Effect of Low Temperature Cold Plasma Coupling Ultrasonic Technology on the Preservation Effect of Crucian Carp

Abstract

Background: Among China's freshwater fish, crucian carp produce is the highest. The creation of Crucian carp preservation techniques is crucial since the shelf life of fresh crucian carp can be as low as two days. The deterioration of crucian carp flesh may be caused by bacteria found in fresh crucian carp as well as additional microorganisms that develop during storage at normal temperatures. Low-temperature plasma is a frequently utilized technology because of its ability to be environmentally friendly and strong antibacterial capabilities. Plasma-activated water (PAW) combined with ultrasonics is a green technique for sanitizing pathogens in biotechnology. The goal of this study is to assess how well low-temperature plasma sterilization technology paired with modified atmosphere packing can disinfect water. Background: Crucian carp is the most produced freshwater fish in China. The development of crucian carp preservation techniques is essential because the shelf life of fresh crucian carp is as short as two days. The flesh of crucian carp can deteriorate due XI to bacteria found in fresh crucian carp, as well as additional microorganisms that develop during storage at normal temperatures. Low-temperature plasma is a frequently used technology because of its environmentally friendly properties and strong antibacterial capabilities. Plasma-activated water (PAW) combined with ultrasonics is a green technique for sanitizing pathogens in biotechnology. The goal of this study is to evaluate how well low-temperature plasma sterilization technology paired with modified atmosphere packing can disinfect water. Methods: Amplicon sequencing technology was used to examine the bacteria flora of fresh crucian carp which was maintained at room temperature for seven days. The approaches for bacterial reduction used ultrasonic-coupled plasma activation water treatment and modified atmosphere packaging coupling low-temperature plasma treatment. In this investigation, sterile activated water was prepared for 10 minutes using a maximum power of 100 watts. Fresh crucian carp flesh was placed in sterile activated water before being cleaned for 30 minutes with an ultrasonic cleaner (100 watts, 40 kHz). As a control group, it was kept at 4 °C after treatment. Methods: Amplicon sequencing technology was used to examine the bacterial flora of fresh crucian carp that was maintained at room temperature for seven days. Two approaches were used for bacterial reduction: ultrasonic-coupled plasma activation water treatment and modified atmosphere packaging coupling low-temperature plasma treatment. Sterile activated water was prepared for 10 minutes at a maximum power of 100 watts. Fresh crucian carp flesh was placed in sterile activated water for 30 minutes before being cleaned with an ultrasonic cleaner (100 watts, 40 kHz). A control group was kept at 4 °C after treatment. Results: The 16S rDNA detection of fresh crucian carp meat revealed 22 phyla, 31 classes, 67 orders, 126 families, 254 genera, and 332 species of bacteria. After 7 days of storage, 9 phyla, 14 classes, 27 orders, 52 families, 82 genera, and 286 species were detected, which decreased by 13 phyla, 17 classes, 40 orders, 74 families, 172 genera, and 48 species compared to fresh crucian carp meat. Proteus, Escherichia coli, Shigella, etc. are harmful bacteria. XII Results: The 16S rDNA detection of fresh crucian carp meat revealed the presence of 22 phyla, 31 classes, 67 orders, 126 families, 254 genera, and 332 species of bacteria. After 7 days of storage, the number of phyla, classes, orders, families, genera, and species decreased to 9, 14, 27, 52, 82, and 286, respectively. This represents a decrease of 13 phyla, 17 classes, 40 orders, 74 families, 172 genera, and 48 species compared to fresh crucian carp meat. Proteus, Escherichia coli, and Shigella are examples of harmful bacteria. The total number of colonies, coliforms, and psychrophilic bacteria in the treatment group were significantly lower than those in the control group; the flavor value of the treatment group during storage (0d12d) was closer to the original flavor of 0d than that of the control group; and the sensory evaluation score was obviously higher than that of the control group, indicating that treatment on the bacteria reduction of fresh crucian carp is obvious by the ultrasonic coupled plasma activation water. From the perspective of the total number of bacterial colonies, the shelf life can be extended by about 48 hours. It shows that ultrasonic-coupled plasma-activated water treatment is a safe and efficient preservation technology and has an obvious preservation effect on fresh crucian carp meat. The total number of colonies, coliforms, and psychrophilic bacteria in the treatment group were significantly lower than those in the control group. The flavor value of the treatment group during storage (0d-12d) was closer to the original flavor of 0d than that of the control group, and the sensory evaluation score was obviously higher than that of the control group. These results indicate that ultrasonic-coupled plasma-activated water treatment is effective in reducing the bacteria load in fresh crucian carp. From the perspective of the total number of bacterial colonies, the shelf life can be extended by about 48 hours. This shows that ultrasonic-coupled plasma-activated water treatment is a