流式细胞术在超高压诱导大肠杆菌O157:H7亚致死研究中的应用

超高压作为一种应用日趋广泛的食品非热杀菌技术,对食源性大肠杆菌O157:H7有显著的致死作用,但对 其致死效应缺乏快速有效的评价手段,对其致死机制也需进一步证实。本研究运用流式细胞术结合传统培养方法, 评价了超高压对大肠杆菌O157:H7的致死效应,并通过扫描和透射电子显微镜技术观察分析了超高压处理后菌体细 胞微观结构的变化,初步探讨了超高压对大肠杆菌O157:H7的致死机制。结果表明：双染色流式细胞术检测方法能 够快速准确地对超高压处理后不同生理状态的大肠杆菌O157:H7细胞进行分析和分选,且具有较高灵敏度和精确 度;400 MPa的超高压处理对大肠杆菌O157:H7有明显的损伤和致死效果,菌体细胞出现严重变形,部分细胞的细 胞膜出现破裂;500 MPa处理时,致死效应更加明显,菌体细胞壁和细胞质膜严重分离,光透明区出现大量辐射丝 状物。菌体细胞膜完整性丧失很可能是超高压诱导大肠杆菌O157:H7致死的主要原因,即使经过500 MPa的超高压 处理,依然有不少大肠杆菌O157:H7菌体细胞处于亚致死状态,这部分亚致死状态的细菌是食源性疾病爆发的潜在 隐患。     

LED蓝光与柠檬酸对大肠杆菌的协同抗菌作用

为了开发新型食品抗菌方法,研究了LED蓝光辐照强度、柠檬酸质量浓度和温度3个因素对营养肉汤中大肠杆菌O157:H7抗菌性能的影响。结果表明:LED蓝光在低温(12℃)下对大肠杆菌O157:H7的抗菌效果优于室温(25℃),且抗菌效果随着光照剂量的增加而增强;柠檬酸在低温下对大肠杆菌O157:H7的影响较弱,但在室温下可明显减缓其生长速率;与空白对照组相比,在使用4 072.3J/cm~2光照剂量的LED蓝光照射后,大肠杆菌O157:H7的数量在低温下可减少(2.60±0.19)lg CFU/mL,而在室温下仅减少(0.67±0.12)lg CFU/mL;加入柠檬酸后,显著增强了LED蓝光的抗菌效果,在使用2 471.0J/cm~2光照剂量的LED蓝光照射后,大肠杆菌O157:H7的数量在低温下可减少(5.13±0.11)lg CFU/mL,在室温下可减少(3.08±0.11)lg CFU/mL。     

等离子体活化水-苯乳酸协同杀灭大肠杆菌O157:H7作用及机制研究

拟研究等离子体活化水（Plasma-activated water,PAW）与苯乳酸（Phenyllactic acid,PLA）协同处理对大肠杆菌O157:H7的杀灭效果及其作用机制。采用平板计数、扫描电镜、荧光染色等方法研究PAW与PLA协同处理对大肠杆菌O157:H7的杀灭作用及其对细胞形态、细胞膜完整性和胞内活性氧水平等的影响。结果表明,经终浓度为0.125～1.0 mg/mL的PLA处理8 min后,大肠杆菌O157:H7活细胞数未发生显著变化（P>0.05）。经PAW与PLA（终浓度为1.0 mg/mL）协同处理8 min后,大肠杆菌O157:H7降低了5.65 lg CFU/mL,显著高于PAW单独处理组（降低了1.06 lg CFU/mL） （P<0.05）。扫描电镜结果表明,PAW与PLA协同处理可造成细胞形态发生明显变化。与对照组细胞相比,经PAW-PLA（1.0 mg/mL）协同处理8 min后,胞外蛋白含量、细胞膜电位和胞内活性氧分别升高了25.6、0.75和9.53倍（P<0.05）。综上所述,PAW与PLA协同处理能够有效杀灭大肠杆菌O157:H7,这可能与其破坏细胞膜及诱导氧化损伤等有关。本研究为PAW与PLA协同处理在食品保鲜中的应用提供了理论依据。     

