壳聚糖及其金属锌配位络合物的抑菌性能研究

本研究在合成一种壳聚糖锌配合物后,测试了合成的壳聚糖锌、合成原材料壳聚糖的抑菌效果,以及不同pH条件对抑菌效果的影响,并比较了壳聚糖锌和常见的食品防腐剂苯甲酸钠、山梨酸钾对大肠杆菌ATCC8099、金黄色葡萄球菌ATCC6538、枯草杆菌黑色变种ATCC9372、白色念珠菌ATCC10231和黑曲霉ATCC16404的最低抑菌浓度。结果表明:合成的壳聚糖锌与合成前的壳聚糖相比抑菌性能大大提高;合成后的壳聚糖锌对细菌的抑菌效果与常见的食品防腐剂苯甲酸钠、山梨酸钾相当,但对真菌的抑制时效没有苯甲酸钠、山梨酸钾好。同时系统的pH对壳聚糖锌和壳聚糖都有较大的影响,酸性条件下抑菌效果较好。     

溶菌酶与壳聚糖复配液抑菌作用的研究

本实验以溶菌酶和壳聚糖联合使用以增强对三种模型菌(大肠杆菌(E.coli)、金黄色葡萄球菌(St.aureus)及白色念珠菌(C.albicans))的抑菌效果。首先采用抑菌圈法考察不同浓度醋酸溶液对不同浓度壳聚糖溶液抑菌效果的影响,其次通过对倍稀释法测定壳聚糖溶液和溶菌酶溶液的最小抑菌浓度(MIC),并采用定量法确定复配液的配比,最后通过酶标法监测加入复配抑菌剂后三种模型菌的生长曲线。结果表明,1%的醋酸溶液与壳聚糖的协同抑菌效果最好;壳聚糖溶液对三种模型菌的最小抑菌浓度均为0.1562mg/m L,溶菌酶溶液对大肠杆菌、金黄色葡萄球菌和白色念珠菌的最小抑菌浓度分别为0.625mg/mL、1.25mg/mL和1.25mg/mL,而复合液对三种模型菌的抑制作用优于单独使用溶菌酶或壳聚糖;复配液对大肠杆菌和金黄色葡萄球菌的抑制作用主要表现在对数生长期,而加入材料后白色念珠菌由延迟期直接进入稳定期内。     

水溶性壳聚糖对几种常见菌的抑制作用及其机理初探

采用固体培养基体外抑菌法,研究了水溶性壳聚糖对大肠杆菌、金黄色葡萄球菌、变形杆菌、白色念珠菌、绿脓杆菌的抑菌作用。结果表明,水溶性壳聚糖在1%HAc中的抑菌性强于在水中的抑菌性,在5种被试菌中,其对金黄色葡萄球菌和大肠杆菌的抑制作用最强。并初步探讨了水溶性壳聚糖的抑菌机理。     

壳聚糖、溶菌酶和牛至油对大豆分离蛋白膜抑菌效果的影响

采用双倍稀释法研究壳聚糖、溶菌酶和牛至油对大肠杆菌和金黄色葡萄球菌的最小抑菌浓度。采用抑菌圈法研究添加天然抑菌剂壳聚糖、溶菌酶和牛至油的大豆分离蛋白膜对大肠杆菌、金黄色葡萄球菌、酿酒酵母和黑曲霉的抑菌效果。结果表明,添加壳聚糖、溶菌酶和牛至油的大豆分离蛋白膜对大肠杆菌、金黄色葡萄球菌、酿酒酵母和黑曲霉均有抑制作用。对大肠杆菌和金黄色葡萄球菌抑制效果为:牛至油>壳聚糖>溶菌酶。对酿酒酵母的抑制效果为:壳聚糖>牛至油>溶菌酶;对黑曲霉的抑制效果为:牛至油>壳聚糖>溶菌酶。因此,添加壳聚糖、溶菌酶和牛至油的大豆分离蛋白膜具有较好的抑菌效果和应用前景。     

碘化壳聚糖溶胶在鞋材抗菌整理工艺中的应用

壳聚糖具有优良的抗细菌活性,在织物抗菌功能整理中已受到广泛关注,但其抗真菌的能力较差,难以在真菌感染严重的鞋材中广泛使用。利用冰醋酸和KI溶液对壳聚糖进行碘化,制备的碘化壳聚糖具有明显的抑制真菌的能力,同时也保留了其抑制细菌生长的能力,是一种具有双重抑菌特性的抗菌剂。碘化壳聚糖对大肠杆菌和金黄色葡萄球菌的最小抑菌浓度分别是2.6%和2.5%,对白色念珠菌和红色毛癣菌的最小抑菌浓度分别是1.1%和1.0%。碘化壳聚糖溶胶处理过的织物对大肠杆菌、金黄色葡萄球菌、白色念珠菌和红色毛癣菌的抑菌率分别为82.52%、81.65%、95.91%和99.07%。碘化壳聚糖的抗真菌能力明显优于壳聚糖,而其抗细菌能力较壳聚糖稍差一点。     

