Prevalence of foodborne pathogens in retailed foods in Thailand

Abstract The consumption of foodborne pathogens contaminated in food is one of the major causes of diarrheal diseases in Thailand. The objective of this study was to evaluate the prevalence and types of contaminating bacteria in retailed foodstuffs in Thailand. Food from four categories (137 samples total), including meat (51 samples), vegetables (38 samples), fish or seafood (37 samples), and fermented food (11 samples), was purchased randomly from seven different open-markets and seven supermarkets in Thailand from August 2010 to March 2011. Seven types of major foodborne pathogens were identified using conventional culture methods. Approximately 80% of meat samples tested was contaminated with Salmonella spp. In contrast, the Salmonella spp. contamination rate of vegetable (5%) or fermented food (9%) samples was comparatively low. Six strains of Cronobacter sakazakii and two strains of Yersinia enterocolitica were also isolated. A substantially higher rate of contamination by Bacillus cereus was observed in fermented food (82%) than in samples of meat (2%) and fish or seafood (5%). Seven Listeria spp. isolates were obtained from meat and fish or seafood samples. Approximately 39% of samples tested were found to be contaminated with Staphylococcus spp. (54 isolates). The rate of bacterial contamination of meat did not depend on the type of market. However, the contamination rate of Staphylococcus spp. in vegetables was higher in open markets than in supermarkets, and the contamination rate of Salmonella spp. and Staphylococcus spp. in fish or seafood samples purchased in open markets was likewise higher than in those purchased in supermarkets. Therefore, improvement of hygienic practices throughout the food chain may be required to reduce the risk of food poisoning.     

常见食源性致病菌基因芯片鉴定技术

目的：建立鉴定食源性致病菌的基因芯片技术。方法：采用复合PCR方法扩增致病菌特异性DNA片段，结合基因芯片杂交技术鉴定不同的食源性致病菌。结果：本研究完成了采用3对引物的复合PCR扩增；不同致病菌特异性核苷酸片段同时布阵在一张芯片上；标记物质采用了非放射性的生物素，经不同标准菌种、实际检验样品和水平测试样品的考核验证，该鉴定系统灵敏度达620cfu／g，特异性高，基因芯片质量稳定，该鉴定系统基本含盖了目前食源性致病菌鉴定的需要。结论：常见食源性致病菌基因芯片鉴定技术，可为常规细菌检验方法的最终鉴定提供进一步佐证，尤其在一些培养条件苛刻的致病菌（产单核李斯特菌、弯曲菌等）的鉴定，以及在VITEK仪无法鉴定和手工鉴定判断误差大的情况下，基因芯片方法将发挥其独特的技术性优势，大大提高检验鉴定结果的准确性。     

Composition of ready cooked foods sampled in southern Thailand

This study investigated the nutrient composition of ready cooked foods commonly consumed in southern Thailand. Four samples of fourteen types; eight curry dishes, one sweet and sour curry, a soup dish, one stir-fried curry, one stir-fried dish and two single plate dishes were each purchased from 4 different shops around Hat Yai district. The edible part was blended and analysed for its nutrients content per 100 g edible portion. Cassia curry, Thai noodle salad, Ark shell curry and Fermented fish gut dish were a good source of vitamin B1 (145 microg), vitamin C (2.20 mg), calcium (0.23 g) and iron (6.07 mg), respectively. Moisture, ash, fat, protein and carbohydrate were high in Mungbean noodle soup (92.6 g), Fermented fish gut dish (4.1 g), Cassia curry (9.9 g), Stingray stir-fried curry (16.7 g) and Thai noodle salad (24.2 g). Results also showed that the main ingredients and cooking process determined the nutritional values of the foods. A new set of 4 samples of Round noodle in southern curry was purchased, each separated into its edible components and nutrient values estimated using the Thai single ingredient databases. Their nutrient content was also calculated using the data of similar food obtained from this study. Considerable differences amongst the values from the 2 sets of calculation were observed. Problems inherent in using the single ingredient databases were highlighted. This work demonstrates a need to create a food composition database of whole cooked meals ready for serving that reflects real life consumption.     

