was estimated at more than six (6) months unlike the product with argan oil, rosemary, and without marinade that will be destroyed in a few weeks. The findings result be explained by the antioxidant activity of thyme caused by phenolic monoterpenes, thymol, and carvacrol, which are the major compounds found in thyme (Dogu‐Baykut & Gunes, 2019; Nateqi & Mirghazanfari, 2018).…”