臭氧水与副干酪乳杆菌Z21联合处理对绿豆芽中大肠杆菌O157:H7的抑制机制

为研究臭氧水联合副干酪乳杆菌Z21发酵上清液对绿豆芽中大肠杆菌O157:H7的杀菌效果、细胞结构影响和生物膜清除作用,本实验对人工污染大肠杆菌O157:H7的绿豆芽进行联合处理,选出最优的杀菌条件,采用流式细胞仪、扫描电镜、傅里叶红外光谱（Fourier-transform infrared spectroscopy,FT-IR）、拉曼光谱分析臭氧水联合Z21发酵上清液的杀菌机制;通过菌落计数及胞外聚合物分析,研究了臭氧水联合Z21发酵上清液对大肠杆菌O157:H7生物膜的清除效果。结果表明,1.5 mg/L臭氧水联合10%（v/v）Z21发酵上清液处理对大肠杆菌O157:H7杀菌效果最佳,菌落总数减少了2.81 lg CFU/g;与对照组相比,联合处理破坏了大肠杆菌O157:H7细胞壁和细胞膜中的多糖,脂质和蛋白质结构,增加了细胞膜的通透性,改变了菌体形态。联合处理对生物膜有良好的清除效果,显著降低了生物膜的胞外聚合物含量（P<0.05）。本研究为大肠杆菌生物膜的清除及农产品防腐保鲜提供了理论依据。     

ε-聚赖氨酸对大肠杆菌O157:H7和金黄色葡萄球菌的抗菌稳定性

大肠杆菌O157:H7和金黄色葡萄球菌是常见的引起食物中毒的食源性致病菌,ε-聚赖氨酸(ε-PL)是一种安全、无毒、天然的食品防腐剂。食品的加工温度、pH值、金属离子是影响食品品质的三大要素。研究ε-PL在不同的温度、p H值、金属离子条件下,对食源性病原菌的杀菌稳定性,是指导ε-PL应用防治此类食源性致病菌的理论基础。结果表明:ε-PL对大肠杆菌O157:H7和金黄色葡萄球菌的最小抑菌质量浓度均为2.60 mg/mL。在4～121℃下,ε-PL抗菌活性不受温度影响,抑菌效果稳定,对大肠杆菌O157:H7和金黄色葡萄球菌有良好的抑菌效果。当p H值为4～6时,ε-PL对大肠杆菌O157:H7和金黄色葡萄球菌的抑菌效果最佳。Mn~(2+)、Zn~(2+)与LYS具有较高的协同作用;Mg~(2+)在很大程度上消除了ε-PL的抑菌效果,且呈剂量效应关系。     

不同非热加工技术对百香果果浆杀菌效果及品质变化的比较

为评价不同非热杀菌方式对果蔬原料杀菌效果及品质的影响,该研究分别采用超高压技术（High Hydrostatic Pressure,HHP）、低温等离子体技术（Cold Plasma,CP）和辐照技术三种方式对百香果鲜榨果浆进行杀菌处理。结果表明,三种非热处理方式对果浆中的微生物（2.15 lg(CFU/g)、2.44 lg(CFU/g)、2.34 lg(CFU/g)）均有一定的抑制和杀灭作用,其中300 MPa及以上压力处理和3 kGy辐照量处理后果浆的菌落数均＜1 lg(CFU/g),这两种方式对百香果果浆均有较好的杀菌效果。为了进一步探究超高压处理对果浆贮藏期的影响,该研究还探讨了超高压处理前后的果浆在-20 ℃的条件下储存9个月内微生物含量的变化,实验得出,500 MPa和600 MPa处理的百香果果浆在-20 ℃下储存9个月后微生物含量仍＜2 lg(CFU/g),符合国家安全规定。在理化性质方面,超高压技术和低温等离子体技术能有效保持果浆的色泽（ΔE＜2）和风味（p＞0.05）,且能抑制果浆POD酶、PPO酶的活性,但辐照处理无法钝化PPO酶。综上所述,超高压技术能有效杀灭百香果果浆中的菌落,并能更好地保持果浆的品质,因此超高压技术在百香果果浆中具有较好的商业应用前景。     

超高压对副溶血弧菌细胞壁膜损伤的研究

目的:研究超高压处理对副溶血弧菌细胞壁膜的损伤效应。方法:以副溶血弧菌为对象,探讨不同压力和保压时间对其存活量的影响,分析超高压处理对其细胞壁膜超微结构,细胞膜的通透性、流动性和Na+/K+-ATP酶活性,细胞壁特性以及细胞表面电位的影响。结果:研究表明,20℃经200MPa压力作用10min,副溶血弧菌致死率为100%。超高压处理会对副溶血弧菌细胞壁膜形态结构造成明显的损伤,细胞壁局部破坏,出现缺口;细胞结构不完整,细胞膜消失;细胞壁膜的损伤,使得胞质内含物出现泄漏。超高压处理使副溶血弧菌细胞膜通透性异常增加,膜流动性的显著下降,细胞膜Na+/K+-ATP酶活性降低以及细胞壁特性的改变。高于200MPa压力后,细胞表面zeta电位值随压力的增大而趋向稳定,细胞表面粒子完全絮凝,说明细胞结构已被高压破坏。结论:超高压处理对副溶血弧菌细胞壁膜形态结构造成明显的损伤,改变细胞膜和细胞壁的结构与特性,最终导致其胞内容物和无机盐外漏而致死。     