小分子羧甲基壳聚糖的抑菌性能研究

采用体外抑菌法分别测定不同小分子量羧甲基壳聚糖对几类菌种的抑制作用。结果表明3 000 u分子量的羧甲基壳聚糖对大肠杆菌、金黄色葡萄球菌、黑曲霉和酵母菌的最低抑菌浓度分别为:0.10%、0.15%、0.15%、0.15%;6 000 u分子量的羧甲基壳聚糖对大肠杆菌、金黄色葡萄球菌、黑曲霉和酵母菌的最低抑菌浓度分别为:0.15%、0.15%、0.20%、0.15%;9 000 u分子量的羧甲基壳聚糖对大肠杆菌、金黄色葡萄球菌、黑曲霉和酵母菌的最低抑菌浓度分别为:0.20%、0.10%、0.20%、0.20%。较高分子量的羧甲基壳聚糖对金黄色葡萄球菌的抑菌效果较好,低分子量的羧甲基壳聚糖对大肠杆菌、黑曲霉、酵母菌的抑菌效果较好。     

丹参提取液体外抑菌活性研究

目的 研究丹参提取液的体外抑菌作用.方法 采用常量肉汤稀释法测定最低抑菌浓度(MIC),探讨其体外抑菌作用.采用杯碟法检测丹参不同提取方式、不同灭菌方式以及改变提取液pH值对金黄色葡萄球菌抑菌活性的影响.结果 丹参醇提液对大肠埃希菌、金黄色葡萄球菌、枯草芽胞杆菌、铜绿假单胞杆菌、短小芽胞杆菌均有抑菌作用,其95%醇提液对上述菌的MIC分别为20,20,40,80,80 mg/mL,对白色念珠菌无抑菌作用.丹参醇提液对大肠埃希菌、金黄色葡萄球菌抑菌活性较强;不同灭菌方式及改变提取液pH值对金黄色葡萄球菌抑菌活性无差异.结论 丹参提取液具有一定抑菌作用.     

鱿鱼骨壳聚糖的抑菌性能研究

研究了鱿鱼骨壳聚糖对食品中常见微生物的抑制作用,以大肠杆菌、金黄色葡萄球菌、啤酒酵母、黑曲霉等为受试菌,研究了2种不同相对分子量的鱿鱼骨壳聚糖(1210、844kD)的抑菌性能,并探讨了壳聚糖抑菌作用的稳定性.结果表明,两种壳聚糖对四种菌都有明显的抑制作用,相应最小抑菌浓度对大肠杆菌为0.02%,对金黄色葡萄球菌、啤酒酵母、黑曲霉均为0.05%,壳聚糖的抑菌作用具有良好的热稳定性.     

酪蛋白酶解物中抗菌肽的抑菌性及稳定性研究

对酪蛋白胰蛋白酶酶解物中抗菌肽的抗菌性及稳定性进行研究。实验通过以大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌和蜡样芽胞杆菌为指示菌,验证了抗菌肽的抑菌性,并以大肠杆菌为指示菌,研究了酶解物中抗菌肽在不同温度、不同pH值、不同储藏时间条件下的抑菌稳定性。结果表明:此抗菌肽能有效抑制大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌和蜡样芽胞杆菌的生长,具有广谱抗菌活性;碱性及中性条件下,此抗菌肽对大肠杆菌抑菌活性稳定,酸性条件下,抑菌活性随pH值下降而增强;此抗菌肽冻干样品在室温下可长期储藏。     

仙草提取物体外抑菌的研究

本文利用醇提法获得的仙草提取物分别对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌、铜绿假单胞、乳酸菌、酵母和黑曲霉做了体外抑菌实验,并对起抑菌作用的可能物质黄酮类化合物做了测定。结果表明,仙草全草提取物对大肠杆菌CMCC44102、金黄色葡萄球菌ATCC25923、枯草芽孢杆菌CMCC(B)63501、铜绿假单胞ATCC27853、嗜热链球菌ATCC14485和保加利亚杆菌CICC6045的最小抑菌浓度分别为3、0.6、6、0.6、3和3g/mL(生药质量浓度);对黑曲霉和酵母无明显抑制作用。仙草全草提取物芦丁含量为50.15mg/g,与抑菌效果有一定的关联性。     

