An outbreak of ammonia poisoning from chicken tenders served in a school lunch

Although foodborne outbreaks of illness are relatively common, they are rarely caused by chemical agents. An outbreak of gastrointestinal illness occurred among students at two schools shortly after lunch was served. A cohort study, an environmental investigation, and microbiological and toxicological laboratory testing of food samples were performed. A case was defined as a student or teacher who ate food prepared in the kitchen at school A on 25 November 2002 (and served at schools A and B) and who later developed headache or symptoms of gastrointestinal tract irritation, with onset within 180 min of eating lunch. Among 312 persons interviewed, 157 persons became ill (attack rate = 49%; attack rate 41% for school A, 11% for school B). Onset of illness occurred within 60 min for 81% of cases; 91% of students reported that their chicken tenders smelled unusual. Eating chicken tenders that smelled unusual was associated with being a case (relative risk 9.2, 95% confidence interval 1.4 to 62.6, P < 0.05). Ammonia was detected in uncooked chicken tenders at levels as high as 2,468 ppm. The chicken had been contaminated during a warehouse leak of ammonia refrigerant. This outbreak of ammonia poisoning is only the second reported in food, and the first in a solid food. Heated chicken tenders contaminated with ammonia can cause acute illness within a short period of time.     

Concurrent outbreaks of Shigella sonnei and enterotoxigenic Escherichia coli infections associated with parsley: implications for surveillance and control of foodborne illness

In recent years, the globalization of the food supply and the development of extensive food distribution networks have increased the risk of foodborne disease outbreaks involving multiple states or countries. In particular, outbreaks associated with fresh produce have emerged as an important public health concern. During July and August 1998, eight restaurant-associated outbreaks of shigellosis caused by a common strain of Shigella sonnei occurred in the United States and Canada. The outbreak strain was characterized by unique pulsed-field gel electrophoresis patterns. Epidemiologic investigation determined that the illness was associated with the ingestion of parsley at four restaurants; at the other four restaurants, the majority of the people who contracted the illness ate parsley. Isolates from patrons in two unrelated restaurant-associated enterotoxigenic Escherichia coli (ETEC) outbreaks in Minnesota shared a common serotype and pulsed-field gel electrophoresis (PFGE) pattern. Parsley was the implicated or suspected source of both ETEC outbreaks. In each of the outbreak-associated restaurants, parsley was chopped, held at room temperature, and used as an ingredient or garnish for multiple dishes. Infected food workers at several restaurants may also have contributed to the propagation of the outbreak. The sources of parsley served in outbreak-associated restaurants were traced, and a 1,600-acre farm in Baja California, Mexico, was identified as a likely source of the parsley implicated in six of the seven Shigella outbreaks and as a possible source of the parsley implicated in the two ETEC outbreaks. Global food supplies and large distribution networks demand strengthened laboratory and epidemiologic capacity to enable state and local public health agencies to conduct foodborne disease surveillance and to promote effective responses to multistate outbreaks.     

Salmonella Thompson associated with improper handling of roast beef at a restaurant in Sioux Falls, South Dakota

In October 1996, we investigated an outbreak of Salmonella serotype Thompson infections associated with Restaurant A in Sioux Falls, South Dakota, and conducted two cohort studies among persons who ate at luncheons catered by Restaurant A. Fifty-two Salmonella Thompson infections were identified between 29 September and 14 October 1996. Infections occurred among employees and patrons at Restaurant A and among attendees at three luncheons catered by the restaurant on 7 October. Roast beef cooked at Restaurant A was the only food item significantly associated with illness. Cooking times and storage temperatures for roast beef were inadequate to prevent multiplication of Salmonella, and the chefs were unaware of proper cooking and storage temperatures. We conclude that improper handling of roast beef probably caused this outbreak of Salmonella Thompson infections. Better knowledge of food safety practices by the cooking staff at Restaurant A, through required food safety education, might have prevented the outbreak.     