中国南方某市几种市售食品中多溴联苯醚污染状况研究

目的:检测分析中国南方某城市几种市售食品中多溴联苯醚污染水平。方法:采集市售7种食品,通过索氏抽提,酸性硅胶处理,利用硅胶柱和铝柱净化,用高分辨气相色谱/高分辨质谱检测分析,检测的多溴联苯醚单体包括三溴代到七溴代的PBDEs。结果:PBDE化合物在分析的食品中污染水平平均值的顺序为蛋类(227.15 pg/g)>鱼类(189.50 pg/g)>猪肉(75.40 pg/g)>牛肉(51.03 pg/g)>猪内脏(13.33 pg/g)>大米类(7.67 pg/g)>蔬菜类(2.39 pg/g)。在所有样品中单体BDEs 47在PBDE总量中占有最大分量,所占的比重在不同食品中约为12%~65%。结论:人类暴露主要是通过摄食受污染的食品,食品中PBDE的污染应引起重视。     

Survival and growth of foodborne microorganisms in processed and individually wrapped cheese slices

The objectives of the research reported here were to determine the growth, survival, or inactivation of selected microorganisms on individually wrapped processed cheese (IWC) slices stored at 5 degrees C and 22 degrees C, and to compare quality indices. IWC slices were spot-inoculated with foodborne pathogenic bacteria (Listeria monocytogenes, Staphylococcus aureus, and Salmonella spp.), spoilage bacteria (Pseudomonas spp. and Lactobacillus spp.), and spoilage molds (Penicillium spp. and Cladosporium spp.). Each bacterium was inoculated at 10(5) CFUs/g for determination of growth, survival, or inactivation. Molds were inoculated at 10(2) spores per gram and observed for growth. Fifty percent of the inoculated product samples were held at 5 degrees C (to simulate refrigeration), and the other 50 percent were held at 22 degrees C (to simulate ambient temperature) throughout shelf life. Samples taken on days 0, 3, 7,10, 14, and 28 and after 2, 3, 6, and 9 months, and were evaluated for surviving cells (by means of appropriate selective media), color (with the cheese color guide), and lipid oxidation (by means of peroxide values). Bacterial inactivation was observed in all conditions. At 14 days, a 5-log reduction was observed for Listeria monocytogenes and Salmonella, while a 3-log reduction was observed for Staphylococcus aureus. For Pseudomonas spp. and Lactobacillus spp., a 2-log reduction was observed within 3 days, with an additional 1-log reduction noted after several months. Mold levels showed no change during the first several weeks of storage. At 84 days, mold levels decreased at 5 degrees C, but they showed growth at 22 degrees C, to approximately 10(5) CFUs/g. Visual color was evaluated on a 10-point National Cheese Institute scale. During storage at 5 degrees C or 22 degrees C, color became darker and values increased from 4 to 5 and 4 to 7, respectively. Higher peroxide values were also obtained for the samples held at 22 degrees C versus 5 degrees C. From a microbiological standpoint, pathogenic and spoilage bacteria were unable to grow in this product; however, long-term storage at 22 degrees C led to lower product quality and mold growth.     

2012-2013年惠州市食品中食源性致病菌监测分析

目的了解惠州市食品中食源性致病菌的污染状况,为制订本市的食源性疾病预防策略提供依据。方法按照《广东省食品安全风险监测工作手册》要求,选择覆盖面广,有代表性的消费场所和重点监管的场所进行采样,按照《食源性致病菌监测工作手册》对样品进行检测。结果 2012-2013年共采集到457份样品,检出金黄色葡萄球菌、铜绿假单胞菌、阪崎肠杆菌、单增李斯特菌共11株食源性致病菌,致病菌的总检出率为2.41%,检出率最高的三种食品是凉拌食品6.25%,焙烤面包5.00%,烧烤肉2.86%。结论惠州市监测的食品中食源性致病菌检出率较低;凉拌食品、夹馅焙烤面包是主要的受污染品种,其中污染凉拌食品主要是李斯特菌,污染焙烤面包主要是金黄色葡萄球菌,需要有针对地加强监管。     

