2017—2021年安徽省食源性腹泻病例病原学分析

目的 分析安徽省2017—2021年食源性腹泻病例病原学特征,为制定相关防控措施提供依据。方法采用横断面研究方法,收集2017—2021年安徽省22家食源性疾病病原学监测医院上报被采集肛拭子/粪便的腹泻病例信息,并按要求对采集的患者标本开展病原学检测。分类资料采用χ_趋势²或χ²进行组间比较。结果 2017—2021年共采集标本15 484份,病原体总检出率为23.75%(3 678/15 484)。其中,诺如病毒检出率最高,为10.01%(1 550/15 484);其次是沙门菌(6.16%,954/15 484)、致泻大肠埃希菌(6.10%,944/15 484)、副溶血性弧菌(1.66%,257/15 484)、志贺菌(1.00%,155/15 484)。不同年份(χ_趋势²=11.249,P<0.05)和不同季度(χ_趋势²=146.119,P<0.05)病原体的检出率,均差异有统计学意义。各年龄段人群中,年龄<1...     

3种流通模式下生猪肉中单增李斯特菌的暴露评估

本研究通过对3 种生猪肉流通模式进行简化,根据生猪肉中单增李斯特菌初始污染水平抽检数据及调研环境参数,评估对比了3 种流通模式下单增李斯特菌在生猪肉中的最终暴露量。结果显示：基于全程非冷链的热鲜猪肉最终阳性检出率约为42.12%,超过风险阈值概率约为21.05%;基于部分冷链的冷鲜猪肉最终阳性检出率约为12.07%,超过风险阈值概率约为1.61%;基于全程冷链的冷鲜猪肉最终阳性检出率约为6.50%,超过风险阈值概率约为0%。相关性分析表明,初始污染水平与最终暴露量Pearson相关系数均为0.70以上,影响最大。因此,冷鲜猪肉较热鲜猪肉更有利于避免食源性疾病的发生,基于全程冷链的冷鲜猪肉应被积极推广。同时在生猪肉供应链中,更应注重源头控制,严格设置并控制各流通环节的环境条件。     

食源性致病菌菌株多相异质性对微生物风险评估的影响研究进展

微生物风险评估是当前保障食品安全的重要科学工具之一,被广泛应用于食品安全政策、法规和标准的制定。菌株多相异质性是微生物的固有特性,普遍存在于各类致病菌之中,影响着风险评估的准确性和不确定性。本文概述了国内外食品微生物菌株多相异质性的相关研究,总结了菌株多相异质性的概念,从生长和失活异质性、被膜形成异质性、毒力异质性和耐药异质性4 个方面全面系统地分析了菌株多相异质性的存在形式。在此基础上探讨了菌株多相异质性对微生物风险评估的影响,进一步展望了降低该影响的4 种解决措施,提出微生物风险评估宏模型的概念,以期提高食品安全风险评估的准确性和可靠性。     

2017年山西省食源性疾病流行病学特征及空间聚集性分析

目的 分析2017年山西省食源性疾病流行病学特征,重点探索其空间聚集情况,为科学地开展防控措施提供依据。方法 运用地理信息系统技术和描述性流行病学方法分析2017年山西省食源性疾病流行病学特征,并运用空间自相关方法研究其空间聚集性。结果 2017年山西省共报告食源性疾病病例27 727例,报告发病率为7.5/万。男女性别比为1.02∶1,20～39岁报告病例数最多(27.6%,7 661/27 727);农民(40.6%,11 266/27 727)、低龄学生(13.2%,3 652/27 727)报告病例数较多。可疑暴露食品主要为水果类及其制品(26.0%,7 207/27 719)、粮食类及其制品(17.9%,4 963/27 719)和肉与肉制品(11.6%,3 207/27 719)。进食场所以家庭为主(73.2%,23 429/31 988)。三维趋势分析得到的疾病报告发病率总体分布情况为:由北向南逐渐升高,由西向东缓慢下降,与报告发病率分布图所呈现的结果一致。食源性疾病报告发病率呈空间正相关,高-高聚集地区为浮山县、隰县、大宁县、永和县、古县、吉县。结论 山西省食源性疾病发病存在明显的空间聚集性。     

单核细胞增生性李斯特菌的增殖和抑制

单核细胞增生性李斯特菌(Listeria Monocytogenes)引起的突发性中毒症是一种很特殊的食物中毒病症.本文阐述了单增李斯特菌的生长特性,包括营养需求、流行病学和溶血素O的一些研究,同时综述了影响李斯特菌增殖的因素,并介绍了一些对食品中单增李斯特菌的抑制方法.     

Ecology of Escherichia coli O157:H7 in commercial dairies in southern Alberta

Shedding of Escherichia coli O157:H7 was monitored monthly over a 1-yr period by collecting pooled fecal pats (FECAL) and manila ropes orally accessed for 4 h (ROPE) from multiple pens of cattle in 5 commercial dairies in southern Alberta, Canada. Using immunomagnetic separation, E. coli O157:H7 was isolated from cows on 4 of the dairies and from 13.5% of FECAL and 1.1% of ROPE samples. Pulsed-field gel electrophoresis of XbaI- and SpeI-digested bacterial DNA of the 65 isolates produced 23 unique restriction endonuclease digestion patterns, although 92% of the isolates belonged to 3 restriction endonuclease digestion pattern clusters sharing a minimum 90% homology. Collection of positive isolates was 15 times more likely from June through September. Across dairies, peak somatic cell count occurred in July, August, September, and November. The likelihood of positive isolates was 2.6 times higher in calves and heifers compared with mature cows. This study indicates that ROPE would be of little value for the detection of E. coli O157:H7 in dairy herds unless oral contact with ROPE could be increased in mature animals. Additionally, mitigation strategies for E. coli O157:H7 should be targeted to the months of July, August, and September and toward immature animals for maximum impact. All farms displayed unique combinations of seasonality of shedding and diversity of E. coli O157:H7 subtypes. The fact that seasonal prevalence of E. coli O157:H7 largely coincided with peak somatic cell count within climatically controlled dairy barns suggests that similar environmental factors may be enhancing fecal shedding E. coli O157:H7 and the incidence of mastitis.     

