生鲜肉类如猪肉由于丰富的水分和营养极易受到微生物的污染而导致腐败变质。常见的腐败菌中，假单胞菌（Pseudomonas spp.）是一类嗜冷菌，能够在低温贮藏的猪肉中生长繁殖。冰温保鲜比冷藏保鲜的贮藏温度更低，可在一定程度上缓解低温贮藏中的腐败进程。然而假单胞菌仍能在冰鲜猪肉中进行生命活动，影响其品质和货架期。目前，肉类行业常用的非热保鲜方式包括微波杀菌技术、电离辐射处理、超高压处理、低温等离子体和紫外杀菌技术等。这些技术不仅对细菌灭活十分有效，且相比传统的热杀菌能在处理过程中保留肉的风味。然而单一保鲜技术也有相应的局限性，包括技术覆盖面有限、效率不足等。物理场之间的协同组合技术可通过不同物理场的能量耦合与效应互补，实现"1+1>2"的杀菌效果，成为当前非热杀菌领域的研究热点。本研究选择表面介质阻挡放电（SDBD）低温等离子体与222 nm紫外（UV）杀菌技术的联合应用处理莓实假单胞菌P. fragi和冰鲜猪肉，并研究组合技术对假单胞菌的消杀效果及其在冰鲜猪肉保鲜中的应用。

主要研究结果如下：

（1）首先通过单因素试验研究SDBD+UV处理时间、照射距离和保留时间对莓实假单胞菌P. fragi菌落数的影响，结果表明P. fragi菌落数随SDBD+UV处理时间的延长而降低，随保留时间的延长而降低，随照射距离的增加而升高但在12 ~ 18cm处变化不显著。然后通过响应面试验优化了SDBD+UV处理P. fragi的工艺参数，发现照射距离和保留时间的交互作用显著，并确定了最佳处理条件：处理时间150 s，照射距离16.4 cm，保留时间120 s。在此条件下进行体外杀菌试验，P. fragi数量从8.46 Log CFU/mL减少至2.11 Log CFU/mL，杀菌率达到99.9999%。

（2）分别从细胞结构及胞内分子水平研究SDBD+UV协同抗菌机制。SDBD+UV处理的光学发射光谱特征显示SDBD与UV特征峰共存，证实两者物理过程的协同整合效应。SDBD 的发射光谱主要由氮发射、OH发射和Hα发射为主，UV发射峰主要以222 nm的远紫外峰为特征。SDBD+UV处理通过破坏P. fragi细胞膜完整性和细胞形态结构，显著提升细胞膜通透性，引发细胞膜脂质过氧化及胞内生物大分子/钾离子泄漏；同时在分子层面触发等离子体诱导的氧化应激，促使胞内ROS水平激增，通过抑制超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性瓦解细菌抗氧化防御体系，最终借助胞外物理破坏与胞内氧化损伤的协同作用实现高效灭菌。

（3）研究SDBD+UV处理对冰鲜猪肉的保鲜效果。结果表明，SDBD+UV处理能够显著降低猪肉中的菌落总数和假单胞菌数量，与空白对照相比，猪肉初始菌落总数和假单胞菌分别下降1.03 Log CFU/g和0.90 Log CFU/g；延缓pH值、挥发性盐基氮（TVB-N）、硫代巴比妥酸值（TBA）和过氧化值（POV）的升高，能够保持猪肉较好的色泽和水分含量，到冰温贮藏期的第12天时菌落总数、假单胞菌数、TVB-N和TBA值分别为6.28 Log CFU/g、4.31 Log CFU/g、23.01 mg/100g和1.44 mg MDA/kg，均显著低于对照、SDBD和UV单独处理组。SDBD+UV处理组猪肉在冰温贮藏期的第9天仍未变质，货架期在6天的基础上延长3天。上述结果表明，SDBD+UV处理是一种高效、环保且对肉品品质影响较小的保鲜技术，具有广阔的应用前景。

