Induction,detection, formation,and resuscitation of viable but non‐culturable state microorganisms

The viable but nonculturable (VBNC) state has been recognized as a strategy for bacteria to cope with stressful environments; in this state, bacteria fail to grow on routine culture medium but are actually alive and can resuscitate into a culturable state under favorable conditions. The VBNC state may pose a great threat to food safety and public health. To date, more than 100 VBNC microorganism species have been proven to exist in fields of food safety, environmental application, and agricultural diseases. Most harsh conditions can induce these microorganisms into the VBNC state, including food processing and preservation methods, adverse environmental conditions, and plant‐disease controlling means. The characteristics of VBNC state cells differ from those of normally growing cells and dead cells, based on which of the various detection methods are developed, and they are of great significance for potential risk assessment. To provide molecular level insights into this state, many studies on induction and resuscitation mechanisms have emerged over the past three decades, including research on omics, specific genes, or proteins involved in VBNC state formation and the roles of promoters in resuscitation from the VBNC state. In this review, microorganism species, induction and resuscitation factors, detection methods, and formation and resuscitation mechanisms of the VBNC state are comprehensively and systematically summarized.     

预制菜企业微生物污染状况及影响因素分析

目的 了解预制菜生产中的微生物污染状况,为预制菜企业的卫生控制提供参考,并为相关产品卫生规范及标准的制定提出建议。方法 从湖南省70家预制菜企业中等比例分层抽样5家,对其生产加工过程中的环境空气沉降菌及接触表面、邻近接触表面、预制菜样品中大肠菌群和菌落总数进行检测。结果 中型企业的环境空气沉降菌及各表面、预制菜样品中大肠菌群和菌落总数较高(P＜0.05),预制蔬菜制品生产车间各表面菌落总数较高(P＜0.05),接触表面中加工人员手部更易受微生物污染(P＜0.05),差异均有统计学意义;预制蔬菜制品菌落总数较高(P＜0.05),过程产品大肠菌群、菌落总数均高于成品(P＜0.05),差异均有统计学意义。结论 预制菜企业尤其是中型企业,应加强预制蔬菜制品生产车间的卫生要求及过程产品的卫生控制;建议相关产品标准及产品生产卫生规范中应注重车间卫生管理及生产过程的卫生控制。     

沙门氏菌快速检测板在食品检测中的应用研究

目的研究沙门氏菌快速检测板在食品检测中的应用。方法以标准菌株为测试样本,参照GB4789.4-2010验证沙门氏菌快速检测板的灵敏度、特异性、假阳性率、假阴性率、准确度,同时利用卡方检验分析阳性率显著性差异。结果沙门氏菌快速检测板最低检测限能达到10~0 CFU/m L,灵敏度为100%,不存在假阴性,特异性为92%,假阳性率为8%,准确度为95%,显著性差异卡方值卡Χ~2为0.5,均达到定性方法验证的相关指标。结论沙门氏菌检测板技术方法具有快速准确、灵敏度高、操作简单的特点,可以作为一种快速筛查方法广泛运用在食品安全微生物检测领域。     

2010—2019年全国细菌性食物中毒事件流行病学特征分析

目的 了解我国细菌性食物中毒发生规律及流行特点,探讨其空间聚集性,为预防和控制细菌性食物中毒事件提供措施建议。方法 采用描述性流行病学方法对2010—2019年全国细菌性食物中毒事件进行分析比较,采用Arcgis 10.6软件对数据进行空间自相关分析并绘制相关地图。结果 2010—2019年突发公共卫生事件管理信息系统共报告细菌性食物中毒事件1 110起,中毒49 457例,死亡87例。第三季度是细菌性食物中毒的高发季节,9月是细菌性食物中毒的高发月份。在查明原因的事件中,肉与肉制品污染引起的事件数（19.10%）最多。非伤寒沙门菌、副溶血性弧菌和蜡样芽胞杆菌是引起细菌性食物中毒的主要致病因素,分别占事件总数和中毒总人数的56.04%和61.17%。发生在集体食堂的细菌性食物中毒事件数（39.46%）和中毒人数（34.79%）最多,发生在家庭的细菌性食物中毒事件死亡人数最多（83.91%）。广东、四川、云南、广西、山东等地报告的事件数和中毒人数居全国前5位,细菌性食物中毒事件在空间上呈现集聚性分布,热点地区主要分布于云南省大部分地区,广西西部及北部、四川省南部、重庆市、湖北省西部及北部、湖南省西部及南部、广东省中部及北部。结论 我国细菌性食物中毒事件中毒人数、事件起数居于各类食物中毒事件首位,建议相关部门在重点时段,对集体食堂、餐饮服务单位等重点场所加强监管,严格落实各项食品安全标准及要求,对重点人群加强宣传教育。建议细菌性食物中毒热点地区探索其空间聚集性的形成原因及机制,采取相对应措施减少细菌性食物中毒事件的发生。     

