## 4 Conclusions  
This paper presents the determination and identification of the critical quality parameters for fresh peaches and nectarines in cold chain logistics implemented by the real-time monitoring of temperature, relative humidity, and CO\({}_{2}\) fluctuation. The implementation comprises the use of the implemented WSN nodes, and their effect on fresh peach and nectarine fruits, in order to improve the cold chain management as well as provide the sustainability of fresh peach fruit cold chain logistics.  
The environmental fluctuation analysis for cold chain demonstrates the temperature, relative humidity, and CO\({}_{2}\) characteristics in the fresh peaches and nectarine cold chain logistics. The identification of dramatic changes provides an early warning for the need to take effective measures in advance and resolve any problems that may cause unexpected quality loss.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & **Average Weight** & **Initial** & **Final** & **Firmness Decline** & **Initial** & **Final** & **SSC Decline** \\  & **Loss (\%)** & **Firmness** & **Firmness** & **Rate (\%)**\({}^{\text{x}}\) & **SSC** & **SSC** & **Rate (\%)**\({}^{\text{x}}\) \\ \hline nectarine control & 1.86 b & 3.59 ab & 2.47 ab & 31.20 & 9.23 a & 8.21 a & 11.06 \\ nectarine red net & 2.18 ab & 3.85 a & 2.21 b & 42.60 & 9.20 a & 8.45 a & 8.15 \\ peach control & 2.43 ab & 2.99 bc & 2.61 a & 12.71 & 8.50 ab & 8.3 a & 2.35 \\ peach red net & 2.89 a & 2.94 c & 2.29 ab & 22.07 & 8.27 b & 8.1 a & 2.06 \\ \hline \hline \end{tabular} Note: Values inside column followed by the same letter are not statistically significant according to LSD (Least Significant Difference) test at \(p\leq 0.05\) level; \({}^{\text{x}}\)—statistical analysis was not performed.  
\end{table}
Table 3: The quality of peaches and nectarines in the experimental fresh peach and nectarine chain.  
Several quality parameters for cold chain, such as weight loss, firmness, and SSC can be used to describe the quality change of fresh peaches and provide a comprehensive assessment of fruit quality in general. In this study, the weight of the peaches and nectarines, as well as their firmness and SSC, was largely decreased during the short chain. The quality data suggest that nectarine fruit is more prone to postharvest quality deterioration than peach fruit. Therefore, postharvest cold chain of nectarines must be more precisely monitored and controlled to preserve fruit quality.  
The results of this study provide some theoretical basis for the assessment of the fresh peach fruit quality in cold chain logistics, which can be used by producers and distributors in the further planning of their cold chain logistics in order to maintain a good economic value of their products.  
This work was supported by DBN Young Scholars Research Program and the National Key Research and Development Program of China (2016 YFD0400901). This experiment was done in Croatia during a visit by the first author that was supported by the Chinese-Croatian bilateral Scientific and Technological Cooperation Programme (7-1).  
[PERSON] and [PERSON] conceived and designed the experiments, they made the same contributions. [PERSON] and [PERSON] performed the experiments. [PERSON] and [PERSON] analyzed the data. [PERSON] contributed materials/analysis tools. [PERSON] wrote the paper. [PERSON], [PERSON] and [PERSON] contributed to the paper's modification and refinement.  
The authors declare no conflict of interest.  
The proposed method could be adapted into other fruits postharvest quality monitoring and traceability applications.