## 3 Results and Discussion  
### Microbiogical Aspects  
Figure 1 illustrates the trend in the total colony count of the smoothie samples during storage. Total colony counts decreased by at least one order of magnitude with either treatment applied. In contrast, the total colony count values of the control (untreated) sample demonstrated an increasing trend during storage. After two weeks of storage, it was already deteriorating at 6 \({}^{\circ}\)C.  
Of the samples stored for two weeks, those subjected to the combined treatment had the best total bacterial counts. Storage at 6 \({}^{\circ}\)C caused little change in total colony counts, while samples stored at 15 \({}^{\circ}\)C had total colony counts more than two orders of magnitude higher than those tested on day 0 but still below 10\({}^{4}\) CFU/mL. The total colony counts of samples treated with the combined treatments and stored at 6 \({}^{\circ}\)C for 14 days were slightly lower than those of fresh samples. This reduction can be attributed to the enhanced preservative effect of the combination of mild heat and HHP treatment together with low storage temperatures (hurdle technology, [52]). According to the hurdle technology, microorganisms have to overcome more preservation factors as hurdles in order to multiply. Storage at 15 \({}^{\circ}\)C in combination with the treatments used did not provide an adequate preservative effect. In samples that had been subjected to a single treatment, a significant increase in total colony count was observed after two weeks of storage at 6 \({}^{\circ}\)C. However, after two weeks of storage at 15 \({}^{\circ}\)C, the sample treated at 250 MPa exhibited signs of deterioration. The sample that was treated at 60 \({}^{\circ}\)C showed signs of spoilage after two weeks of storage at 15 \({}^{\circ}\)C.  
Our results are consistent with those of [PERSON] et al. [53], who treated pomeranguiuce at 200 MPa for 5 min. The reduction in microbial counts compared to the untreated control in their study was 1.2-1.7-log CFU/mL, whereas our results showed a reduction of 1.1-log CFU/mL. Figure 1: Total colony count of smoothie samples. A, B: comparison of fresh samples treated with different methods ([PERSON]’s post hoc test, \(p\) < 0.05); a, b, c: comparison of samples stored at 6 \({}^{\circ}\)C for 14 days and treated by different methods ([PERSON]’s post hoc test, \(p\) < 0.05); **, ***, ***: comparison of samples stored at 15 \({}^{\circ}\)C for 14 days and treated by different methods ([PERSON]’s post hoc test, \(p\) < 0.05). A comparison of fresh samples treated differently revealed significant differences between the control sample and the others. A similar result was observed when comparing samples stored at 6 \({}^{\circ}\)C, with the control sample differing from the others. In this case, both the single and combined treated samples were distinguishable. When comparing the results of the samples stored at 15 \({}^{\circ}\)C, no significant difference was found between the control and the 250 MPa treated samples or between the two combined treated samples. However, the control and 250 MPa treated samples and the combined treated samples exhibited a significant difference from each other, as well as from the sample treated at 60 \({}^{\circ}\)C. The non-thermal treatment was found to be ineffective in maintaining low microbial counts when storage temperatures were higher (15 \({}^{\circ}\)C) compared to the expected low value (6 \({}^{\circ}\)C). The additional thermal treatment was therefore required to ensure the desired microbial count during storage at 15 \({}^{\circ}\)C.  
The total colony count of the samples was not affected by the order of treatments. The microbiological results indicated that storage at 15 \({}^{\circ}\)C did not produce an acceptable level of microbiological quality. Similarly, treatments at 60 \({}^{\circ}\)C for 5 min and at 250 MPa for 5 min alone resulted in a significant increase in total colony counts.