低水分调味料带菌状况及控制技术的研究进展

总结了低水分调味料带菌状况的研究进展,并对几种常用的灭菌方法在低水分调味料带菌状况控制中的应用进行了综述。     

2018—2021年广州市白云区网络外卖食品微生物污染状况监测分析

目的 了解广东省广州市白云区网络外卖食品安全风险,为完善广州市外卖食品安全保障体系提供科学依据。方法 2018—2021年在广州市白云区采集174份网络外卖食品,依据《食品安全国家标准食品微生物学检验》（GB 4789）对样品中菌落总数、大肠埃希菌、沙门菌、金黄色葡萄球菌、单核细胞增生李斯特菌、蜡样芽胞杆菌、副溶血性弧菌进行培养和鉴定。结果 2018—2021年监测样品总体不合格率为20.1%(35/174),其中菌落总数和大肠埃希菌不合格率较高,不同年度的不合格率及不同类别食品的不合格率差异具有统计学意义（P<0.05）。单因素分析发现不同室外湿度、不同食品中心温度样品的合格率组间差异具有统计学意义（P<0.05）。多因素Logistic回归分析发现,食物中心温度越高（OR=0.917,95%CI:0.876～0.960）,食品不合格率越低;对不同品种的外卖食品进行组间比较发现,以米饭加菜类为参照组,凉拌菜类（OR=0.010,95%CI:0.001～0.159）、寿司手卷类（OR=0.041,95%CI:0.002～0.771）的不合格率更低（P<0.05）。结论...     

一起由沙门氏菌和金黄色葡萄球菌混合引起的食物中毒病原分析

目的对引起食物中毒相关样品进行病原菌的分离、鉴定和耐药分析。方法参照GB 4789系列标准的方法流程对采集的食物样本进行沙门氏菌、金黄色葡萄球菌、志贺氏菌、副溶血弧菌和单核细胞增生李斯特氏菌共5项致病菌指标检测,按照纸片扩散法(K-B法)进行药敏实验。结果从食物中毒样品中检出肠炎沙门氏菌、金黄色葡萄球菌,确定为二者混合感染引起的食物中毒。药敏结果显示肠炎沙门氏菌对多数抗生素敏感,金黄色葡萄球菌耐药性强,对链霉素、头孢噻肟、氯霉素、红霉素有一定的耐药性。结论本起事件是由肠炎沙门氏菌和金黄色葡萄球菌混合感染引起的食物中毒事件,建议食品卫生监管人员应加强对餐饮环节的监督引导,避免类似事件发生。     

Occurrence and survival of Campylobacter spp. in dairy matrices investigated by viability qPCR

The aim of this study was to investigate the survival of Campylobacter jejuni in dairy matrices by viability qPCR. Survival in UHT milk was examined first and the cheese outbreak strain, C. jejuni 11 218 showed enhanced tendency to become viable but nonculturable (VBNC). It survived for long at different pH values, in raw and fermented milk and cheese. Viability qPCR was also used to examine the occurrence of viable Campylobacter spp. in raw milk, detecting the bacteria in 40.9% of 25 mL samples negative on culture. Results showed that viability qPCR is valuable in estimating Campylobacter risk in dairy products.     

