江苏省徐州市市售发酵与非发酵豆制品微生物污染调查

目的 调查江苏省徐州市市售豆制品微生物污染情况。方法 采集发酵、非发酵豆制品86份, 按照GB 4789进行大肠菌群、菌落总数(非发酵豆制品)、蜡样芽胞杆菌、金黄色葡萄球菌的定量和单核细胞增生李斯特氏菌、沙门氏菌的定性检测。结果 大肠菌群检出率为34.88%, 蜡样芽胞杆菌为12.79%, 金黄色葡萄球菌为1.16%, 其余致病菌均未检出。非发酵豆制品中大肠菌群检出率为65.91%, 计数>103 CFU/g占52.27%, 散装较预包装样品检出率高, 差异有显著意义(P<0.05); 菌落总数>105 CFU/g占75.00%; 蜡样芽胞杆菌检出率为6.82%, 104 CFU/g(均<105 CFU/g)占4.55%; 金黄色葡萄球菌检出率为2.27%。发酵类豆制品中大肠菌群检出率为2.38%, 蜡样芽胞杆菌为19.05%, 104 CFU/g占7.14%(均<105 CFU/g); 预包装、散装样品蜡样芽胞杆菌检出率差异无显著意义(P>0.05)。发酵、非发酵豆制品中大肠菌群检出率差异均有显著意义(P<0.05); 发酵豆制品合格率为97.62%, 非发酵豆制品合格率为11.36%, 差异有显著意义(P<0.05)。结论 徐州市豆制品中非发酵类卫生指标菌污染较为严重, 应加强卫生监督。     

肉牛屠宰过程中胴体表面及接触环境污染情况分析

为研究肉牛屠宰场屠宰过程中牛胴体表面污染及接触环境污染变化情况,选取某牛屠宰场采集样品共计322 份,分别在剥皮扯皮、去内脏、修整称质量、冲洗及排酸环节对牛胴体后腿、背部、胸部、前腿及颈部以及屠宰前后的工人手部及刀具进行采样,测定菌落总数、乳酸菌、大肠菌群、金黄色葡萄球菌及假单胞菌的污染情况。结果表明：胴体表面污染情况总体呈现先上升后下降的趋势,修整称质量环节污染最为严重,菌落总数可达到2.82（lg（CFU/cm2））;胸部为屠宰过程中污染最严重的部位,平均菌落总数可达到2.10（lg（CFU/cm2））;屠宰空气在冲洗时污染最为严重,空气沉降菌落总数高达271.33 CFU/皿;屠宰工人的手部及刀具也是胴体污染的主要来源。     

景迈山虫茶菌相及卫生微生物指标的检测分析

目的评价景迈山虫茶的食用安全性。方法根据《食品卫生微生物学检验》的办法,对景迈山虫茶的菌落总数、大肠菌群、霉菌、致病菌(志贺氏菌、沙门氏菌、金黄色葡萄球菌、溶血性链球菌)等卫生微生物指标进行检测。结果虫茶中的菌落总数为3.30 CFU/g,大肠杆菌数为24.1 MNP/100 g,霉菌数为3.50 CFU/g,致病菌均未检出。全微生物分离纯化出55个菌株,其中真菌30株,细菌25株,未发现有害菌株。景迈山虫茶各项卫生微生物指标均符合GB/T 4789.2-2010等标准。结论景迈山虫茶作为一类新资源食品,在卫生微生物学方面是安全的。     

自贡冷吃兔生产环境中细菌的鉴定及溯源分析

利用自然沉降法和涂抹采样法对自贡冷吃兔生产环境进行微生物监测,采用传统培养法结合16Sr DNA测序技术鉴定,确定生产环境中细菌的主要种属,建立潜在污染细菌库,最后通过构建系统发育树进行溯源分析。本次研究从生产环境中共分离出61株菌,分别属于21个属;生产车间空气、生产人员、设备与器具均检出不动杆菌属细菌,其次为气单胞菌属、假单胞菌属和葡萄球菌属;冷吃兔辅料处理间、辅料储存间、炒制间、冷却间、内包装间的菌落总数在生产过程中变化较小,原料处理间受人员操作影响变化较大。通过研究发现不动杆菌属在自贡冷吃兔生产环境中分布广泛;冷吃兔加工设备器具表面和人员手部是冷吃兔产品潜在的污染来源;真空包装冷吃兔腐败样品中芽孢杆菌属细菌主要来源于各生产车间空气微生物,葡萄球菌属细菌主要来源于炒制人员以及炒制间空气微生物。本研究深入了解了自贡冷吃兔生产环境的污染情况并能为其风险控制提供一定的科学依据。     