Phytotoxin Production and Phytoalexin Elicitation by the Phytopathogenic Fungus Sclerotinia sclerotiorum

The fungus Sclerotinia sclerotiorum (Lib.) de Bary causes rot disease in a vast range of plant families, including Cruciferae (Brassicaceae). We investigated the production of phytotoxins by S. sclerotiorum by using a bioassay-guided isolation, as well as the phytoalexins produced by the resistant wild crucifer Erucastrum gallicum under elicitation by S. sclerotiorum and other agents. We established for the first time that S. sclerotiorum produces a somewhat selective phytotoxin, sclerin, which is phytotoxic to three cruciferous species (Brassica napus, B. juncea, and Sinapis alba) susceptible to Sclerotinia stem rot disease, causing severe necrosis and chlorosis, but not to a resistant species (Erucastrum gallicum). In addition, we have shown that oleic acid, the major fatty acid isolated from sclerotia of S. sclerotiorum is responsible for the toxic activity of extracts of sclerotia to brine shrimp larvae (Artemia salina). Phytoalexin elicitation in leaves of E. gallicum led to the isolation of three known phytoalexins: indole-3-acetonitrile, arvelexin, and 1-methoxyspirobrassinin. Considering that resistance of E. gallicum to S. sclerotiorum is potentially transferable to B. rapa, a susceptible canola species, and that arvelexin, and 1-methoxyspirobrassinin are not produced by B. rapa, these phytoalexins may become useful markers for resistance against S. sclerotiorum.     

食源性沙门氏菌分离株自动化核糖体分型的研究

目的:对我国食源性疾病监测网地区鸡肉中分离的沙门氏菌株进行核糖体分型研究。方法:采用自动化核糖体分型方法对2003年和2004年我国不同地区鸡肉中分离的134株沙门氏菌进行核糖体分型,运用BioN-umeric软件对分型结果进行聚类分析,并与常规血清学分型方法进行比较。结果:自动化核糖体分型方法的分型能力相对血清学分型有一定优势,不同地区沙门氏菌分离株间的核糖体型既有一定的联系又呈现出一定的差异化;两年间同一地区分离株的核糖体型呈现出一定的延续性。结论:运用Riboprinter○R对我国134株沙门氏菌分离株进行核糖体分型研究,初步建立了食源性沙门氏菌分子分型数据库。     

Trends in microbial control techniques for poultry products

Fresh poultry meat and poultry products are highly perishable foods and high potential sources of human infection due to the presence of several foodborne pathogens. Focusing on the microbial control of poultry products, the food industry generally implements numerous preventive measures based on the Hazard Analysis and Critical Control Points (HACCP) food safety management system certification together with technological steps, such as refrigeration coupled to modified atmosphere packaging that are able to control identified potential microbial hazards during food processing. However, in recent years, to meet the demand of consumers for minimally processed, high-quality, and additive-free foods, technologies are emerging associated with nonthermal microbial inactivation, such as high hydrostatic pressure, irradiation, and natural alternatives, such as biopreservation or the incorporation of natural preservatives in packaging materials. These technologies are discussed throughout this article, emphasizing their pros and cons regarding the control of poultry microbiota and their effects on poultry sensory properties. The discussion for each of the preservation techniques mentioned will be provided with as much detail as the data and studies provided in the literature for poultry meat and products allow. These new approaches, on their own, have proved to be effective against a wide range of microorganisms in poultry meat. However, since some of these emergent technologies still do not have full consumer's acceptability and, taking into consideration the hurdle technology concept for poultry processing, it is suggested that they will be used as combined treatments or, more frequently, in combination with modified atmosphere packaging.     

Dietary pectic substances enhance gut health by its polycomponent: A review

Pectic substances, one of the cell wall polysaccharides, exist widespread in vegetables and fruits. A surge of recent research has revealed that pectic substances can inhibit gut inflammation and relieve inflammatory bowel disease symptoms. However, physiological functions of pectins are strongly structure dependent. Pectic substances are essentially heteropolysaccharides composed of homogalacturonan and rhamnogalacturonan backbones substituted by various neutral sugar sidechains. Subtle changes in the architecture of pectic substances may remarkably influence the nutritional function of gut microbiota and the host homeostasis of immune system. In this context, developing a structure–function understanding of how pectic substances have an impact on an inflammatory bowel is of primary importance for diet therapy and new drugs. Therefore, the present review has summarized the polycomponent nature of pectic substances, the activities of different pectic polymers, the effects of molecular characteristics and the underlying mechanisms of pectic substances. The immunomodulated property of pectic substances depends on not only the chemical composition but also the physical structure characteristics, such as molecular weight (M_w) and chain conformation. The potential mechanisms by which pectic substances exert their protective effects are mainly reversing the disordered gut microbiota, regulating immune cells, enhancing barrier function, and inhibiting pathogen adhesion. The manipulation of pectic substances on gut health is sophisticated, and the link between structural specificity of pectins and selective regulation needs further exploration.