Modelling the Growth of Salmonella spp. and Escherichia Coli O157 on Lettuce

This study aimed to model the growth of Salmonella and Escherichia coli O157 on lettuce at different temperatures. Microorganisms were inoculated separately on lettuce and stored at 5, 10, 25, and 37°C. Growth curves were built by fitting the data to the Baranyi's DMFit model and Ratkowsky equation was used as secondary model. The models were able to assess the growth of both microorganisms and data showed that bacteria did not growth for 24hours at 10°C, what can be a suitable temperature for lettuce distribution on food services. However, prolonged periods demonstrated growth at every temperatures examined.     

2004—2012年分离自北京口岸进出口食品的沙门菌耐药性分析

目的 了解北京口岸进出口食品中分离沙门菌的耐药状况及耐药谱情况,分析耐药趋势,为制定食品安全监管措施和抗生素的使用提供依据。方法 对65株本实验室分离的沙门菌以及17株参比菌株,共82株沙门菌采用Kindy-Bauer(KB)法检测其对15种抗生素的敏感性,根据美国临床实验室标准化研究所(CLSI)标准进行判断,并对药敏试验结果进行数据分析。结果 65株沙门菌分离株除对头孢吡肟、头孢曲松、阿米卡星、头孢噻肟全部敏感外,对其余11种抗生素均有不同程度的耐药,其中氨苄西林耐药率最高为16.9%(11/65),其次为哌拉西林(13.8%,9/65)、四环素(13.8%,9/65)、卡那霉素(9.2%,6/65)和链霉素(7.7%,5/65)。在所有65株沙门菌分离株中,对1种抗生素耐药的菌株共11株,占16.9%(11/65),对2种抗生素耐药的菌株为1株,占1.5%(1/65),对3种及以上抗生素耐药的多重耐药株为7株,多重耐药率为10.8%(7/65)。结论 北京口岸进出口食品中分离的沙门菌对多种抗生素耐药。     

上海市2011~2015年保健食品中铅、砷、汞污染 状况分析及评价

目的 采用新、旧两版GB 16740标准对上海市保健食品中铅、砷、汞残留量进行分析与评价, 了解重金属污染状况及评价标准改变带来的变化。方法 采用国家标准规定的检测方法, 对2011~2015年上海市收检的保健食品进行铅、砷和汞残留量测定, 并使用SPSS 19.0对测定结果进行统计分析。结果 上海市2011~2015年共检测保健食品7306份, 按旧版GB 16740评价, 总合格率为96.17%, 铅、砷和汞残留量总超标率分别为3.09%、1.46%和0.22%; 按新版GB 16740评价, 总合格率为98.06%, 铅、砷和汞残留量总超标率分别为1.28%、0.94%和0.22%, 超标样品中胶囊剂和茶剂居多。结论 上海市保健食品中铅、砷、汞污染水平总体较低, 新版的评价标准改变了原标准中根据剂型判断结果的模式, 使得结果评价更为合理。     

食品及销售环境中枸橼酸杆菌污染状况及耐药谱分析

目的 了解石家庄市食品以及销售环境中枸橼酸杆菌的污染状况和菌株耐药情况,为预防由该菌引起的食源性疾病及临床治疗用药提供科学依据.方法 采集石家庄市内4区以及周边4县(区)的超市及农贸市场的生畜肉、生禽肉、动物性水产品、熟食,对4类食品以及销售环境样品进行枸橼酸杆菌分离检测,并对分离株进行耐药检测.菌株鉴定应用飞行时间质...     

2008—2010年全国突发公共卫生事件网络报告食物中毒流行病学分析

目的 分析2008-2010年我国“突发公共卫生事件报告管理信息系统”报告的食物中毒.方法 对2008-2010年中国突发公共卫生事件报告管理信息系统收到的所有食物中毒事件进行描述性分析.结果 2008-2010年全国共报告食物中毒1 218起,中毒35 672例,死亡518例,病死率为1.45％.报告事件高峰在6-10月,其中9月最多.致病因素依次为不明原因480起,微生物类320起,植物类279起,化学类122起,动物类17起.结论 全国突发公共卫生事件报告的食物中毒中,中毒起数和发病人数最多的是微生物所导致食物中毒;而毒蘑菇、农药/鼠药是导致食物中毒事件中中毒者死亡的主要原因.     