基于实时荧光环介导等温扩增快速检测鸡肉中的大肠杆菌O157:H

以大肠杆菌O157:H7的VT2基因序列设计特异性引物,利用Midori Green新型核酸荧光染料,建立鸡肉中大肠杆菌O157:H7实时荧光定量环介导等温扩增(Rti-LAMP)检测方法。纯培养大肠杆菌O157:H7检测灵敏度达3.5 CFU/反应,需时45 min。模拟大肠杆菌O157:H7污染鸡肉样品,经37℃增菌4 h,用Whirl-pak无菌袋过滤离心得沉淀,提取样品DNA模板用于Rti-LAMP反应,检测大肠杆菌O157:H7灵敏度达140 CFU/g,整个检测流程约7 h。采用蒙脱石封闭的活性炭前处理污染鸡肉样品,不经增菌过程,结果表明:该Rti-LAMP检测方法灵敏度达12 CFU/g,整个检测耗时约4.5 h。市购鸡肉样品51份,以大肠杆菌国标检测法为对照,研究基于Rti-LAMP联合增菌或封闭活性炭预处理而不经增菌的两种方法,对比检测临床鸡肉样品大肠杆菌O157:H7污染率。结果:国标法和增菌的Rti-LAMP两种方法均检测到同一鸡肉样品为大肠杆菌O157:H7阳性,经封闭活性炭预处理而未经增菌的Rti-LAMP则检测到8份鸡肉样品大肠杆菌O157:H7阳性。研究表明,封闭活性炭预处理的Rti-LAMP检测方法较国标法更灵敏、快速、简便、特异地检测鸡肉中大肠杆菌O157:H7污染。     

贮藏于4℃的家制酸奶中低浓度大肠杆菌O157:H7的存活研究

牛奶预热后分装并分别接种体积分数3%的酸奶和2.15(lg(CFU/mL))的大肠杆菌O157:H7,在45℃下发酵5h后贮藏于4℃的冰箱中。利用Pathatrix大体积循环系统中偶联了抗体的免疫磁珠特异性地捕获这些酸奶中的大肠杆菌O157:H7。免疫磁珠重悬于1%的蛋白胨水后涂布于添加了新生霉素(5mg/L)的山梨醇麦康凯固体培养基中,培养基在37℃恒温培养箱中放置24h。实验结果表明,酸奶中大肠杆菌O157:H7的数量逐渐减少,12d后才检测不到。因此乳制品加工及保存过程中,需要加强对大肠杆菌O157:H7污染的监测,以保证乳制品的安全性。     

超高压对鳙鱼肌动球蛋白物化特性的影响

研究不同超高压条件(100、300、500 MPa,保压15、30、45 min)下鳙鱼肌动球蛋白物化特性的改变。结果表明,随着压力和时间的增加,鳙鱼肌动球蛋白的溶解度降低,浊度基本呈上升的趋势,表明肌动球蛋白发生了聚集变性。SDS-PAGE显示超高压引起肌动球蛋白发生交联聚集形成了大分子物质。超高压处理后鳙鱼的Ca~(2+)-ATP酶(Ca~(2+)-ATPase)活性消失,表明肌动球蛋白发生了变性。随着压力的增加和加压时间的延长,肌动球蛋白的表面疏水性增加,表明超高压使蛋白氨基酸的疏水性基团暴露。随着压力的增大,肌动球蛋白的总巯基含量减少,二硫键含量升高,表明肌动球蛋白中的巯基发生氧化,形成了二硫键。鳙鱼肌动球蛋白上述物化特性的改变证明超高压诱导使其构象发生了改变。     

Potential application of high hydrostatic pressure to eliminate Escherichia coli O157:H7 on alfalfa sprouted seeds