乌鲁木齐铁路地区1974年～1996年食物中毒分析

为掌握乌鲁木齐铁路地区食物中毒的规律 ,对该地区 1974年～ 1996年的食物中毒情况进行了综合分析。 2 3年来 ,该地区共发生食物中毒 34起 ,中毒人数 115 6人 ,无死亡。食物中毒主要发生在集体食堂 ,13起 (38 3% ) ,70 4人 (6 0 9% )。高发季节为夏秋季 ,2 2起 (6 4 7% ) ,6 2 9人(5 4 4 % )。中毒食品以肉及肉制品为主 ,2 1起 (6 1 7% ) ,6 33人 (5 4 8% )。中毒原因主要为致病性微生物 ,2 9起 (85 3% ) ,987人 (85 4 % ) ,其中以沙门氏菌 (8起 ,175人 )和葡萄球菌属 (7起 ,119人 )引起的为多。分析结果提示 ,应加强铁路沿线的食品卫生管理 ,尤其注意职工集体食堂、肉及肉制品、微生物致病菌。     

Vibrio parahaemolyticus: a concern of seafood safety

Vibrio parahaemolyticus is a human pathogen that is widely distributed in the marine environments. This organism is frequently isolated from a variety of raw seafoods, particularly shellfish. Consumption of raw or undercooked seafood contaminated with V. parahaemolyticus may lead to development of acute gastroenteritis characterized by diarrhea, headache, vomiting, nausea, and abdominal cramps. This pathogen is a common cause of foodborne illnesses in many Asian countries, including China, Japan and Taiwan, and is recognized as the leading cause of human gastroenteritis associated with seafood consumption in the United States. This review gives an overview of V. parahaemolyticus food poisoning and provides information on recent development in methods for detecting V. parahaemolyticus and strategies for reducing risk of V. parahaemolyticus infections associated with seafood consumption.     

一起由金黄色葡萄球菌所致学校食物中毒调查分析

目的 查明一起学校食物中毒发生的原因和可疑危险因素,提出有效控制措施防止事态蔓延,为类似食源性疾病的调查和预防提供参考.方法 利用现场流行病学、食品卫生学和实验室检测等方法,开展病例主动搜索、个案调查和现场卫生学调查,采集食品、外环境和病例的标本进行实验室检测,以判断本次事件的可疑餐次和食物.结果 通过开展主动搜索,共...     

Report of illnesses caused by aldicarb-contaminated cucumbers

During May and June of 1985 the Health Protection Branch and several other agencies were involved in the investigation of over 300 reports of illness reported in the Vancouver area of British Columbia, Canada. Symptoms reported included nausea, vomiting, dizziness, muscle fasciculation and blurred vision. A review of the onset of symptoms and food consumed suggested that at least 140 people had become ill from eating cucumbers adulterated with a carbamate pesticide. The presence of residues of aldicarb in cucumbers from one particular producer was confirmed by laboratory analysis.     

同一肇事地不同餐次食物中毒现场流行病学调查及肠毒素基因鉴定

目的查明本次食物中毒发生的原因,确认致病危害因素及其来源,控制暴发的扩散和蔓延。方法采用现场流行病学调查方法,开展病例搜索和个案调查,并采集相关样本进行实验室检测及肠毒素基因鉴定。运用流行病学曲线推算潜伏期范围,确定中毒餐次和中毒食品。结果共搜索确诊中毒病例27例,主要临床特征为恶心、呕吐、腹泻,部分病例伴腹痛、头痛、头晕等。中毒餐次为2014年12月10日的午餐和晚餐,中毒食品为烤肉拌饭,致病因子为金黄色葡萄球菌A型肠毒素。烤肉中分离的金黄色葡萄球菌菌株间PFGE图谱相似度100%,具有同源性;RT-PCR鉴定毒素基因为A型肠毒素。结论发生在同一肇事地不同餐次由金黄色葡萄球菌A型肠毒素引起的食物中毒,交叉污染是金黄色葡萄球菌污染来源最重要的传播方式,应加强餐饮行业监管和关键环节控制,防止类似事件的再次发生。     