植物精油对微生物的抑菌效果评估研究

本实验以大肠杆菌(Escherichia coli)8099、金黄色葡萄球菌(Staphylococcus aureus)ATCC6538、枯草杆菌黑色变种(Bacillus subtilis)ATCC9372、白色念珠菌(Candida albicans)ATCC10231和黑曲霉(Aspergillus niger ATCC16404)为指示菌,采用纸片法和试管法评估了42种植物精油的抑菌效果,结果显示植物精油对真菌和革兰氏阳性细菌的抑杀效果好,其中有11种精油对5种指示菌的抑杀效果较好,由强至弱的顺序为:肉桂、百里香、柠檬草、香茅、香茅油、雪松、山鸡椒、天竺葵、桂皮油、芫荽、罗勒、山苍子油、欧薄荷、茴香。     

Direct contact membrane inoculation of yeasts and moulds for evaluating preservative efficacy in solid cosmetics

A direct contact membrane inoculation technique for yeasts and moulds was used to evaluate the preservation efficacy and antimicrobial activity of Germall 115 and Germall II in pressed eye shadows. Test organisms on membrane filters were placed in direct contact with cosmetics at room temperature under humid conditions. Growth on membranes was removed daily, or as appropriate, and cultured on potato dextrose agar containing lecithin and Tween 80. Linear regression analysis was used to determine product preservation efficacy. Average D values of 1 and 3 days for Candida albicans American Type Culture Collection (ATCC) 10231 and 17 and 29 days for Aspergillus niger ATCC 16404 were obtained on two eye shadows we prepared (in-house eye shadows) with parabens and either Germall II or Germall 115 as preservatives. A decimal reduction time (D value) of 6–7 days was calculated for the yeast on a commercial eye shadow preserved with parabens and Germall 115. A. niger multiplied on six of seven replicates of this commercial product to attain a nearly 3 log₁₀ increase in 20 days. On one replicate, A. niger showed a 1 log₁₀ increase in the first 10 days, and then decreased linearly (r =— 0.95) to <10 colony-forming units per membrane by day 24. The method used with C. albicans and A. niger was then used with bacteria. The method was sensitive enough to differentiate the antimicrobial activity of the Germall 115 and Germall II against fungi but not against bacteria. The in-house and commercial products were preserved most effectively against the three bacteria tested and least effectively against the mould.     

Bacterial spore injury during extrusion cooking of corn/soybean mixtures

This study examined the potential for injury of Bacillus globigii (Bacillus subtilis var. niger, strain ATCC9372) spores during extrusion cooking of a corn/soybean (70/30%, w/v) mixture. The barrel temperature in zone 1 was kept constant at 80 degrees C while it was varied from 100 to 120 and 140 degrees C in zone 2. Recovery and enumeration of spores surviving the extrusion cooking process were conducted with five culture media ranging from minimal to rich in nutrient composition. Numbers of spores counted with a minimal culture medium after extrusion at the low temperature were lower compared to recovery with more complete media. All culture media, including minimal and richer, were equally effective in recovering untreated spores. At the higher extrusion temperatures all media were equally effective in recovering the small numbers of viable spores. The results indicated that the spores of the organism may be injured at lower extrusion temperatures.     

Adequacy of cosmetic preservation: chemical analysis, microbial challenge and in-use testing

The adequacy of preservation of seven previously unopened commercial cosmetic products was tested by individual challenges with Aspergillus niger ATCC 9642, Candida albicans ATCC 10231, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 15422, and Staphylococcus aureus ATCC 6538, using the Cosmetic, Toiletry, and Fragrance Association (CTFA) method. Each product was consecutively challenged three times, 28 days apart. Inoculated composite products were counted by conventional techniques at eight prefixed intervals. Six of seven cosmetics passed the CTFA acceptance criteria. On the basis of viable counts seven days after inoculation (CTFA criteria), the products were classified as follows: five products were well preserved, one was marginally preserved, and one was poorly preserved. The poorly preserved product failed the CTFA criteria for all three bacteria tested. Concentrations of preservative ingredients in uninoculated composites were determined by high performance liquid chromatography. All preservatives listed on the labels of the seven cosmetic products were identified by chemical analysis. Tentative in-use validation of the CTFA criteria was performed for three of the seven cosmetic formulations. The results suggested that some cosmetic products may be underpreserved.     

气相法白炭黑季铵盐衍生物的皮革防霉和抗细菌作用

以气相法白炭黑(FS)、偶联剂和叔胺为原料,合成了3种气相法白炭黑季铵盐衍生物(DQAFS),并用红外光谱对其结构进行了表征。防霉抗菌试验表明:用悬菌定量法,3种DQAFS对大肠杆菌(8099)和金黄色葡萄球菌(ATCC6538)的15min抑菌率都达到99.99%,而对采自蓝湿革的混合霉菌的抑制效果则有很大区别,定性试验结果表明,有的是完全抑制,有的几乎无作用。     

Supercritical carbon dioxide extraction of compounds with antimicrobial activity from Origanum vulgare L.: determination of optimal extraction parameters