safe and efficient preservation technology with an obvious preservation effect on fresh crucian carp meat. Fresh crucian carp meat was packaged in a modified atmosphere with air, and plasma sterilization was performed for 5 minutes under the conditions of a high voltage discharge XIII voltage of 130 kV and a high voltage discharge frequency of 50 Hz. It was found that the total number of colonies in the treatment group decreased by 5.1%, 31%, 29.7%, and 15.9% compared with the control respectively at 2d, 4d, 6d, and 8d after treatment except for 0d under the storage condition of 4°C; the differences were all reached at a significant level, and the total number of colonies in the treatment group stably reached 6 log cfu/g until the 6th day after treatment, while the total number of colonies in the control group stably reached above 6.0 log cfu/g (7.28 log cfu/g) on the 2nd day, indicating that the high-voltage discharge under the conditions of voltage 130 kV and high-voltage discharge frequency 50 Hz, plasma sterilization treatment for 5 minutes can prolong the freshness period of fresh crucian carp meat by about 96 hours; E. coli colonies in the treatment group the 2d, 4d, 6d, and 8d after treatment were 7%, 48.3%, 53.2%, and 18.8% lower than the control group respectively except 0d, and the difference also reached a significant level; the psychrophilic bacteria colonies in the treatment group the 2d, 4d, 6d, and 8d after treatment were 2.9%, 23.7%, 18.1%, and 8.1% lower than the control group respectively except 0d, and the difference also reached a significant level; and the difference also reached a significant level. In each measurement result (0, 1, 2d), the odor of the modified atmosphere packaging coupled with the low-temperature plasma treatment group was closer to the original flavor of 0d than the control group, and the difference with the control group became more and more obvious with the increase in storage time. The sensory evaluation score was also obviously higher than that of the control group, indicating that the modified atmosphere packaging coupled with low-temperature plasma treatment had a good effect on the retention of volatile odor components. With the prolongation of storage time, the content of organic sulfides in the control group increased due to the increase in the bad smell of crucian carp, while modified atmosphere packaging coupled with low-temperature plasma sterilization treatment can significantly slow down the process due to inhibiting the growth of bacteria. Fresh crucian carp meat was packaged in a modified atmosphere with air and subjected to plasma sterilization for 5 minutes under the conditions of a high voltage discharge voltage of 130 kV and a high voltage discharge frequency of 50 Hz. The results showed that compared to the control group, the total number of colonies in the treated group decreased by 5.1%, 31%, 29.7%, and 15.9% at 2d, 4d, 6d, and 8d after treatment, XIV respectively, under the storage condition of 4°C. The total number of colonies in the treatment group stably reached 6 log cfu/g until the 6th day after treatment, while the control group consistently reached above 6.0 log cfu/g (7.28 log cfu/g) on the 2nd day. This indicates that the high-voltage discharge treatment at a voltage of 130 kV and a discharge frequency of 50 Hz for 5 minutes can extend the freshness period of fresh crucian carp meat by approximately 96 hours. The treatment group exhibited reductions of 7%, 48.3%, 53.2%, and 18.8% in E. coli colonies at 2d, 4d, 6d, and 8d after treatment, respectively, compared to the control group (except for 0d). These reductions were statistically significant. Similarly, for psychrophilic bacteria colonies, the treatment group showed decreases of 2.9%, 23.7%, 18.1%, and 8.1% at 2d, 4d, 6d, and 8d after treatment, respectively, in comparison to the control group (except for 0d). These differences were also statistically significant. In each measurement result (0, 1, 2d), the odor of the modified atmosphere packaging combined with low-temperature plasma treatment group closely resembled the original flavor of 0d, surpassing the similarity observed in the control group. As the storage time increased, the distinction between the treatment group and the control group became more pronounced. Furthermore, the sensory evaluation score was significantly higher in the treatment group compared to the control group, suggesting that the combination of modified atmosphere packaging and low-temperature plasma treatment effectively preserved volatile odor components. The content of organic sulfides in the control group increased with prolonged storage time, resulting in the intensification of bad odor in crucian carp. However, modified atmosphere packaging coupled with low-temperature plasma sterilization treatment can significantly slow down this process by inhibiting the growth of bacteria. Conclusion: Ultrasonic-coupled plasma-activated water and modified atmosphere packaging coupled with low-temperature plasma sterilization exhibited a good bactericidal effect, low cost, and no adverse effects after treatment, so they have good application prospects. Conclusion: The combination of ultrasonic-coupled plasma-activated water and modified atmosphere packaging, along with low-temperature plasma sterilization, demonstrated a favorable bactericidal effect, cost-effectiveness, and absence of adverse effects post-treatment. As a result, these methods hold promising application prospects.