Sprouts eaten raw are increasingly being perceived as hazardous foods as they have been implicated in Escherichia coli O157:H7 outbreaks where the seeds were found to be the likely source of contamination. The objective of our study was to evaluate the potential of using high hydrostatic pressure (HHP) technology for alfalfa seed decontamination. Alfalfa seeds inoculated with a cocktail of five strains of E. coli O157:H7 were subjected to pressures of 500 and 600 MPa for 2 min at 20 degrees C in a dry or wet (immersed in water) state. Immersing seeds in water during pressurization considerably enhanced inactivation of E. coli O157:H7 achieving reductions of 3.5 log and 5.7 log at 500 and 600 MPa, respectively. When dry seeds were pressurized, both pressure levels reduced the counts by <0.7 log. To test the efficacy of HHP to completely decontaminate seeds whilst meeting the FDA requirement of 5 log reductions, seeds inoculated with a ~5 log CFU/g of E. coli O157:H7 were pressure-treated at 600 and 650 MPa at 20 degrees C for holding times of 2 to 20 min. A >5 log reduction in the population was achieved when 600 MPa was applied for durations of > or =6 min although survivors were still detected by enrichment. When the pressure was stepped up to 650 MPa, the threshold time required to achieve complete elimination was 15 min. Un-inoculated seeds pressure-treated at 650 MPa for 15 min at 20 degrees C successfully sprouted achieving a germination rate identical to untreated seeds after eight days of sprouting. These results therefore demonstrate the promising application of HHP on alfalfa seeds to eliminate the risk of E. coli O157:H7 infections associated with consumption of raw alfalfa sprouts.     

Fate of Escherichia coli strains inoculated in model cheese elaborated with or without starter and treated by high hydrostatic pressure

The aim of this research was to study high hydrostatic pressure inactivation of two strains of Escherichia coli (E. coli O59:H21 [CECT 405] and E. coli O157:H7 [CECT 5947]) inoculated in washed-curd model cheese elaborated with and without starter and the ability of these strains for survival, recovery, and growth. Samples were treated at 300, 400, and 500 MPa for 10 min at 20 degrees C and analyzed after the treatment and after 1, 7, and 15 days of storage at 8 degrees C to study the behavior of Escherichia populations. Cheeses elaborated with starter showed the maximum lethality at 400 and 500 MPa, and no significant differences in the baroresistant behavior of either strains were detected, except for E. coli O157:H7 at 400 MPa in cell counts obtained with thin agar layer method medium, where the decrease value was significantly lower. In cheese elaborated without starter, the highest decrease value was observed at 500 MPa, except for E. coli O59:H21 in cell counts obtained with selective culture medium, where the highest decrease value was also found at 400 MPa. The ability to repair and grow was not observed in model cheese elaborated with starter, as cell counts of treated samples decreased after 15 days of storage at 8 degrees C. By contrast, in cheese elaborated without starter, all pressurized samples showed the trend to repair and grow during the storage period in both strains. These results suggest that the presence of starter and low pH values are the main factors that control the ability of Escherichia strains inoculated in this type of cheese and treated by high hydrostatic pressure to recover and grow.     

Membrane damage and enzyme inactivation of Lactobacillus plantarum by high pressure CO2 treatment

Physiological changes of Lactobacillus plantarum (KFRI 815) by high pressure CO2 treatment were investigated to examine the relevance to microbial inactivation. Characteristic properties of the cells measured in this study included salt tolerance, release of UV-absorbing substances, Mg and K ions, proton permeability, glycolysis, H+-ATPase and constitutive enzymes, and dye uptake. The cells treated with high pressure CO2 of 7 MPa at 30 degrees C for 10 min showed the irreversible cellular membrane damages including loss of salt tolerance, leakage of UV-absorbing substances, release of intracellular ions, collapse of proton permeability and uptake of Phloxine B dye. L. plantarum cells after CO2 treatment also exhibited reduced glycolytic activity and inactivation of some constituent enzymes. However, H+-ATPase of the cell membrane maintained its initial specific activity of about 2.50 U/mg protein even though viability of the cells was reduced by several log cycles after high pressure CO2 treatment.     

