Antibacterial effect of water-soluble arrowroot (Puerariae radix) tea extracts on foodborne pathogens in ground beef and mushroom soup

Antimicrobial activity of water-soluble arrowroot tea extract was evaluated against Escherichia coli O157:H7, Salmonella enterica Serotype Enteritidis, Listeria monocytogenes, and Staphylococcus aureus in ground beef and mushroom soup. The concentrations of arrowroot tea used were 0, 3, and 6% (wt/wt) for ground beef and 0, 1, 5, and 10% (wt/vol) for mushroom soup. Samples without tea extract were considered controls. Each sample was stored for 0, 1, 3, 5, and 7 days at 7 degrees C for ground beef and for 0, 1, 3, and 5 days at 35 degrees C for mushroom soup. On each sampling time, proper dilutions were spread plated on each pathogen-specific agar. Viable cell counts of each pathogen were performed after incubation at 35 degrees C for 24 to 48 h. For ground beef, Salmonella Enteritidis and L. monocytogenes were slightly suppressed by approximately 1.5 log, compared with the control, on day 7 at 3 and 6% arrowroot tea treatment. For mushroom soup, all test pathogens were suppressed by 6.5, 4.7, 3.4, and 4.3 log at 5% and 6.0, 4.7, 5.0, and 4.3 log at 10% against E. coli O157:H7, Salmonella Enteritidis, L. monocytogenes, and S. aureus, respectively, compared with the control on day 5. Mushroom soup with 1% arrowroot tea also showed 2.3- and 2.7-log growth suppression of Salmonella Enteritidis and S. aureus, respectively, compared with the control on day 5. This study showed that the use of arrowroot tea would effectively inhibit the microbial growth of both gram-negative and gram-positive foodborne pathogens in various foods, especially liquid foods.     

柠檬酸钠与桂皮提取物对各种革兰氏阴性食源性病原菌的抑菌效果

以乙醇为提取物,提取桂皮中的有效成分。首先测定了其对各种食源性病原菌的杀菌效果,接着观察了该提取物和柠檬酸钠协同作用下,对几种革兰氏阴性食源性病原菌的杀菌效果。结果表明,对于金黄色葡萄球菌等革兰氏阳性食源性病原菌,桂皮提取物显示了明显的抑菌效果与杀菌效果。而对大肠杆菌、沙门氏菌等革兰氏阴性食源性病原菌,则显示了较弱的抗菌效果。桂皮提取物与柠檬酸钠的并用对各种革兰氏阴性食源性病原菌均显示了明显的协同效应;对于肠出血性大肠杆菌、肠炎沙门氏菌、鼠伤寒沙门氏菌,柠檬酸钠明显的提高了桂皮提取物的杀菌活性,显示了良好的协同效果。     

辐照技术对食源性病原菌的影响研究

食源性病原菌,指在食品加工和流通过程中引入的病原菌,是引发食源性疾病的重要因素。这些病原菌以食品作为载体进行传播,一定程度上增加了某些食源性疾病爆发的可能,而传统的控制措施抑菌效果有限,当务之急是寻求革新的食品杀菌技术。食品辐照技术作为一种高新的冷杀菌技术,具有安全、无污染等优点,近年来在保障食品质量安全方面发挥的作用也引起了社会的高度重视,关于辐照技术对食品中病原菌致死作用的系统描述相对较少。本文结合国内外关于食品辐照灭菌的研究报道,综述了辐照技术的发展、辐照技术控制食品病原菌进展、辐照杀菌机制以及影响辐照灭菌效果的主要因素,并对该技术存在的问题和未来的研究进行了探讨,以期为进一步预防和控制食源性疾病提供新的思路。     

Survival of foodborne pathogens on stainless steel soiled with different food residues

Food Science and Biotechnology - Insufficient and ineffective cleaning practices can cause food residues to remain in kitchen and can facilitate bacterial attachment and persistence by protective...     

Antibacterial activities of polyphenols against foodborne pathogens and their application as antibacterial agents

Food Science and Biotechnology - Polyphenols are secondary metabolites produced in higher plants. They are known to possess various functional properties in the human body. Polyphenols also exhibit...     