2017年楚雄地区餐饮业过桥米线微生物污染状况调查分析

目的 了解楚雄地区过桥米线微生物污染状况, 获得地域代表性数据。方法 按照《2017年云南省食品安全风险监测方案》, 采用国家标准规定的检测方法, 对60份过桥米线样品进行菌落总数、大肠菌群、霉菌计数、沙门氏菌、蜡样芽胞杆菌、变形杆菌、金黄色葡萄球菌、单核细胞增生李斯特杆菌8个微生物指标检测。结果 60份过桥米线样品中,菌落总数检出率83.33%(50/60), 大肠埃希氏菌计数检出率40.00%(24/60), 霉菌计数检出率65.00%(39/60); 致病菌总检出率33.33%(20/60), 共检出食源性致病菌23株, 检出菌株数(检出率)分别是: 蜡样芽胞杆菌9株(15.00%)、金黄色葡萄球菌6株(10.00%)、变形杆菌5株(8.33%)、沙门氏菌3株(5.00%), 单核细胞增生李斯特杆菌未检出。结论 楚雄地区过桥米线微生物污染严重, 应加强监管, 控制食用安全风险; 同时应尽快制定云南省地方特色食品过桥米线的食品质量或安全标准。     

多种不同方法对微生物能力验证样品测试结果的比较及分析

目的在检测实验室能力验证样品时,通过多种方法进行比较,提高检测能力和结果准确性。方法菌落总数依据国标方法,在相同条件下由不同操作人员重复测定共10次,通过测量结果的不确定度的评定确定置信区间。大肠菌群通过3种方法计数,用大肠杆菌/大肠菌群测试片对大肠埃希氏菌进行快速定性判定。金黄色葡萄球菌通过不同培养基、涂布量、接种方法的7种不同组合方法进行检测。结果本次能力验证结果报告菌落总数结果为23000 CFU/mL、大肠菌群结果为10000 CFU/mL、金黄色葡萄球菌结果为12000 CFU/mL、大肠埃希氏菌检出。4项测试结果均为满意。结论通过多种方法同步进行,能有效提高检测能力和结果准确性。     

包装饮用水生产工艺中微生物风险分析

本研究在A、B、C、D四个市的包装饮用水产工艺中的微生物进行调查,获得微生物污染的基础数据,评价企业生产工艺中微生物污染控制系统的有效性。全面对四个工厂生产工艺过程中原水、过程水及成品水进行微生物检测,利用传统和分子方法对优势菌进行菌种鉴定。结果显示,33份样品霉菌和酵母计数、大肠菌群检出值均1 CFU/mL,砂滤水和碳滤水的菌落总数均有检出,且检出值较高。过程水中的产气荚膜梭菌均未检出,其中碳滤水有检出粪链球菌,反渗透(Reverses Osmosis,RO)水有检出铜绿假单胞菌。共分离到34株细菌,优势菌包括食酸菌属、假单胞菌属、分枝杆菌属和芽胞杆菌属。包装饮用水企业生产工艺对微生物的控制较为有效,微生物危害风险较低。议包装饮用水企业建立生产现场微生物识别系统,加强微生物监控,掌握生产过程中的微生物风险,为合理有效地控制生产工艺中微生物风险提供科学依据。     

95℃水雾炖煮工艺条件下燕窝制品微生物安全风险评价

为了研究95℃水雾炖煮工艺对燕窝制品生产过程中微生物的消减效果,并评价产品储藏和运输过程中微生物的安全性,测定了炖煮前后样品微生物数量变化以及在不同贮藏和运输温度下燕窝产品中微生物菌落数量变化规律,并通过分子生物学方法鉴定燕窝成品加速腐败样品中所分离微生物的种类。结果显示, 95℃水雾炖煮条件下微生物杀菌效果最高可达5 lg (CFU/g),在低于8℃温度条件下贮存20 d内,燕窝成品中菌落总数均≤1 lg (CFU/g),大肠菌群<10 MPN/g,沙门氏菌未检出/25 g,金黄色葡萄球菌和霉菌均<10 CFU/g。另外,燕窝成品加速试验中微生物培养分纯菌株分子鉴定结果显示,燕窝产品加速试验中的微生物为芽孢杆菌属和葡萄球菌属细菌。经系统发育分析,所分纯微生物为弯曲芽孢杆菌、巨大芽孢杆菌、南海假芽孢杆菌和沃氏葡萄球菌,该类细菌通常情况下不会引起人类或者动物疾病,分析结果间接证明了水雾炖煮燕窝在生产过程中的安全性。此研究有利于了解水雾炖煮工艺在燕窝生产中应用的安全性,并为保障低温灭菌短保质期燕窝品质安全提供理论依据。     