大连市2012-2013年食源性致病菌监测结果分析

目的了解大连市食品中食源性致病菌污染状况,为食源性疾病监测提供科学依据。方法依据《全国食源性致病菌监测工作手册》对食源性致病菌进行监测。结果 2012-2013年间共监测945份食品,总检出率为4.97%。检出副溶血性弧菌、致泻大肠埃希菌、蜡样芽胞杆菌、金黄色葡萄球菌、阪崎肠杆菌、单核细胞增生李斯特菌、沙门菌。水产品污染较严重,以副溶血性弧菌检出率最高,为7.14%。结论食品存在食源性致病菌污染较严重,应加强食源性致病菌的监测,防止食源性疾病和食物中毒发生。     

Prevalence and antibiotic resistance of foodborne Staphylococcus aureus isolates in Turkey

Abstract In this study, 154 Staphylococcus aureus isolates were detected from 1070 food samples (14.4%) collected from seven cities in Turkey. Antimicrobial susceptibility testing against 21 antibiotics was performed by agar disk diffusion method, and those isolates resistant to any antibiotic were further analyzed to determine minimum inhibitory concentration by E-test and polymerase chain reaction analysis of vanA and mecA genes. According to disk diffusion test results, a total of 139 strains were resistant to at least one tested antibiotic, with 39 (25.3%) strains being multidrug resistant (MDR) and the other 15 strains being susceptible to all antibiotics. Penicillin G, linezolid, erythromycin, and tetracycline took up 71.4%, 23.4%, 18.2%, and 15.6% of the tested strains, respectively. In addition, all of the strains were susceptible to vancomycin, oxacillin, cefoxitin, and imipenem. Only one strain (S158B) was resistant to both teicoplanin and cefazolin. On the other hand, the presence of vanA and mecA genes was not detected in the strains. Pulsed-field gel electrophoresis analysis was used to identify genetic-relatedness of the MDR strains. It is noteworthy that some strains from different sources showed 100% homology; however, some of MDR strains were found unrelated with 60% or less homology. The high diversity observed in pulsed-field gel electrophoresis results indicated the possible contamination of S. aureus from different sources and routes.     

Antimicrobial resistance and genetic relatedness among Salmonella from retail foods of animal origin: NARMS retail meat surveillance

Salmonella isolates were recovered from a monthly sampling of chicken breasts, ground turkey, ground beef, and pork chops purchased from selected grocery stores in six participating FoodNet sites (Connecticut, Georgia, Maryland, Minnesota, Oregon, and Tennessee) in 2002 and an additional two sites in 2003 (California and New York). In 2002 and 2003, a total of 6,046 retail meats were examined, including 1,513 chicken breasts, 1,499 ground turkey samples, 1,522 ground beef samples, and 1,502 pork chops. Retail meat samples tested increased to 3,533 in 2003 as compared to 2,513 in 2002. Overall, six percent of 6,046 retail meat samples (n = 365) were contaminated with Salmonella, the bulk recovered from either ground turkey (52%) or chicken breast (39%). Salmonella isolates were serotyped and susceptibility tested using a panel of 16 antimicrobial agents. S. Heidelberg was the predominant serotype identified (23%), followed by S. Saintpaul (12%), S. Typhimurium (11%), and S. Kentucky (10%). Overall, resistance was most often observed to tetracycline (40%), streptomycin (37%), ampicillin (26%), and sulfamethoxazole (25%). Twelve percent of isolates were resistant to cefoxitin and ceftiofur, though only one isolate was resistant to ceftriaxone. All isolates were susceptible to amikacin and ciprofloxacin; however, 3% of isolates were resistant to nalidixic acid and were almost exclusive to ground turkey samples (n = 11/12). All Salmonella isolates were analyzed for genetic relatedness using pulsed-field gel electrophoresis (PFGE) patterns generated by digestion with Xba1 or Xba1 plus Bln1. PFGE fingerprinting profiles showed that Salmonella, in general, were genetically diverse with a total of 175 Xba1 PFGE profiles generated from the 365 isolates. PFGE profiles showed good correlation with serotypes and in some instances, antimicrobial resistance profiles. Results demonstrated a varied spectrum of antimicrobial resistance and PFGE patterns, including several multidrug resistant clonal groups among Salmonella isolates, and signify the importance of sustained surveillance of foodborne pathogens in retail meats.     

