基于益生菌及其代谢物的食源性致病微生物控制技术研究进展

食源性致病微生物不仅会引起食品腐败,造成经济损失,也给人类健康带来很大威胁,因此亟需开发高效、安全、不影响食品品质的食源性致病微生物控制技术。益生菌是近年微生物和食品科研领域研究热点,益生菌除具有调节和改善健康功能,其本身及代谢物对微生物较强的清除和抑制作用,使其可应用于对食源性致病微生物的控制。明悉益生菌及其代谢物类型、潜在的抑制微生物机制以及应用现状对相关控制技术的研发至关重要。分析了现有益生菌及其代谢物对食源性致病微生物的抑制机制,主要为破坏细胞结构、影响遗传物质复制、阻断能量代谢途径、干扰群体感应系统、控制生物被膜形成、竞争关键性营养物质等方面的单机制或多机制联合作用;同时基于目前益生菌及其代谢物在食品安全和品质控制中的应用研究实例,探讨了其在果蔬、肉类等食品中的应用方式、应用条件,对货架期的延长效果等;分析了益生菌及其代谢物在抗菌效能提高、活性包装、与其他食品品质控制技术联用等方面研究的发展趋势。研究结果旨在为基于益生菌及其代谢物的食品安全和品质控制技术的开发和应用提供借鉴和参考。     

食源性致病菌诱导细胞凋亡机理研究进展

细胞凋亡是机体为清理衰老、受损的细胞,维持内环境稳定、确保机体健康而采取的一种有序性“自杀方式”。食源性致病菌进入机体后可通过诱导宿主细胞凋亡以逃离宿主的免疫清除,保证自身生存进而得以在机体内扩散的生存策略。近年来研究表明,食源性致病菌的毒力因子在致病菌诱导宿主细胞凋亡过程中起到非常重要的作用,许多致病菌通过产生相应的毒力因子与凋亡调控因子相结合,引起细胞凋亡的级联反应。本文主要从致病菌毒力因子对凋亡信号通路的影响和调控方面来阐述食源性致病菌诱导细胞凋亡的机理研究进展。     

乳酸菌拮抗食源性致病菌的研究及应用进展

食品在生产加工、物流运输和贮存消费过程中均可能出现被食源性致病菌污染的风险,造成安全隐患,目前通过热加工、辐照、电解水和等离子体等方法来控制食品中食源性致病菌,但在食品感官、规模化应用和安全生产等方面存在部分缺点.乳酸菌因其丰富的生物活性常作为生物发酵剂和保鲜剂广泛应用于食品中,并且可在食品中拮抗致病菌.本文主要从竞争...     

Assessment of potential probiotic properties of Lactobacillus spp., Lactococcus spp., and Pediococcus spp. strains isolated from kefir

In this study, the metabolic activities (in terms of quantities of the produced lactic acid, hydrogen peroxide, and exopolysaccharides) of 8 strains of Lactobacillus spp., Lactococcus spp., and Pediococcus spp., were determined. Lactic acid levels produced by strains were 8.1 to 17.4 mg/L. The L. acidophilus Z1L strain produced the maximum amount (3.18 μg/mL) of hydrogen peroxide. The exopolysaccharides (EPS) production by the strains was ranged between 173 and 378 mg/L. The susceptibility of 7 different antibiotics against these strains was also tested. All strains were found to be sensitive to ampicillin. The tolerance of the strains to low pH, their resistance to bile salts of strains, and their abilities to autoaggregate and coaggregate with Escherichia coli ATCC 11229 were also evaluated. High EPS-producing strains showed significant autoaggregation and coaggregation ability with test bacteria (P < 0.01). A correlation also was determined between EPS production and acid-bile tolerance (P < 0.05). EPS production possibly affects or is involved in acid-bile tolerance and aggregation of Lactobacillus spp., Lactococcus spp., and Pediococcus spp. strains and supports the potential of L. acidophilus Z1L strain as new probiotic.     