羊糕卫生检测结果分析

为了搞好羊糕的卫生监督监测,保证其卫生质量,通过对南京市20个卤莱店的羊糕抽样进行大肠菌群、菌落总数和致病菌等微生物指标进行检测,每店抽样两份共40份样本。结果表明羊糕的总合格率为0。其中大肠菌群不合格率为100％,菌落总数超标率为45％,金黄色葡萄球菌、沙门氏菌和副溶血性弧菌等致病菌均未检出。     

经辐照杀菌的无菌袋中耐辐照微生物分离与鉴定

对某番茄酱生产企业提供的辐照杀菌（辐照剂量≥15 kGy）的5 L无菌袋进行菌落计数、分离和鉴定。3 L无菌水反复漂洗,滤膜过滤后进行平板菌落计数,分离纯化后采用16S rDNA和dnaJ序列分析分别鉴定到属和种。结果表明,5 批次的样品中均有细菌检出,数量在5～132 CFU/袋,9 个典型菌落经过16S rDNA序列分析后,分别属6 个属,其中栖水菌属（Enhydrobacter）、不动杆菌属（Acinetobacter）和考克斯菌属（Kocuria）各1 株,微球菌属（Micrococcus）、微杆菌属（Microbacterium）和芽孢杆菌属（Bacillus）各2 株;dnaJ序列分析则将一株葡萄球菌C8-3鉴定到种-表皮葡萄球菌（Staphylococcus epidermidis）。辐照杀菌的无菌袋虽然微生物数量不高,但是依然残留了一些耐辐照的细菌,它们或多或少会给内装食品带来一定的食品安全隐患或影响食品保质期。     

浙江玫瑰醋异常发酵微生物的鉴定及控制途径探索

为探究浙江玫瑰醋异常发酵的原因,从异常发酵玫瑰醋的表面膜醭分离菌株,并通过回接实验考察其发酵特征,采用形态观察、分子生物学技术对其进行鉴定,并探讨其发酵特性及控制途径。结果表明,分离到4株细菌和2株真菌,均有异常发酵特征,其中接种菌株X-4的醋样出现明显的发酵臭味,而接种菌株Z-1和Z-2的醋样表面形成膜醭。经鉴定,4株细菌分别为类芽孢杆菌（Paenibacillus sp.）、金黄色葡萄球菌（Staphylococcus aureus）、表皮葡萄球菌（Staphylococcus epidermidis）、蜡状芽孢杆菌（Bacillus cereus）,2株真菌分别为库德里阿兹威毕赤酵母（Pichia kudriavzevii）和盔形毕赤酵母（Pichia manshurica）。低温是异常发酵微生物成为优势菌的前提条件,毕赤酵母产生的膜醭阻断了醋酸菌的氧气供应是导致醋酸异常发酵的主要因素。一旦玫瑰醋发生异常,应及时翻缸、升高温度、加入醪液。     

A preliminary evaluation of the effect of glove use by food handlers in fast food restaurants

A study was conducted to determine whether the levels of selected microorganisms differed on foods handled by gloved and bare hands at fast food restaurants. Three hundred seventy-one plain flour tortillas were purchased from fast food restaurants and analyzed for Staphylococcus aureus, Escherichia coli, Klebsiella sp., coliform bacteria, and heterotrophic plate count bacteria. Approximately 46% of the samples were handled by workers wearing gloves compared with 52% of samples with bare hand contact. Coliform bacteria were found in 9.6% of samples handled by gloved workers and 4.4% of samples handled by bare hands, although this difference was not statistically significant. The distribution of heterotrophic plate count bacteria, a general measure of hygiene, was also higher in samples handled by gloved workers in one restaurant chain. The presence of E. coli, Klebsiella sp., and S. aureus was detected in one, two, and eight samples, respectively, and there were no significant differences between samples handled by gloved or bare hands. Neither direct contact of the tortilla with the food preparation surface nor gender of the worker affected the level of any organism tested. The observed tendency of food workers to wear the same pair of gloves for extended periods and complacency might account for the apparent failure of gloves to reduce or prevent bacterial contamination. The results further suggest that glove use might be counterproductive because workers might wash their hands less frequently when gloved.     