2016年松原市食品中食源性致病菌的风险监测

［］目的 了解松原市市售食品的食源性致病菌污染状况。方法 2016年采集全市五个县、市(区)12类食品,依据吉林省2016年食源性致病菌监测工作手册,检测沙门氏菌、金黄色葡萄球菌、副溶血性弧菌、单增李斯特氏菌、阪崎肠杆菌、蜡样芽孢杆菌、致泻性大肠杆菌等7种致病菌。结果 在采集的12类共205份食品中,检出致病菌22株,总检出率为10.7%。在8种致病菌中,阪崎肠杆菌检出率最高30%,其次是蜡样芽孢杆菌11.1%。在12类食品中,婴幼儿谷类辅助食品污染率最高45%,其次为学生餐26.7%。动物性淡水产品、即食非发酵豆制品、鲜榨果蔬汁等食品均存在不同程度的污染。结论 松原市食品中存在不同程度的食源性致病菌污染,婴幼儿食品存在受致病菌污染的风险,其食品安全应得到重视和加强监管。     

Antibacterial activity in extracts of Camellia japonica L. petals and its application to a model food system

The potential presence of naturally occurring antimicrobials in petals of Camellia japonica L., a member of the tea family, was investigated against foodborne pathogens in microbiological media and food. Petals of the camellia flower (C. japonica L.) were extracted with methanol and fractionated into basic, acidic, and neutral fractions. The acidic fraction (equivalent to 1.0 g of raw sample per disk) produced an inhibitory zone of 14 to 19 mm (diameter) in a disk assay against the pathogens Salmonella Typhimurium DT104, Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus on agar plates. Silica gel adsorption column chromatography, Sephadex LH-20 column chromatography, and preparative purification by high-pressure liquid chromatography were used to purify compounds in the fraction. The mass spectrum of the antibacterial compound isolated had a molecular ion (M+) of m/z 116 and showed good conformity with the spectrum of fumaric acid (HOOC-CH=CH-COOH). An aqueous extract from the petals of C. japonica L. had an inhibitory effect on growth of all pathogens at 37 degrees C in microbiological media by increasing the lag phase. None of the microorganisms was inhibited completely. Milk was used as a model food system. Aqueous extract at a concentration of 100 mg/ml was bacteriostatic against all the foodborne pathogens in the milk stored at 25 degrees C for up to 4 days.     

Antibacterial effects of American cranberry (Vaccinium macrocarpon) concentrate on foodborne pathogens

Antibacterial effects of American cranberry (Vaccinium macrocarpon) concentrate on foodborne pathogens, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium, and Staphylococcus aureus in vitro were investigated. Cranberry concentrate at various concentrations was prepared in distilled water (DW) or Brain Heart Infusion (BHI) broth. Pathogens were inoculated in each sample and incubated at 21 and 4 °C for 0, 1, 5, 7, and 24 h (DW samples) and 0, 1, 3, and 5 days (BHI samples). Transmission electron microscopy (TEM) was used to study the effects of cranberry concentrate on cellular structure of pathogens. DW results showed that S. Typhimurium and L. monocytogenes were reduced to non-detectable levels at 5 h in 100 μl/ml treatment at 21 and 4 °C. At 24 h, no target pathogens were detected from the 100 μl/ml treatment. BHI data indicated that the 100 μl/ml treatment reduced the four pathogens by 3-8 log CFU/ml compared with the control on Day 5 at 21 and 4 °C. TEM revealed damage to the bacterial cell walls and membranes. Cranberry concentrate has antibacterial effects on the four foodborne pathogens. Based on potential health benefits and proven antimicrobial effects, American cranberry concentrate may have dual applications as a food preservative.     