Inactivation of foodborne pathogens in milk using dynamic high pressure

Improving the microbiological safety of perishable foods is currently a major preoccupation in the food industry. The aim of this study was to investigate the inactivation of three major food pathogens (Listeria monocytogenes [LSD 105-1], Escherichia coli O157:H7 [ATCC 35150], and Salmonella enterica serotype Enteritidis ATCC [13047]) by dynamic high pressure (DHP) in order to evaluate its potential as a new alternative for the cold pasteurization of milk. The effectiveness of DHP treatment against L. monocYtogenes, E. coli O157:H7, and Salmonella Enteritidis was first evaluated in 0.01 M phosphate-buffered saline (PBS) at pH 7.2 as a function of applied pressure (100, 200, and 300 MPa) and of the number of passes (1, 3, and 5) at 25 degrees C. A single pass at 100 MPa produced no significant inactivation of the three pathogens, while increasing the pressure up to 300 MPa or the number of passes to five increased inactivation. From an initial count of 8.3 log CFU/ml, complete inactivation of viable L. monocytogenes was achieved after three successive passes at 300 MPa, while 200-MPa treatments with three and five passes completely eliminated viable Salmonella Enteritidis and E. coli O157:H7, respectively. The effectiveness of DHP for the inactivation of these pathogens was compared to that of hydrostatic high pressure (HHP) using the same pressure (200 MPa, single pass at 25 degrees C). In general, two additional log reductions in viable count were obtained with DHP DHP was less effective against L. monocytogenes and E. coli O157:H7 in raw milk than in PBS. After five passes at 200 MPa, an 8.3-log reduction was obtained for E. coli O157:H7, while a reduction of about 5.8 log CFU/ml was obtained for L. monocytogenes exposed to 300 MPa for five passes. Exposing milk or buffer samples to mild heating (45 to 60 degrees C) prior to dynamic pressurization enhanced the lethal effect of DHP The inactivation of pathogens also depended on the initial bacterial concentration. The highest reduction was obtained when the bacterial load did not exceed 10(5) CFU/ml. In conclusion, DHP was shown to be very effective for the destruction of the tested pathogens. It offers a promising alternative for the cold pasteurization of milk and possibly other liquid foods.     

Cations reduce antimicrobial efficacy of lysozyme-chelator combinations

Reduction of the antimicrobial efficacy of lysozyme-chelator combinations against two Escherichia coli O157:H7 strains on addition of mineral salts was studied. The objective of the study was to determine the effect of type and concentration of mono-, di-, and trivalent mineral salts on the antimicrobial effectiveness of lysozyme and various chelators against E. coli O157:H7. Seven salts (Al3+, Ca2+, Fe2+, Fe3+, K+, Mg2+, and Na+) at 1 to 10 mM were added to aqueous solutions of lysozyme and disodium ethylenediamine tetraacetic acid (EDTA), disodium pyrophosphate (DSPP), or pentasodium tripolyphosphate (PSTPP) at pH 6, 7, or 8 and applied to cultures of E. coli O157:H7 strains 932 and H1730. Inhibitory activity of lysozyme chelator combinations against both strains was completely lost after addition of > or = 1 mM Ca2+ and Mg2+ at pH 7 and 8. At pH 6, antimicrobial activity of lysozyme-EDTA against both strains was retained in the presence of calcium or magnesium cations. DSPP-lysozyme inhibited strain H1730 at pH 6 despite the presence of Mg2+. Concentrations above 4 mM Fe2+ neutralized activity of all lysozyme-chelator combinations. Reversal of inhibition by lysozyme-chelator complexes by the monovalent Na+ and K+ ions depended on E. coli O157:H7 strain type. Neither monovalent cation reversed inhibition of strain 932. However, Na+ and K+ reversed lysozyme-chelator inhibition of strain H1730. The addition of > or = 1 mM Fe3+ or Al3+ was effective in reversing inhibition of both strains by lysozyme and EDTA at pH 6, 7, and 8. Isothermal titration calorimetry was used to determine the amount of ion-specific competitive binding of free cations by EDTA-lysozyme combinations. A mechanistic model for the antimicrobial functionality of chelator-lysozyme combinations is proposed.     

Inactivation of Escherichia coli O157:H7 in orange juice using a combination of high pressure and mild heat

The effect of high pressure on the survival of a pressure-resistant strain of Escherichia coli O157:H7 (NCTC 12079) in orange juice was investigated over the pH range 3.4 to 5.0. The pH of commercial, sterile orange juice was adjusted to 3.4, 3.6, 3.9, 4.5, or 5.0. The juice was then inoculated with 10(8) CFU ml(-1) of E. coli O157:H7. The inoculated orange juice was subjected to pressure treatments of 400, 500, or 550 MPa at 20 degrees C or 30 degrees C to determine the conditions that would give a 6-log10 inactivation of E. coli O157:H7. A pressure treatment of 550 MPa for 5 min at 20 degrees C produced this level of kill at pH 3.4, 3.6, 3.9, and 4.5 but not at pH 5.0. Combining pressure treatment with mild heat (30 degrees C) did result in a 6-log10 inactivation at pH 5.0. Thus, the processing conditions (temperature and time) must be considered when pressure-treating orange juice to ensure microbiological safety.     