Microbial Assessment in School Foodservices and Recommendations for Food Safety Improvement

ABSTRACT:  This study evaluated microbial food safety in school foodservices. Five school foodservices were randomly selected, and samples from water, cooking utensils, tableware, foodservice surroundings, and linen were collected in summer and winter ( N = 420). Tap and drinking water samples were collected, samples of food contact surfaces were collected by swab-kit, and samples for foodservice workers' hands and gloves were prepared by glove juice method. Aerobic plate count (APC) and coliform bacterial populations were enumerated on plate count agar (PCA) and desoxycholate lactose agar, respectively. The presence of Escherichia coli , Salmonella , Listeria monocytogenes , and Staphylococcus aureus was also examined by biochemical identification tests. In addition, PCA agar for APCs and Baird-Parker agar for S . aureus were used to enumerate airborne microorganisms. Higher APCs (< 0 to 5.1 log CFU/mL) than acceptable level were generally observed in water samples, while low coliform counts were found in the samples. High APCs were enumerated in cooking utensils, foodservice workers, tableware, and foodservice surroundings, and coliforms were also found in the samples for both seasons. The presence of Salmonella was found from only 10% of plastic glove samples (summer), and the presence of L . monocytogenes was not observed in all samples. S . aureus was detected in some of water, cooking utensils, tableware, employees, and foodservice surroundings, and E . coli was observed in cooking utensils (10% to 20%; summer). No obvious airborne bacteria were detected. These results showed that sanitation practice in school foodservices should be improved, and the results may be useful in microbial assessment of school foodservices.     

生猪肉加工厂食品接触面四环素耐药菌及其耐药基因的分布

耐药菌的传播会对食品安全与人类健康造成严重威胁。本研究通过对某大型生猪肉加工厂食品接触面污染微生物四环素耐药情况进行分析,探讨其对生猪肉制品质量与安全的潜在危害。从生猪加工厂食品接触面共采集样品100份,共分离到168株细菌。通过药敏试验,发现60.7%的污染细菌对四环素具有耐药性,包括85.7%的假单胞菌属、85.7%的葡萄球菌属、86.7%的沙雷氏菌属、80%的乳球菌属、80%的大肠杆菌、60.0%的不动杆菌属和55.0%的气单胞菌属。通过对分离株进行15种四环素耐药基因的筛查,发现生猪肉加工厂设备食品接触面存在9种四环素耐药基因,包括tet L、tet A、tet B、tet C、tet E、tet M、tet S、tet K和tet X,其检出率分别为7.7%、6.0%、4.8%、4.8%、3.6%、3.6%、3.6%、1.2%和0.6%。本研究结果表明,生猪肉加工厂食品接触面四环素耐药菌污染严重,可能交叉污染生猪肉制品,其携带的四环素耐药基因可能向不同细菌种属间转移,进而由食物链向人类传播,对人类健康造成潜在的威胁。     