鲜榨柠檬原汁对7种常见食源性致病菌抑菌效果及被膜形成的影响

目的研究鲜榨柠檬果皮和果肉原汁对7种常见食源性致病菌的抑菌效果以及对生物被膜形成的影响。方法对柠檬果皮和果肉分别榨汁测定总酸;采用顶空取样结合气相色谱-质谱联用技术(GC-MS)分析鲜榨柠檬果皮和果肉原汁中的主要挥发性成分;采用平板抑菌试验研究两种鲜榨原汁的抑菌效果;采用试管法和96孔板法研究两种鲜榨原汁对细菌生物被膜形成的影响。结果鲜榨柠檬果肉原汁总酸为98.86 g/kg,鲜榨柠檬果皮原汁总酸为6.05 g/kg;GC-MS结果表明鲜榨柠檬果皮和果肉原汁中主要挥发性成分以柠檬烯、γ-萜品烯、α-松油醇、柠檬醛等为主;鲜榨柠檬果肉原汁对7种常见食源性致病菌均具有明显抑菌效果,鲜榨柠檬果皮原汁均未出现明显抑菌作用;鲜榨柠檬果肉原汁对部分细菌被膜形成有抑制作用,鲜榨柠檬果皮原汁对部分细菌被膜形成有明显促进作用。结论鲜榨柠檬原汁对常见食源性致病菌生长及被膜形成影响的研究为食源性致病菌的防控提供了科学依据。     

Antibacterial activity of xanthorrhizol isolated from Curcuma xanthorrhiza Roxb. against foodborne pathogens

Xanthorrhizol, isolated from the ethanol extract of Curcuma xanthorrhiza Roxb., is a sesquiterpene compound with a molecular weight of 218. The aim of this study was to investigate the antibacterial activity of xanthorrhizol against foodborne pathogens. The antibacterial activity of xanthorrhizol was measured in terms of the MIC and the MBC. MICs and MBCs of xanthorrhizol against Bacillus cereus, Clostridium perfringens, Listeria monocytogenes, Staphylococcus aureus, Salmonella Typhimurium, and Vibrio parahaemolyticus were 8, 16, 8, 8, 16, 8 microg/ml and 16, 32, 16, 16, 16, 16 microg/ml, respectively. The bactericidal study, as determined by the viable cell count method, revealed that xanthorrhizol treatment at 4 x MIC reduced viable cells by at least 6 to 8 log for all six foodborne pathogens in 4 h. Xanthorrhizol maintained its antibacterial activity after thermal treatments (121 degrees C, 15 min) under various pH ranges (pH 3.0, 7.0, and 11.0). These results strongly suggest that xanthorrhizol, conferring strong antibacterial activity with thermal and pH stability, can be effectively used as a natural preservative to prevent the growth of foodborne pathogens.     

2010~2012年咸阳市食源性致病菌监测结果分析

目的 了解咸阳市各类食品中食源性致病菌的污染情况, 确定可能污染上述致病菌的食品种类。方法 依照国标方法, 对食品分别进行增菌培养, 将菌体划线接种到相应的显色培养基培养, 挑选可疑菌落进行生化反应鉴定。结果 在803份不同的食品中共检出含致病菌74株, 总检出率9.02%。结论 本地主要消费食品存在一定的食源性致病菌污染, 金黄色葡萄球菌、单核细胞增生李斯特菌和沙门氏菌是主要引起食品污染的危险菌; 熟肉制品、中式凉拌菜和凉皮是最可能被致病菌污染的食品。     

延边地区2011~2015年食品中食源性致病菌的监测

【目的】 了解食品中主要食源性致病菌的污染状况,确定高危食品,为预防和控制食源性疾病提供科学依据。 【方法】 按照《全国食源性致病菌监测工作手册》 的检测技术要求,2011 － 2015 年在延边地区的几个监测点采集食品样品1069份,对沙门氏菌、单核细胞增生李斯特菌（定量）、金黄色葡萄球菌（定量）、铜绿假单胞菌、蜡样芽孢杆菌的污染情况进行监测。 【结果】 1069份样品中,共检出致病菌115株,总检出率为10.76%.熟肉制品、生食动物性水产品、凉拌菜、熟制米面制品、婴幼儿食品、乳及乳制品、速冻米面品、特殊膳食用食品、饮用水、三明治以及流动早餐样品的致病菌检出率分别为17.65%（3/17)、15.79%（3/19)、11.76%(4/34)、34.48%(10/29)、33.80%（24/71）、40.00%(12/30)、6.67%(1/15)、42.86%(6/14)、58.33%（7/12）、10.00%（1/10）和71.43%（10/14）;2011-2015年食源性致病菌检出率分别为0.94% 、1.87% 、6.83% 、0.65%、0.19%。 【结论】 乳及乳制品、特殊膳食用食品、饮用水和流动早餐是延边地区食品的主要污染品种,作为直接入口食品的熟肉制品、凉拌菜、熟制米面制品和婴幼儿食品可能导致较高的食源性疾病风险。     

