## 3 Results and Discussion  
### Viable Organism Content of Tarhana Samples during Storage  
In all irradiation doses applied, the formation of pests in tarhana samples could be prevented. However, in the control group without irradiation, a significant number of pests were found (Figure 1a). These results showed that irradiation was effective at preventing pest formation. The major problem for dried tarhana during storage is pest formation, which is a spontaneous biological problem due to the development of larval eggs over time if the tarhana is stored under unsuitable conditions with high moisture and temperature. This problem is recognized to cause economic losses for many dried foods [3]. In this study, to test the effectiveness of irradiation, irradiated and control tarhana samples were observed at a constant high temperature (25 \({}^{\circ}\)C). Normally, it is advised that tarhana should be stored under 20 \({}^{\circ}\)C with low humidity [2, 6].  
The irradiation widely and distinctly reduced the microbial load. However, microbiological activity increased with extended storage time dependent on the irradiation dose applied, meaning that higher doses retarded the microbial growth for longer. The TAMB amounts of tarhana samples were closely related with the applied irradiation dose. The TAMB content at approximately 7 log CFU/gr for control samples was reduced substantially after irradiation (Figure 1b). However, the TAMB amounts significantly increased during storage (p \(<\) 0.05) for the 2.5 and 5 kGy irradiated tarhana samples. In 10 kGy irradiated samples, the TAMB counts remained below 1 log CFU/gr until the fifth month of storage. Similarly, the yeast mold content of tarhana samples was considerably reduced at all irradiation doses. Only the 2.5 kGy irradiated sample remained above 1 log CFU/gr. Although the yeast mold content of the 2.5 kGy tarhana sample reached the same level as the control group at the end of storage (p \(>\) 0.05), the amount of yeast mold remained below 3 log CFU/gr for the 5 kGy irradiated tarhana sample. The lowest amount of yeast mold was found in the 10 kGy irradiated sample (Figure 1c). After irradiation, the _Bacillus cereus_ (BC) content was able to be reduced below 1 log CFU/gr at all doses applied. For the control tarhana sample, the BC content reached 5 log CFU/gr after 5 months. However, the BC content increased above 1 log CFU/gr after the first month of storage for both 2.5 and 5 kGy irradiated samples as well as after the third month of storage for the 10 kGy irradiated sample; however, the BC content was significantly below 2.5 log CFU/for at both irradiated tarhana samples (Figure 1d). These results indicate that irradiation is important for ensuring microbiological safety in tarhana. In addition, while a similar level of microbiological protection was provided in tarhana at 2.5 and 5 kGy doses, more effective protection was achieved in the 10 kGy irradiated tarhana sample. The effectiveness of irradiation is related with the microbial load of foods [9, 11]. Indeed, tarhana is a fermented food which includes substantial amounts of lactic acid bacteria and yeast, although some of this flora are reduced during drying [1, 2]. However, some spore-forming bacteria and molds could be contaminated according to the traditional drying conditions [6, 7, 8]. These microbiological results suggested that a minimum 5 kGy dose is required to eliminate the majority of fermenting and contaminating flora in dried tarhana.  
Figure 1: Cont.