Microflora of minimally processed frozen vegetables sold in Gaborone, Botswana

Two hundred samples of minimally processed, frozen, and prepacked potato chips, peas, corn, and a variety of combined vegetables from supermarkets in Gaborone, Botswana, were examined microbiologically. Determination of aerobic mesophilic plate count, aerobic psychrotrophic plate count, lactic acid bacteria, yeasts and molds, coliforms, Listeria spp., and Staphylococcus aureus were done. Chips had the lowest mean log values for all of the microorganisms enumerated except yeasts and molds. The mean log values for single vegetables ranged from 3.6 to 9.1, 3.4 to 8.9, 2.9 to 5.6, and 2.1 to 6.5 log CFU/ g aerobic mesophilic plate count, aerobic psychrotrophic plate count, lactic acid bacteria, and yeasts and molds, respectively. The microbial profiles of peas and corn were almost similar (P < 0.001). The mean values for combined vegetables were clustered within 4.6 and 5.4 and 4.2 and 5.2 log CFU/g aerobic mesophilic plate count and aerobic psychrotrophic plate count, respectively. All of the vegetables had a coliform population distribution ranging from 0 to < 10(4) most probable number per g. The predominant gram-negative bacteria isolated included members of Enterobacteriaceae and Pseudomonaceae (86.2%). Escherichia coli was not detected in all of the samples. The organisms isolated included those responsible for spoilage in frozen vegetables, namely Pseudomonas, Klebsiella, Corynebacterium, lactic acid bacteria, and Flavobacterium. The predominant lactic acid bacteria were Lactobacillus spp. (55.9%). Other spoilage organisms were yeasts, and Cryptococcus spp. (55.4%) was predominant. Pathogens, namely Listeria monocytogenes, were also isolated at a rate of 2 to 10%, of which 4% was from corn, 2% each from peas and country crop, and 10% from stir-fry. Bacillus cereus was also isolated and accounted for 7.7% of the microorganisms from corn. S. aureus was isolated from all of the vegetables. Enterotoxigenic strains were from corn, peas, mixed vegetables, and stir-fry, and all of them produced enterotoxin A. In addition, the isolates from stir-fry vegetables also produced enterotoxins B and C. The study reveals the presence of pathogens and emerging opportunistic pathogens in the ready-to-use or ready-to-eat vegetables. If E. coli is the only indicator for safety and acceptability, consumers may be exposed to foodborne diseases. Inclusion of other groups as indicator organisms is suggested. Retailers are urged to invest in standby generators to maintain the cold chain.     

羊肉屠宰加工场主要污染菌的分布及其对熟制羊肉的致腐能力

对江苏省苏州市具有代表性的某羊屠宰场的屠宰环境及熟制品加工车间进行微生物检测,重点对熟制品加工过程进行检测,包括煮制车间的接触面、各加工车间的空气以及清洗前后的生肉与煮制后的熟肉,以确定熟制品加工过程中污染菌群的分布。结果表明,熟制品加工过程中各加工车间空气细菌数均低于10 CFU/皿,表明空气质量合格。而煮制车间的接触面污染较严重致使交叉污染造成熟制羊肉的菌落总数达到3.23(lg(CFU/cm~2))。结合形态观察和16S rDNA菌种鉴定,所污染的菌主要为芽孢杆菌、腐生葡萄球菌、变形杆菌、金黄杆菌和微杆菌等。随后选取3个污染菌芽孢杆菌(Bacillus sp.M1、Bacillus sp.M9)和腐生葡萄球菌(Staphylococcus saprophyticus M7),通过对熟制羊肉的感官评分、pH值、菌落总数、挥发性盐基氮值和腐败代谢产物产量因子的测定评定它们对熟制羊肉的致腐能力。结果显示,Bacillus sp.M1的致腐能力最强且明显高于S.saprophyticus M7和Bacillus sp.M9,为有效预防和控制熟制羊肉的微生物污染提供依据。     

冷海水保藏下鲐鱼(Pneumatophorus japonicus)菌相变化规律及优势腐败菌的分离鉴定

以冷海水保鲜的鲐鱼为研究对象,通过选择性培养基和16S r DNA序列分析法探究其在冷海水保鲜过程中的菌相变化,确定了鲐鱼在冷海水保鲜条件下的优势腐败菌,并通过MEGA5.2软件构建了贮藏末期代表菌株的系统发育树。结果表明:冷海水保鲜鲐鱼样品在贮藏初期(第0 d)的微生物比较复杂,优势种群是假单胞菌属(Pseudomonas sp.)和嗜冷菌属(Psychrobacter sp.),还有少量的类芽孢杆菌属(Paenibacillus sp.)、希瓦氏菌属(Shewanella sp.)、蜡状芽孢杆菌(Bacillus anthracis)、枯草芽孢杆菌属(Brevibacterium sp.);随着贮藏时间的延长,鲐鱼样品中的菌相逐渐变的单一,假单胞菌属迅速下降,希瓦氏菌属迅速增加;贮藏末期希瓦氏菌属和肠杆菌属(Enterobacter sp.)的比例迅速增加,其中希瓦氏菌属呈上升趋势且到贮藏后期数量占绝对优势,被确定为鲐鱼冷海水保鲜条件下的优势腐败菌。