Oregano leaves were extracted using a pilot-scale supercritical fluid extraction plant under a wide range of extraction conditions, with the goal of determining the extraction and fractionation conditions to obtain extracts with optimal antimicrobial activity. In this investigation, the essential oil-rich fractions were selectively precipitated in the second separator, and their chemical composition and antimicrobial activity were investigated. Gas chromatography-mass spectrometry analysis of the various fractions resulted in the identification of 27 compounds of the essential oil. The main components of these fractions were carvacrol, trans-sabinene hydrate, cis-piperitol, borneol, terpinen-4-ol, and linalool. Antimicrobial activity was investigated by the disk diffusion and broth dilution methods against six different microbial species, including two gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), two gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), a yeast (Candida albicans), and a fungus (Aspergillus niger). All of the supercritical fluid extraction fractions obtained showed antimicrobial activity against all of the microorganisms tested, although the most active fraction was the one obtained in experiment 5 (fraction was obtained with 7% ethanol at 150 bar and 40 degrees C). C. albicans was the most sensitive microorganism to the oregano extracts, whereas the least susceptible was A. niger. Carvacrol, sabinene hydrate, borneol, and linalool standards also showed antimicrobial activity against all of the microorganisms tested, with carvacrol being the most effective. Consequently, it was confirmed that essential oil from experiment 5, with the best antimicrobial activity, also presented the highest quantity of carvacrol.     

Development of a sanitizing fabric wipe for use on food contact surfaces

ABSTRACT:  A sanitizer was incorporated into disposable sanitary wipes that were used to eliminate microorganisms on plastic and metal surfaces. These surfaces were inoculated with strains of Bacillus subtilis OSU 494, Enterococcus faecalis OSU 48, Escherichia coli ATCC 29181, Listeria innocua ATCC 33090, Pseudomonas aeruginosa OSU 167, Salmonella enteritidis OSU 799, Staphylococcus epidermidis OSU 838), Candida albicans ATCC 10231, and Aspergillus fumigatus ATCC 10894. These inoculated surfaces were cleaned with the wipes for 5, 10, and 30 s, then organisms surviving on the cleaned surfaces and in the wipes were enumerated. Applying the sanitizing wipe to the plastic and metal surfaces reduced the viability of bacteria (> log 4 for 5 s), yeast cells (> log 5 for 10 s), and fungal spores (< log 4 for all times). The use of large pore sized or thick wipes showed better sanitizing result when compared with the use of the small pore sized and slim wipe. There were no significant differences ( P > 0.05) between surviving numbers on the surface of the plastic compared with that of the metal.     

多粘菌素B抑制丝状真菌的定量测定方法研究

为规范抗菌肽抑制丝状真菌的活力评价方法,采用多粘菌素B为抗菌肽研究对象,以黑曲霉(Aspergillus niger ATCC 16404)和产黄青霉(Pencillinm chrysogenum ATCC 10106)为指示菌,选用察氏培养基(20 mL培养基/90 mm平板)比较孢子萌发抑制法和菌丝生长抑制法,获得适合丝状真菌的测定方法,并进一步研究该方法的最适测定条件。结果表明,菌丝生长抑制法更适用于多粘菌素B抑制2株丝状真菌的定量检测。其中多粘菌素B抑制Aspergillus niger ATCC 16404的最适条件:指示菌培养48 h,接种菌饼直径(8.00±0.02) mm,在此条件下,测得多粘菌素B的EC₅₀为0.68 mg/mL;多粘菌素B抑制Pencillinm chrysogenum ATCC 10106的适宜条件:指示菌培养72 h,接种菌饼直径(5.80±0.02) mm,此时多粘菌素B的EC₅₀为0.45 mg/mL。本研究建立的抗菌肽抑制丝状真菌的活力测定方法具有普遍适用性,可为抗菌肽活性测定方法的规范及评价标准的建立奠定基础。     

槐花精油的化学成分及其抑菌活性的研究

采用同时蒸馏萃取法提取槐花精油,用气相-质普联用技术(GC-MS)分析其化学成分;鉴定出43种化合物,占出峰总面积的98.49 %;主要成分为十六酸(38.69%)、亚油酸甲酯(10.13%)、2-甲氧基-4-(2-丙烯基)-苯酚(6.71%)、亚麻酸(6.35%)、2-羟基-3-甲基-4H-吡喃-4-酮(3.49%)、8-十七碳烯(2.44%)、二苯砜(2.44%)、6,10,14-三甲基-2-十五酮(1.85%)、4-乙烯基-2-甲氧基苯酚(1.82%)等.体外抑菌实验显示该精油对金黄色葡萄球菌ATCC 6538、伤寒沙门氏菌CMCC50013、志贺氏痢疾杆菌CMCC51334、埃希氏大肠杆菌ATCC 8099均有抑制作用.