Prevalence of associated microorganisms in genital discharge,Argentina

OBJECTIVE: There was a significant increase in the number of women demanding gynecological care in public hospital of the Great Buenos Aires, Argentina, between 1997 and 1998. It was necessary to update the prevalence of associated microorganisms in order to review the laboratory support and adjust prevention and control guidelines. METHODS: Samples from vaginal and endocervical discharge, from total cases: 84 adolescents (15 to 19 years) and 784 adults (20-60 years) attended in 1997-1998, were studied. Neisseria gonorrhoeae, Streptococcus agalactiae, Trichomonas vaginalis, Candida spp, and bacterial vaginosis, were diagnosed applying direct detection methods and specific culture isolation. Chlamydia trachomatis (antigen detection), Ureaplasma urealyticum and Mycoplasma hominis (culture) were also studied in part of the population. RESULTS: Patient care increased steadily from 1997 and there was an increase of 2.1 times from the first semester to the last one in 1998. Bacterial vaginosis was the most prevalent disease in the adult group, with 23.8%; followed by Candida spp 17.8%; S. agalactiae 5.6%; T.vaginalis 2.4%. In 50.3% of total adult cases neither bacterial vaginosis or presence of any sought microorganisms, was detected. In the adolescents group the most frequent detection was Candida spp with a 29.7%; bacterial vaginosis in 17.8%; followed by S. agalactiae 3.6%, T.vaginalis 2.4%. Also in this group on an important number of cases, 46.4%, none bacterial vaginosis or the presence of the sought microorganism were found. In some of the adult group, C. trachomatis (7/400) 1.76%, U. urealyticum (209/340) 61.4% and M. hominis (45/272) 16.5% were detected. CONCLUSIONS: Bacterial vaginosis and Candida spp prevalence is important in both groups. The absence of N. gonorrhoeae and lower prevalence of T. vaginalis and C. trachomatis is remarkable. A high prevalence of U. urealyticum and M. hominis were also detected, but the actual pathogenic role in adult women is still under discussion. The significant increase of attendance in the public system is due to social changes in the population and not due to changes in any particular pathology. Laboratory support has to be adjusted to the most cost-effective procedures to solve the most prevalent problems.     

2010-2012年合肥市食品中食源性致病菌监测结果分析

目的 通过分析安徽省合肥市食品中食源性致病菌监测工作的情况,为食品安全风险预警及监督管理提供科学依据.方法 按照《全国食源性致病菌监测工作手册》对合肥市2010-2012年食源性致病菌监测资料进行统计分析.结果 2010-2012年共检测食品样品753份,检出致病菌133株,总检出率17.66％;样品中霉菌和金黄色葡萄球菌检出率较高,分别为6.11％和5.71％;菌落总数与大肠菌群超标率分别为40.00％和38.62％,其中桶装饮用水菌落总数超标率最高,达到为65.15％.结论 合肥市居民食品中存在食源性致病菌污染,其中非发酵豆制品、桶装饮用水、熟制面米制品、水产品是主要污染食品品种,监测食品的菌落总数和大肠菌群超标问题突出,应加强针对性监管力度.     

Antimicrobial resistance among gram-negative foodborne bacterial pathogens associated with foods of animal origin

Antimicrobial-resistant foodborne pathogens are acquired primarily through consumption of contaminated food of animal origin or water. While there is much disagreement on the health burden imposed by resistance in foodborne bacterial pathogens, it is generally agreed that the use of antimicrobials, whether for growth promotion, prevention, or treatment, can select for resistant bacterial pathogens, and that these pathogens can be transmitted on food originating from sites processing treated animals. Information on the evolution and dissemination of antimicrobial resistance in foodborne pathogens shows that the situation is complex and differs by organism and antimicrobial. A clearer understanding of the ecology of resistance is needed in order to support science-based assessments of the public health risks due to the use of antimicrobials in the animal husbandry environment.     