韭菜醇浸提物GC/MS分析及对食品污染菌的抑制作用

为了解韭菜浸提物的成分与抑菌作用,采用乙醇对韭菜叶片进行浸提,并利用GC/MS进行成分分析和滤纸片法来测定韭菜粗提取物对食品污染菌的抑菌作用,结果表明,浸提物中主要有10种组分,硫醚类含量较高。浸提物抑菌作用的大小与其体积分数有关,100%韭菜浸提物对金黄色葡萄球菌、沙门氏菌、绿脓杆菌、大肠杆菌、奇异变形杆菌都具有抑制作用,其中对大肠杆菌的抑菌作用最强,不同菌株之间的抑菌效果有显著性差异。20%韭菜浸提物对不同菌株的抑菌效果无显著性差异。韭菜浸提物可以作为植物源抑菌物质和果蔬保鲜剂应用。     

五倍子单宁对常见食品腐败菌和致病菌抑制作用研究

研究了五倍子单宁对6种常见食品腐败菌和致病菌的抑菌作用。采用琼脂二倍稀释法和牛津杯法测定了五倍子单宁的最小抑菌浓度及抑菌活性;用扫描电镜观察了高敏杆菌大肠杆菌的形态变化。结果表明,五倍子单宁对各测试菌均有抑制作用,对大肠杆菌效果最好,最小抑菌浓度为0.25mg/mL,并且使菌体出现明显的凹陷。      

Microbiology and foodborne pathogens in honey

Honey has been considered a relatively safe foodstuff due to its compositional properties, with infant botulism caused by Clostridium botulinum being the most prominent health risk associated with it. Our review is focused on the honey microflora along the food chain and evaluates the pathogenic potential of those microorganisms found in honey. This product may contain a great variety of bacteria and, particularly, fungi that eventually entered the food chain at an early stage (e.g., via pollen). For many of these microorganisms, opportunistic infections in humans have been recorded (e.g., infections by Staphylococcus spp., Citrobacter spp., Escherichia coli, Hafnia alvei, Aspergillus spp., Fusarium spp., Trichoderma spp., Chaetomium spp.), although direct infections via honey were not registered.     

Antibacterial mode of action of seed essential oil of Eleutherococcus senticosus against foodborne pathogens

This study investigated the antibacterial mechanism of action of the seed essential oil of Eleutherococcus senticosus (ESEO) against foodborne pathogenic bacteria. Preliminarily, the ESEO (1000 μg disc^?1) showed potential antibacterial effect as diameter of inhibition zones (12.0 ± 0.2–37.0 ± 2.0 mm) against the tested foodborne pathogens. The MIC and MBC values of ESEO against the tested bacteria were found in the range of 125–500 and 500–1000 μg mL^?1, respectively. At MIC concentration, the ESEO had potential inhibitory effect on the cell viability of the tested pathogens. In addition, SEM analysis showed the inhibitory effect of ESEO as confirmed by considerable morphological alterations on the cell wall of B. cereus ATCC 13061 and E. coli O157:H7 ATCC 43889. Moreover, the ESEO revealed its mode of action against foodborne pathogens on membrane integrity as confirmed by release of extracellular ATP, 260‐nm absorbing materials and leakage of potassium ions. These findings confirm that the ESEO can be used as a potential antibacterial agent in food industry to inhibit the growth of various foodborne pathogens.     

Antibacterial activities of peptides from the water-soluble extracts of Italian cheese varieties