Fresh meat, such as pork, is highly susceptible to microbial contamination and spoilage due to its rich moisture and nutrients. Among the common spoilage bacteria, Pseudomonas spp. are psychrophilic bacteria that can grow and reproduce in chilled pork. Ice-cold preservation, which has a lower storage temperature than refrigeration, can to some extent slow down the spoilage process in low-temperature storage. However, Pseudomonas spp. can still carry out metabolic activities in chilled pork, affecting its quality and shelf life. At present, non-thermal preservation methods commonly used in the meat industry include microwave sterilization, ionizing radiation treatment, high-pressure processing, low-temperature plasma, and ultraviolet sterilization. These technologies are not only highly effective in inactivating bacteria but also, compared with traditional thermal sterilization, can retain the flavor of meat during processing. However, each single preservation technology also has its limitations, such as limited coverage and insufficient efficiency. The synergistic combination of different physical fields, through the coupling of energy from various physical fields and complementary effects, can achieve a sterilization effect where "1 + 1 > 2" and has become a research hotspot in the field of non-thermal sterilization. This study selected the combined application of surface dielectric barrier discharge (SDBD) low-temperature plasma and 222 nm ultraviolet (UV) sterilization technology to treat Pseudomonas spp. and chilled pork, and investigated the bactericidal effect of the combined technology on Pseudomonas fragi (P. fragi) and its application in the preservation of chilled pork.The main research results are as follows:

(1) First, single-factor experiments were conducted to study the effects of SDBD + UV treatment time, irradiation distance, and retention time on the colony count of P. fragi. The results showed that the colony count of P. fragi decreased with the extension of SDBD + UV treatment time and retention time, and increased with the increase of irradiation distance, but there was no significant change between 12 and 18 cm. Then, response surface experiments were used to optimize the process parameters of SDBD + UV treatment of P. fragi. It was found that the interaction between irradiation distance and retention time was significant, and the optimal treatment conditions were determined: treatment time of 150 s, irradiation distance of 16.4 cm, and retention time of 120 s. Under these conditions, an in vitro sterilization experiment was carried out, and the number of P. fragi decreased from 8.46 Log CFU/mL to 2.11 Log CFU/mL, with a sterilization rate of 99.9999%.

(2) The synergistic antimicrobial mechanism of SDBD+UV was studied at both the cellular structure and intracellular molecular levels. The optical emission spectra of SDBD+UV treatment showed the coexistence of characteristic peaks of SDBD and UV, confirming the synergistic integration effect of the two physical processes. The emission spectrum of SDBD was mainly characterized by nitrogen emission, OH emission, and Hα emission, while the UV emission peak was characterized by a far-ultraviolet peak at 222 nm. SDBD+UV treatment disrupted the integrity of the P. fragi cell membrane and the cellular morphological structure, significantly increased cell membrane permeability, induced lipid peroxidation of the cell membrane, and caused leakage of intracellular biomacromolecules and potassium ions. At the molecular level, it triggered plasma-induced oxidative stress, leading to a sharp increase in intracellular reactive oxygen species (ROS) levels. By inhibiting the activities of superoxide dismutase (SOD) and catalase (CAT), it dismantled the bacterial antioxidant defense system. Ultimately, it achieved efficient sterilization through the synergistic action of extracellular physical disruption and intracellular oxidative damage.

(3) The study investigated the preservation effect of SDBD+UV treatment on chilled pork. The results showed that SDBD+UV treatment could significantly reduce the total bacterial count and the number of Pseudomonas spp. in pork. Compared with the blank control, the initial total bacterial count and Pseudomonas spp. count in pork decreased by 1.03 Log CFU/g and 0.90 Log CFU/g, respectively. It also delayed the increase of pH value, total volatile basic nitrogen (TVB-N), thiobarbituric acid value (TBA), and peroxide value (POV), and maintained better color and moisture content of the pork. On the 12th day of ice-cold storage, the total bacterial count, Pseudomonas spp. count, TVB-N, and TBA values were 6.28 Log CFU/g, 4.31 Log CFU/g, 23.01 mg/100g, and 1.44 mg MDA/kg, respectively, all of which were significantly lower than those of the control, SDBD, and UV single treatment groups. The pork in the SDBD+UV treatment group remained unspoiled on the 9th day of ice-cold storage, extending the shelf life by 3 days compared to the original 6 days. The above results indicate that SDBD+UV treatment is an efficient, environmentally friendly, and less impactful preservation technology on meat quality, with broad application prospects.