2010—2012年酒泉市食品中食源性致病菌的监测分析

目的了解酒泉市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[5-6]。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,通过对2010—2012年度酒泉市采集食品样品共1157份的检验分析,对沙门氏菌、单核细胞增生李斯特菌、副溶血性弧菌、金黄色葡萄球菌、阪崎肠杆菌、志贺氏菌、大肠埃希菌O157∶H7对本市食品的污染情况进行监测。结果 1157份样品中,共检出致病菌100株,总检出率为8.64%。致病菌检出率分别为生畜肉16.67%(5/30)、生禽肉33.33%(10/30)、鲜冻水产品17.50%(7/40)、速冻熟制米面制品20.00%(8/40)、熟肉制品6.92%(9/130)、即食非发酵性豆制品14.5%(9/62)、婴幼儿配方食品3.81%(4/105)、冰激凌5.0%(1/20)、凉拌菜10.00%(18/180)、即食地方特色食品6.92%(9/130)、糕点及饼干1.25%(1/80)、熟制米面制品1.00%(1/100)、生奶22.50%(18/80)。即食蛋制品、生食果蔬菜、鲜榨果蔬汁中未检出致病菌。结论生肉、生奶和水产品是酒泉市食品的主要污染品种,作为直接入口食品的即食非发酵豆制品、凉拌菜、地方小吃、熟肉制品,可能导致较高的食源性疾病风险。     

深圳市市售食品中二恶英、多氯联苯污染现状研究

目的了解深圳市市售食品中二恶英、多氯联苯本底水平和污染情况,为开展食品中二恶英类化合物污染状况的风险评估和预警监测提供科学依据。方法于2004年10月至2008年10月期间,采集深圳市市售鱼、猪肉、牛肉、羊肉、鸡肉、鸭肉、禽蛋、奶粉、植物油、豆制品、米面、蔬菜12种食品共123份样品,参照美国国家环保局EPA1613、1668A方法,采用索式抽提装置和FMS自动纯化系统分别对样品进行提取和净化,采用同位素稀释技术,用已建立的高分辨气相色谱/高分辨双聚焦磁式质谱联用(HRGC/HRMS)超痕量有机分析技术平台,对样品中的7个多氯二苯并-对-二恶英(PCDD s)、10个多氯二苯并-对-呋喃(PCDFs)、4个共平面的多氯联苯(PCBs)化合物、8个单邻位取代的PCBs化合物以及6个指示性的PCBs化合物共计35个单体进行定量分析检测和毒性当量浓度汇总分析和评价。结果共检测123份市售食品样品,总二恶英(包括PCDD/Fs和PCBs)污染毒性当量浓度水平,动物性食品由大至小依次是:鱼类>禽蛋>牛肉>奶粉>羊肉>鸡肉>鸭肉>猪肉,植物性食品以植物油>豆制品>粮谷类>蔬菜依次降低。其中动物性食品以鱼类二恶英含量最高,...     

甘肃省社区人群食源性疾病患病因素分析

目的 了解甘肃省社区人群食源性疾病患病流行情况,并探索其影响因素,为制定疾病干预措施和合理配置卫生资源提供科学依据.方法 采用分层随机抽样方法于2011年12月-2013年11月选取甘肃省3个调查点共4917户居民,完成4229份样本人群的调查,通过人户面对面访谈的形式,用调查问卷收集信息.结果 食源性疾病加权月患病率...     

Prevalence and antimicrobial resistance of foodborne pathogens isolated from food products in China

This study was undertaken to investigate the prevalence of Salmonella, Listeria monocytogenes, Staphylococcus aureus, Vibrio parahaemolyticus, and Escherichia coli O157:H7 in Chinese food products. The prevalence of these pathogens was 3.46%, 5.79%, 7%, 0.24%, and 0%, respectively. Raw meats were mainly contaminated with Salmonella (39/365, 10.7%), L. monocytogenes (26/365, 7.1%), and S. aureus (40/365, 11%), while cooked food products were mainly contaminated with L. monocytogenes (45/384, 11.7%) followed by S. aureus (12/384, 3.1%), and raw milk was mainly contaminated with S. aureus (34/209, 16.3%) and Salmonella (4/209, 1.9%). Antimicrobial resistance was evaluated in Salmonella, L. monocytogenes, and S. aureus. Antimicrobial resistance for L. monocytogenes was most frequently observed for cefotaxime (51/72, 70.8%) followed by furazolidone (40/72, 55.6%). Multiple resistance (resistance to >or=2 antibiotics) was observed for 63.9% (46/72) of L. monocytogenes isolates. Resistance of Salmonella was most frequently observed to amoxicillin (11.6%), ticarcilline (11.6%), cephalothin (11.6%), and cefuroxime (11.6%). Multiple resistance was observed for 16.3% (7/43) of the Salmonella isolates. Staphylococcus aureus was resistant to penicillin (93.1%) followed by tetracycline and oxacillin COAG (49.4% and 37.9%, respectively). About 79% (69/87) of S. aureus isolated demonstrated multiple resistance. The data showed that raw meat, cooked food products, and raw milk were most commonly contaminated with foodborne pathogens and many pathogens were resistant to different antibiotics. The study provided useful information for assessment of the possible risk posed to Chinese consumers, which has significant public health impact in China.     