Combating biofilms of foodborne pathogens with bacteriocins by lactic acid bacteria in the food industry

Most foodborne pathogens have biofilm-forming capacity and prefer to grow in the form of biofilms. Presence of biofilms on food contact surfaces can lead to persistence of pathogens and the recurrent cross-contamination of food products, resulting in serious problems associated with food safety and economic losses. Resistance of biofilm cells to conventional sanitizers urges the development of natural alternatives to effectively inhibit biofilm formation and eradicate preformed biofilms. Lactic acid bacteria (LAB) produce bacteriocins which are ribosomally synthesized antimicrobial peptides, providing a great source of nature antimicrobials with the advantages of green and safe properties. Studies on biofilm control by newly identified bacteriocins are increasing, targeting primarily onListeria monocytogenes, Staphylococcus aureus, Salmonella, and Escherichia coli. This review systematically complies and assesses the antibiofilm property of LAB bacteriocins in controlling foodborne bacterial-biofilms on food contact surfaces. The bacteriocin-producing LAB genera/species, test method (inhibition and eradication), activity spectrum and surfaces are discussed, and the antibiofilm mechanisms are also argued. The findings indicate that bacteriocins can effectively inhibit biofilm formation in a dose-dependent manner, but are difficult to disrupt preformed biofilms. Synergistic combination with other antimicrobials, incorporation in nanoconjugates and implementation of bioengineering can help to strengthen their antibiofilm activity. This review provides an overview of the potential and application of LAB bacteriocins in combating bacterial biofilms in food processing environments, assisting in the development and widespread use of bacteriocin as a promising antibiofilm-agent in food industries.     

食源性致病菌快速检测技术研究进展

食源性致病菌是影响食品安全的主要问题之一.建立快速的食源性致病菌检测方法对控制农产品和食品从生产、加工、运输、仓储、口岸通关到销售和消费各个环节的生物性风险至关重要.由于传统病原微生物检测耗时长且操作较繁琐,不能及时检测出食品中的病原菌.近年来随着生物技术的快速发展以及对食品安全监测要求的提高,食源性致病菌快速检测方法...     

多种致病菌同步检测方法的研究进展

概述了致病菌检测的对象,包括细菌菌群的形态及细菌本身、细菌的DNA、细菌的代谢物;同时介绍了可同步检测多种致病菌的方法,主要有电化学DNA传感器、适配体电化学传感器、免疫传感器检测技术、多重PCR检测、表面增强拉曼光谱检测;最后总结检测方法未来的发展方向。     

实时荧光定量PCR技术在食源性致病菌检测中的应用

实时荧光定量PCR技术作为一种高效的微生物定量检测法,在食品工业中具有广泛的应用前景。本文综述了实时荧光定量PCR技术检测原理,及其在食源性致病菌如金黄色葡萄球菌、大肠杆菌O157∶H7、沙门氏菌和副溶血性弧菌检测中的应用。     

噬菌体展示技术在食源性致病菌检测中的应用

噬菌体展示技术是20世纪80年代逐步建立并发展起来的一种分子生物学新技术,目前用于构建展示文库的噬菌体主要有丝状噬菌体、λ噬菌体、T4噬菌体和T7噬菌体。该技术在筛选噬菌体、单链抗体及多肽以建立食品安全检测体系方面,具有广阔的应用前景。本文在介绍噬菌体展示技术系统的基础上,对该技术在食源性致病菌检测中的应用进行综述。     

低聚糖拮抗食源性致病菌的研究及应用进展

食源性致病菌导致的食品安全问题已成为世界上重要的公共卫生问题之一,寻找高效且安全的天然抑菌剂引起人们的关注。目前有研究表明低聚糖类物质如果胶低聚糖、低聚壳聚糖、褐藻胶低聚糖等具有较好的抑菌效果,并且低聚糖大多来源于植物胶、甲壳动物,天然海藻多糖等自然物质,对环境污染较小;因此低聚糖能够作为潜在的天然抑菌剂被广泛应用在食品行业中,具有一定的研究意义和应用前景,已经逐渐成为食品行业新的研究热点。该研究综述了几种低聚糖对食源性致病菌的抑菌作用,并分析总结了其抑菌机制：一是低聚糖破坏细菌细胞壁和细胞膜,二是渗入细胞内部破坏蛋白质和核酸物质;同时展望了低聚糖在涂膜保鲜和作为食品添加剂两方面的应用,以期为进一步深入研究低聚糖的作用和在食品行业的应用提供理论参考。     

Variations in Radiation Sensitivity of Foodborne Pathogens Associated with the Suspending Meat

Longissimus dorsi from beef, pork, and lamb and turkey breast and leg meats were inoculated with Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., and Staphylococcus aureus, and the gamma radiation resistance of the pathogens were determined under identical conditions. At 5°C the respective radiation D-values of E. coli O157:H7 and L. monocytogenes did not vary with the suspending meat. The D-value for a mixture of Salmonella spp. was significantly lower on pork than on beef, lamb, turkey breast, and turkey leg meats. The D-value for S. aureus was significantly lower on lamb and mechanically deboned chicken meat than on the other meats. All values were, nevertheless, within expected ranges.     