Water-soluble extracts of 9 Italian cheese varieties that differed mainly for type of cheese milk, starter, technology, and time of ripening were fractionated by reversed-phase fast protein liquid chromatography, and the antimicrobial activity of each fraction was first assayed toward Lactobacillus sakei A15 by well-diffusion assay. Active fractions were further analyzed by HPLC coupled to electrospray ionization-ion trap mass spectrometry, and peptide sequences were identified by comparison with a proteomic database. Parmigiano Reggiano, Fossa, and Gorgonzola water-soluble extracts did not show antibacterial peptides. Fractions of Pecorino Romano, Canestrato Pugliese, Crescenza, and Caprino del Piemonte contained a mixture of peptides with a high degree of homology. Pasta filata cheeses (Caciocavallo and Mozzarella) also had antibacterial peptides. Peptides showed high levels of homology with N-terminal, C-terminal, or whole fragments of well known antimicrobial or multifunctional peptides reported in the literature: α_S1-casokinin (e.g., sheep α_S1-casein (CN) f22-30 of Pecorino Romano and cow α_S1-CN f24-33 of Canestrato Pugliese); isracidin (e.g., sheep α_S1-CN f10-21 of Pecorino Romano); kappacin and casoplatelin (e.g., cow κ-CN f106-115 of Canestrato Pugliese and Crescenza); and β-casomorphin-11 (e.g., goat β-CN f60-68 of Caprino del Piemonte). As shown by the broth microdilution technique, most of the water-soluble fractions had a large spectrum of inhibition (minimal inhibitory concentration of 20 to 200 μg/mL) toward gram-positive and gram-negative bacterial species, including potentially pathogenic bacteria of clinical interest. Cheeses manufactured from different types of cheese milk (cow, sheep, and goat) have the potential to generate similar peptides with antimicrobial activity.     

2013~2014年长春市食品中食源性致病菌检测及分析

目的 了解食源性致病菌在长春市食品中检出情况,为食源性疾病防控工作提供科学的数据。方法 按《2103年国家食品污染和有害因素风险监测工作手册方法》、《 微生物检测方法的标准操作程序 》( 国家食品安全风险评估中心 )和国家标准方法进行食品中的食源性致病菌检测。结果 2013-2014年长春市11类食品433件样本中的食源性致菌的检出率是17.09%,其中蜡样芽胞杆菌、单核细胞增生李斯特氏菌、金黄色葡萄球菌和沙门氏菌的检出率分别是33.87%、12.81%、2.83%和0.58%。2013年和2014年食品中食源性致病菌的检出率无显著性差异(x₂=0.09,P＞0.05)。在乳制品、肉及其制品、婴幼儿食品、水产及其制品、餐饮食品、即食非发酵豆制品和速冻面米制品中食源性致病菌的检出率分别是：73.33%、40%、30.61%、9.52%、7.23%、5%和3.33%。结论 长春市食品存在不同程度上的食源性致病菌污染。乳制品、肉及其制品和婴幼儿食品中的食源性致病菌检出率较高,蜡样芽胞杆菌和单核细胞增生李斯特氏菌对食品污染较严重,需加强对这几类食品的监管。     

水葱提取物的抗菌作用研究

对水葱全草以乙醇、正己烷、丙酮、正丁醇作为溶剂提取有效成分,采用抑菌圈法测定了提取物对7种受试菌的抑菌作用,用稀释法测定了受试菌的MIC。结果表明:水葱提取物有较强的抑菌活性。其中乙醇提取液对黑曲霉、枯草杆菌的MIC为1.25mg/mL,正丁醇提取物对黑曲霉的MIC为2.5mg/mL,乙醇提取物抑菌活性总体好于其他溶剂提取物。实验测试了不同温度条件下提取物的抑菌活性以及提取物对食物的防腐作用,表明水葱提取液具有较好的热稳定性和防腐效果。     

2010~2015年吉林市食品食源性致病菌的风险监测结果分析

目的 分析吉林市市售食品中食源性致病菌的污染情况,确定高危食品的种类和分布,预防和控制食源性疾病的发生。方法 2010～2015年采集吉林市市售样品21类1212份,按照《全国食源性致病菌监测工作手册》的要求分离和鉴定10种食源性致病菌。结果 检出致病菌株121株,总检出率为9.98%。致病菌检出率前3位食品类别分别是速冻米面制品(26/96,27.08%);乳与乳制品、婴幼儿配斱食品(23/101,22.77%);肉及肉制品(40/178, 22.47%)。检出致病菌前3位是蜡样芽胞杆菌(43/206, 20.87%)、副溶血性弧菌(6/77, 7.79%)、单核细胞增生李斯特菌(42/643, 6.53%)。2010～2015年每年食源性致病菌检出率分别为8.56%、2.99%、6.55%、2.86%、1.83%、3.49%。结论 吉林市市售食品的现状不容乐观,食源性致病菌污染严重,致病菌检出率进高于同期本省及国内其他省市。建议长期注意其引起的食源性疾病风险,加强市售食品的监测和食品经营部门的管理,防止食源性疾病的发生。