A foodborne outbreak of Salmonella infection due to overproduction of egg-containing foods for a festival

A large outbreak of gastroenteritis occurred in Catalonia in June 2002 with 1435 cases and 117 hospitalizations. Consumption of a hard pastry with vanilla cream was strongly associated with illness. Stool samples from cases and food-handlers were analysed. The premises of the food manufacturer were inspected and food samples were taken for microbiological analysis. Salmonella serotype Enteriditis was isolated from 154 cases, three food-handlers and nine food samples. Outbreak-associated strains showed a coincident phage type, antibiotype and pulse-field gel electrophoresis pattern. Inadequate handling of foods containing eggs occurred because the establishment exceeded its safe food production capacity to meet demand for the pastry, which was consumed on the day of a traditional festival. Excessive production of foods for holidays or special events represents a potential public health threat.     

Intake of sweet foods and counts of cariogenic microorganisms in obese and normal-weight women

OBJECTIVE: To study the intake of sweet foods in obese and normal-weight women, while also taking menstrual cycle effects on eating behaviour into consideration. An objective test of the intake of sugar-containing foods was introduced by measuring salivary counts of mutans streptococci and lactobacilli. DESIGN: A cross-sectional comparison of the intake of sweet foods in obese and normal-weight women. The obese women were also studied longitudinally after 10 weeks in a weight reduction programme. SUBJECTS: Obese (n=72, body mass index (BMI) 42.0+/-5.2 kg/m2) and normal-weight women (n=67, BMI 22.2+/-1.6 kg/m2) participated. RESULTS: Mutans streptococci in saliva were higher in obese than in normal-weight women (P<0.0001), although the reported habitual daily intake of sweet foods did not differ. Of the menstruating women, 80% of the obese subjects and 62% of the normal-weight ones (P<0.05) reported periods during the menstrual cycle with an 'extra large' intake of sweet foods; these intakes were higher in obese than in normal-weight women (P<0.01). The obese women reduced their intake of sweet foods after 10 weeks of weight reduction, although these changes were not pronounced enough to significantly affect the counts of cariogenic microorganisms. CONCLUSIONS: In contrast to most previous cross-sectional studies, this study shows that obese women have a higher intake of sweet foods, especially pre-menstrually. This was indicated by higher salivary counts of cariogenic microorganisms. SPONSORSHIP: Karolinska Institute Research Funds.     

Prevalence of VDRL Seroreactive in Myanmar Migrators in a Rural Area of Thailand

Although the prevalence of VDRL seroreactive in the Thai population has decreased in the recent years, migration of Myanmar laborers as carriers into Thailand may increase the prevalence of VDRL seroreactive. Screening is one of the recommended screening tests for the Myanmar migrators. In interest, epidemiology of VDRL seroreactive in Myanmar migrators has not been precisely determined. In this study, we reported the prevalence of VDRL seroreactive in Myanmar migrators in a rural community in the southern region of Thailand with high density of Myanmar migrators as fishermen. We analyzed the data of screening for VDRL seroreactive among 250 Myanmar migrators (169 males and 81 females) who have just stayed in Thailand for less than 1 month. The VDRL seroreactive rate among these Myanmar migrants was 3.2. The rates in males and females were 4.1% and 1.2%, respectively. Since these migrants can carry the disease to Thailand, screening test as one of the prevention strategies is necessary.