苏州某市一起肠炎沙门氏菌食物中毒事件调查分析

目的用现场流行病学方法,分析本次食物中毒事件的原因和可疑危险因素,指导临床救治并提出预防措施。方法通过查阅医院就诊记录和医务室门诊记录、考勤记录、员工订餐记录等主动搜索病例,开展病例个案调查和现场卫生学调查,采集相关样品进行实验室检测等,判断引起本次食物中毒事件的可疑餐次和食物。结果通过访谈、个案调查、实验室检查等共搜索到可能病例67人(包括确诊病例27人),临床特征主要为腹泻(83.58%,56/67)、发热(79.10%,53/67)、腹痛(76.12%,51/67)等。可疑食品是3月3日晚餐的回锅肉,59份肛拭子分离到25份肠炎沙门氏菌,其中一株分离自厨师。经脉冲场电泳(pulsed-fieldgel electrophoresis, PFGE)分型, 25株肠炎沙门氏菌同源性为100%。经药敏分析显示, 25株肠炎沙门氏菌对头孢噻肟、头孢他啶具有较好的药物敏感性;对氨苄西林、氯霉素耐药性强。结论食用被肠炎沙门氏菌污染的回锅肉是导致本次事件的主要原因,建议监管部门加强对集体配餐单位的监督管理,提高从业人员食品安全意识,防范类似事件的发生。     

舟山市一起肠炎沙门菌污染三明治引起食物中毒事件调查

目的 对不同学校发生的一起食物中毒事件开展流行病学调查,分析致病因子和污染来源,指导临床救治并提出预防措施。方法 通过调查病例临床特征和流行病学分布,结合实验室脉冲场凝胶电泳(PFGE)技术,对不同来源的沙门菌进行同源性分析,同时利用微量肉汤稀释法进行药敏试验。结果 此次事件涉及不同区县的4所学校,共发现疑似病例37例,确诊19例,病例临床特征主要为腹泻(70.27%,26/37)、发热(54.05%,20/37)、腹痛(51.35%,19/37)、呕吐(37.84%,17/37)等。实验室共分离肠炎沙门菌24株,其中19株来自病例,5株来自可疑食品三明治及其原料肉松。经PFGE分型,24株肠炎沙门菌聚类结果为100.00%。经药敏显示,19株病例株对萘啶酸耐药率为100.00%,对头孢西丁和亚胺培南耐药率均为5.26%(1/19)。结论 结合临床表现、流行病学调查、实验室检测结果,证实三明治原料肉松被肠炎沙门菌污染是导致本次事件的主要原因,建议监管部门加强对学校配餐公司的监督管理,提高公司从业人员食品安全意识,防范此类事件的发生。     

Review of micro- and nanoplastic contamination in the food chain

Whereas the dramatic environmental impact of plastic waste rightfully receives considerable attention by scientists, policy makers and public in general, the human health impact of micro- and nanoplastics contamination of our food and beverages remains largely unknown. Indeed, most studies aim at understanding the environmental impact rather than the human health impact of a possible exposure to micro- and nanoplastics. In addition, these papers generally lack a methodological, standardised approach. Furthermore, some studies focus on the damage to and contamination level of animal species collected from the wild environment, and others investigate the rate and biology of microplastic uptake of animals fed with microplastics in laboratory. This review aims at understanding human exposure. Since there is, with few exceptions, no evidence available on the presence of micro- and nanoplastics in a normal diet, this study takes an indirect approach and analyses peer-reviewed publications since 2010 that document the presence of micro- and nanoplastics in those animals (more than 200 species) and food products that are part of the human food chain and that may thus contribute directly or indirectly to the uptake of micro- and nanoplastics via the human diet. It also addresses the question of the definitions, the methodologies and the quality criteria applied to obtain the reported results. This review suggests that, beyond a few estimations and comparisons, precise data to assess the exact exposure of humans to micro- and nanoplastics through their diet cannot be produced until standardised methods and definitions are available.     

Beyond water activity: recent advances based on an alternative approach to the assessment of food quality and safety.