Quantitative determination of the role of lettuce leaf structures in protecting Escherichia coli O157:H7 from chlorine disinfection

Viability of Escherichia coli O157:H7 cells on lettuce leaves after 200 mg/liter (200 ppm) chlorine treatment and the role of lettuce leaf structures in protecting cells from chlorine inactivation were evaluated by confocal scanning microscopy (CSLM). Lettuce samples (2 by 2 cm) were inoculated by immersing in a suspension containing 10(9) CFU/ml of E. coli O157: H7 for 24+/-1 h at 4 degrees C. Rinsed samples were treated with 200 mg/liter (200 ppm) chlorine for 5 min at 22 degrees C. Viability of E. coli O157:H7 cells was evaluated by CSLM observation of samples stained with Sytox green (dead cell stain) and Alexa 594 conjugated antibody against E. coli O157:H7. Quantitative microscopic observations of viability were made at intact leaf surface, stomata, and damaged tissue. Most E. coli O157:H7 cells (68.3+/-16.2%) that had penetrated 30 to 40 microm from the damaged tissue surface remained viable after chlorine treatment. Cells on the surface survived least (25.2+/-15.8% survival), while cells that penetrated 0 to 10 microm from the damaged tissue surface or entered stomata showed intermediate survival (50.8 +/-13.5 and 45.6+/-9.7% survival, respectively). Viability was associated with the depth at which E. coli O157:H7 cells were in the stomata. Although cells on the leaf surface were mostly inactivated, some viable cells were observed in cracks of cuticle and on the trichome. These results demonstrate the importance of lettuce leaf structures in the protection of E. coli O157:H7 cells from chlorine inactivation.     

Use of linear, Weibull, and log-logistic functions to model pressure inactivation of seven foodborne pathogens in milk

Survival curves of six foodborne pathogens suspended in ultra high-temperature (UHT) whole milk and exposed to high hydrostatic pressure at 21.5 degrees C were obtained. Vibrio parahaemolyticus was treated at 300 MPa and other pathogens, Listeria monocytogenes, Escherichia coli O157:H7, Salmonella enterica serovar Enteritidis, Salmonella enterica serovar Typhimurium, and Staphylococcus aureus were treated at 600 MPa. All the survival curves showed a rapid initial drop in bacterial counts followed by tailing caused by a diminishing inactivation rate. A linear model and two nonlinear models were fitted to these data and the performances of these models were compared using mean square error (MSE) values. The log-logistic and Weibull models consistently produced better fits to the inactivation data than the linear model. The mean MSE value of the linear model was 6.1, while the mean MSE values were 0.7 for the Weibull model and 0.3 for the log-logistic model. There was no correlation between pressure resistance and the taxonomic group the bacteria belong to. The order, most to least pressure-sensitive, of the single strains tested was: V. parahaemolyticus (gram negative)相似文献   

银耳多糖对冻干植物乳杆菌细胞膜及糖代谢酶的保护作用

为了探索银耳多糖作为益生菌冻干保护剂的潜在应用,该研究以植物乳杆菌为试验菌,通过测定植物乳杆菌冻干前后的活菌数、细胞膜性质以及糖代谢酶活力的变化,评价了银耳多糖复合酪蛋白酸钠对植物乳杆菌的冻干保护效果。结果表明：当银耳多糖与酪蛋白酸钠的复合比例为3:1时,菌的最大存活率达到55.39%,此时细胞内钙离子荧光强度显著降低,为29.98;DPH的荧光强度最低,为4.91;细胞内乳酸脱氢酶、钠钾ATP酶与钙镁ATP酶的活力最大,分别为0.32 U/mL、121.61 U/g与45.64 U/g。银耳多糖使膜受损的菌百分比从98.35%最大降低至37.90%。但冻干前后己糖激酶和丙酮酸激酶的活力无显著性变化。红外扫描结果表明银耳多糖与酪蛋白酸钠之间存在非共价相互作用;此外,银耳多糖的保护使菌粉表面的孔隙率降低,酪蛋白酸钠的复合则增加了菌粉的致密性。因此,银耳多糖在冷冻干燥过程中对植物乳杆菌细胞膜受到的损伤具有显著的抑制作用,对植物乳杆菌的乳酸脱氢酶、钠钾ATP酶及钙镁ATP酶具有明显的保护作用。