Lactobacillus kefiranofaciens发酵生产Kefiran多糖的初步研究

研究了发酵条件(温度、起始pH、接种量等)对乳酸菌Lactobacillus kefiranofaciens发酵产Kefiran多糖的影响,并对菌体的形态及发酵特性进行了研究。研究结果表明,菌体形态在生长期间会发生改变,为短杆状-链杆状-短杆状;胞外多糖是从菌体生长期开始合成的;接种量为10%、起始pH为5.3、培养温度为25℃时有利于多糖的合成;CaCO3、Tween80和NaCl的添加量分别为1.2%、4%和0.25%时,胞外多糖的产量可达1.50g/L。     

原料乳中多种致病菌的快速过滤富集及多重PCR检测

针对目前原料乳中致病菌的检测方法繁琐费时耗力的缺点,建立一种能同时检测原料乳中多种致病菌的快速检测方法,采用多重PCR快速灵敏检测技术与一种不需要预增菌就可以直接从原料乳中快速过滤富集菌体的技术相结合来同时检测原料乳中主要致病菌——沙门氏菌、大肠杆菌O157:H7、金黄色葡萄球菌、单增李斯特氏菌和蜡样芽孢杆菌。整个过程只需7～8h即可完成,且检测灵敏度可达102cfu/mL。这种方法是对传统检测方法的有效改进,并且达到了原料乳检测快速、准确、灵敏的要求。     

保加利亚乳杆菌和嗜热链球菌生物膜形成研究

采用置片法和菌落计数法对嗜热链球菌(Streptococcus thermophilus)和保加利亚乳杆菌(Lactobacillus bulgaricus)在不同载体表面(椰果粒、不锈钢网布、塑料片、陶瓷片和玻璃片)上形成生物膜的能力进行研究。结果表明：椰果粒和不锈钢网布是适宜乳酸菌单菌生物膜形成的载体,培养7d椰果粒和不锈钢网布上的单菌生物膜初始菌密度可达107CFU/cm2,并且在后续培养中能稳定在3.2×106CFU/cm2左右;混菌生物膜菌密度连续7d稳定在1×107CFU/cm2左右。利用扫描电镜对S. thermophilus和L. bulgaricus形成的混菌生物膜进行观察,结果表明在椰果粒和不锈钢网布表面上S. thermophilus和L. bulgaricus形成典型的混菌生物膜结构。     

人工模拟胃肠道模型在食源性致病菌异质性研究中的应用进展

探究食源性致病菌在人体胃肠道环境中的异质性以及与肠道菌群间的相互作用对食源性致病菌的控制和预防具有十分重要的意义。人工模拟胃肠道模型基于人体胃肠道的生理过程,在体外条件下模拟体内的消化吸收情况,可以部分或完全替代活体实验,是研究食源性致病菌异质性以及致病机理的一种重要工具。本文系统综述应用人工模拟胃肠道模型研究食源性致病菌在胃肠道中的耐受、耐药异质性,为研究食源性致病菌在人体胃肠道中的异质性提供理论参考,同时将其与食源性致病菌动物感染模型（体内胃肠道模型）进行比较,综合评价人工模拟胃肠道模型在食源性致病菌异质性研究中的应用,以期为构建更加全面、科学的食品安全风险评估体系提供一定指导。     

pH值对乳酸菌生长和乳酸产量的影响

研究了分别用HCl和乳酸调节培养基初始pH以及在发酵过程中加入不同的酸中和剂对乳酸菌生长和乳酸产量的影响。结果表明 ,终产物乳酸的积累是抑制乳酸菌生长和导致乳酸产量下降的直接原因 ,该情况随发酵液中H+浓度的升高 (即pH的降低 )而增强 ,H+的积累对菌体生长和产酸的影响是间接的 ;用CaCO3 调节发酵液pH优于用NaOH和NH4OH。     

食源性致病菌生长延滞期的研究进展

食源性致病菌是引起食源性疾病的首要致病因子,为了定量评估由其引起的食品安全风险、评价食品加工工艺对其控制的有效性,需利用预测微生物学模型估算食源性致病菌的相关生长或失活参数.生长延滞期是描述食源性致病菌生长的重要参数,受多种因素影响,尤其是低菌量水平下细胞生长变异性使得生长延滞期更难以准确获取.本文结合近年来国内外相关...