Water, the most abundant constituent of natural foods, is a ubiquitous plasticizer of most natural and fabricated food ingredients and products. Many of the new concepts and developments in modern food science and technology revolve around the role of water, and its manipulation, in food manufacturing, processing, and preservation. This article reviews the effects of water, as a near-universal solvent and plasticizer, on the behavior of polymeric (as well as oligomeric and monomeric) food materials and systems, with emphasis on the impact of water content (in terms of increasing system mobility and eventual water "availability") on food quality, safety, stability, and technological performance. This review describes a new perspective on moisture management, an old and established discipline now evolving to a theoretical basis of fundamental structure-property principles from the field of synthetic polymer science, including the innovative concepts of "water dynamics" and "glass dynamics". These integrated concepts focus on the non-equilibrium nature of all "real world" food products and processes, and stress the importance to successful moisture management of the maintenance of food systems in kinetically metastable, dynamically constrained glassy states rather than equilibrium thermodynamic phases. The understanding derived from this "food polymer science" approach to water relationships in foods has led to new insights and advances beyond the limited applicability of traditional concepts involving water activity. This article is neither a conventional nor comprehensive review of water activity, but rather a critical overview that presents and discusses current, usable information on moisture management theory, research, and practice applicable to food systems covering the broadest ranges of moisture content and processing/storage temperature conditions.     

Prevalence,Distribution, and Diversity of Salmonella spp. in Meat Samples Collected from Italian Slaughterhouses

Recently worldwide food safety authorities indicated the rise of foodborne outbreaks linked to Salmonella: this highlighted the need to intensify monitoring and apply more targeted controls to help manage the spread of the disease. The aim of this study was to assess the prevalence and distribution of Salmonella serotypes in 7 slaughterhouses, located in different areas of Naples province (Regione Campania, Italy). Meat samples collected from the slaughterhouses were submitted for standardized microbiological analysis in 2015. Results of routine testing for Salmonella spp. were analyzed and then compared to biochemical and molecular evaluations. Salmonella spp. were detected in 12% of 320 samples examined (39/320) and the isolation rates ranged from 87% (32 samples) for raw poultry meat to 13% (7 samples) for pork meat. Biochemical serotyping showed that approximately 50% of the isolates belonged to Salmonella enterica serotype Choleraesuis. Rapid detection methods, such as molecular analysis (polymerase chain reaction and gel electrophoresis), able to confirm food matrices contamination, represent a valid support to the fast identification of Salmonella species. A further aspect of the study consisted, indeed, on analyzing isolated strains through molecular evaluations. By amplifying bacterial DNA—using invA primers, selective for Salmonella—it was possible, in less than 3 h, to classify the isolates as Salmonella spp., confirming the results of microbiological outcomes. Results of distribution analysis, supported by rapid molecular approaches, showed the difficulty of reducing Salmonella risk on food chain. This emphasized the importance of periodic surveillance to prevent outbreaks.     

Occurrence and characterization of Listeria spp. in ready-to-eat retail foods from Vancouver, British Columbia

The occurrence of Listeria spp. and Listeria monocytogenes in retail RTE meat and fish products in Vancouver, British Columbia (B.C.) was investigated. To assess potential consumer health risk, recovered L. monocytogenes isolates were subjected to genotypic and phenotypic characterization. Conventional methods were used to recover Listeria spp. from deli meat (n = 40) and fish (n = 40) samples collected from 17 stores. Listeria spp. were recovered only from fish samples (20%); 5% harboured Listeria innocua, 5% had L. monocytogenes and 10% contained Listeria welshimeri. L. monocytogenes isolates serotyped as 1/2a and 1/2b, possessed dissimilar PFGE patterns, and had full-length InlA. Three 1/2a clonal isolates encoded the 50 kb genomic island, LGI1. Antimicrobial resistance (AMR) profiling showed all Listeria spp. possessed resistance to cefoxitin and nalidixic acid. L. monocytogenes were resistant to clindamycin, two were resistant to streptomycin, and one to amikacin. Reduced susceptibility to ciprofloxacin was seen in all L. monocytogenes, L. innocua and three L. welshimeri isolates. Reduced susceptibility to amikacin and chloramphenicol was also observed in one L. monocytogenes and three L. welshimeri isolates, respectively. Recovery of L. monocytogenes in fish samples possessing AMR, full-length InlA, LGI1, and serotypes frequently associated with listeriosis suggest B.C. consumers are exposed to high-risk strains.