Development of a novel microbiological method for detection of gamma irradiated spices

Abstract

Spices are food additives that are used in many different areas of food technology. Most of the spices contain essential oils sensitive to thermal degradation processes. Therefore, an alternate method of decontamination, other than thermal, should be used so that the microbial safety of the spices is ensured. This study was focused on the evaluation of the effect of ionizing radiation, known as radurization, on microbiological safety in samples of red pepper, black pepper, and stinging nettle, from North Macedonia. Samples were irradiated by 60Co γ-rays. The possibility for development of a novel, shortened microbiological method was investigated. The conventional agar plate method was used, as a standard microbiological method, in order to evaluate the effect of irradiation on the microbiological safety of the food. The red pepper and the stinging nettle did not show any microbial growth when inoculated on both growth media, after being irradiated. Additionally, the photostimulated luminescence and thermoluminescence method were used as physical methods. By comparing the two glow curves for the glow ratio, the obtained values are greater than 0.1, which confirms that the samples have been irradiated.

Keywords

• microorganisms
• decontamination
• irradiation
• food
• spices
• thermoluminescence