Complaints of foodborne illness in San Francisco, California, 1998

Foodborne diseases are an important public problem affecting millions of Americans each year and resulting in substantial morbidity and mortality. Many foodborne infections occur in outbreak settings. Outbreaks are often detected by complaints from the public to health authorities. This report reviews complaints received by the San Francisco Department of Public Health involving suspected foodborne illness in 1998. Although such foodborne complaints are commonly received by health officials, we provide the first review of population-based data describing such complaints. We use a broad definition of a foodborne disease outbreak. We judged a complaint to be a "likely foodborne disease outbreak" if it involved more than one person and more than one family; no other common meals were shared recently by ill persons; diarrhea, vomiting, or both was reported; and the incubation period was more than one hour. In 1998, 326 complaints of foodborne illness, involving a total of 599 ill people, were received by the Communicable Disease Control Unit in San Francisco. The complaints involved from 1 to 36 ill persons, with 61% involving one ill person and 25% involving two ill persons. Of the 126 reports involving illness in more than one person, 77 (61%) were judged to be likely foodborne disease outbreaks. Three of these 77 outbreaks had been investigated prior to our review. This project confirms that more foodborne disease outbreaks occur than are reported to state and national outbreak surveillance systems. Our review of the San Francisco system highlights opportunities for gleaning valuable information from the foodborne disease complaint systems in place in most jurisdictions.     

European Food Poisoning Outbreaks Involving Meat and Meat-based Products

Foodborne illnesses are syndromes including nausea, vomiting, abdominal cramps and diarrhea caused by the ingestion of food contaminated by chemical substances or microorganisms and/or their toxins. Reporting of food poisoning has been mandatory for European Union member states since 2003. Data collected by the European Food Safety Authority (EFSA) include number of outbreaks per causative agent, number of human cases as well as hospitalization and death rates. This paper will focus on meat products as food vehicles for FBOs. Following the legal definition of meat and meat products and the European reporting scheme, the main pathogenic bacteria will be presented.     

Beliefs about meals eaten outside the home as sources of gastrointestinal illness

In a 2002 telephone survey of 16,435 randomly selected U.S. residents, respondents answered several questions about their beliefs concerning sources of gastrointestinal illness. Of those who had experienced vomiting or diarrhea in the month before their telephone interview, 22% believed the source of their gastrointestinal illness was a meal eaten outside the home. I11 respondents who had diarrhea but not vomiting and who did not miss work because of their illness were more likely to believe the illness resulted from a specific outside meal. I11 respondents attributed their illness to a specific outside meal for several reasons, including symptom timing (43%) and illness of their meal companions (6%). Eight percent of ill respondents reported their illness to a health department or the restaurant suspected of causing the illness. Those with vomiting and those who missed work or activities because of their illness were more likely to report their illness. Most respondents (54%) who attributed their illness to a specific outside meal said their illness symptoms began within a short time (5 h) of eating that meal. The foodborne illnesses for which this is a likely time frame typically are associated with vomiting, but respondents with vomiting did not report a shorter symptom onset than respondents without vomiting. These findings suggest that ill respondents may have the misconception that foodborne illness symptoms typically occur shortly after ingestion of contaminated food. Results suggest that education efforts should focus on the nature and timing of foodborne illness symptoms and the importance of reporting suspected foodborne illnesses.     

Archiving of food samples from restaurants and caterers--quantitative profiling of outbreaks of foodborne salmonellosis in Japan

The Ministry of Health, Labor and Welfare (former MHW) of Japan issued a Directive in 1997 advising restaurants and caterers to freeze portions of both raw food and cooked dishes for at least 2 weeks. This system has been useful for determining vehicle foods at outbreaks. Enumeration of bacteria in samples of stored food provide data about pathogen concentrations in the implicated food. Data on Salmonella concentrations in vehicle foods associated with salmonellosis outbreaks were collected in Japan between 1989 and 1998. The 39 outbreaks that occurred during this period were categorized by the settings where the outbreaks took place, and epidemiological data from each outbreak were summarized. Characteristics of outbreak groups were analyzed and compared. The effect of new food-storage system on determination of bacterial concentration was evaluated. Freezing and nonfreezing conditions prior to microbial examination were compared in the dose-response relationship. Data from outbreaks in which implicated foods had been kept frozen suggested apparent correlation between the Salmonella dose ingested and the disease rate. Combined with results of epidemiological investigation, quantitative data from the ingested pathogen could provide complete dose-response data sets.     

浦东新区某学校一起沙门菌食物中毒事件调查

目的 对上海市浦东新区某学校发生的一起食物中毒事件进行流行病学调查分析,查明致病因子、致病食品及其污染来源,采取有效控制措施,为今后此类事件的调查处置提供参考。方法 采用描述流行病学方法分析本次事件病例的流行病学特征,开展病例对照研究分析可疑食品；食品卫生学调查采用访谈和现场勘查的方式,了解食品制作、运输、贮存过程及其原料来源；采集病例和从业人员肛拭子样本、食品及其加工环节样本、饮用水样进行实验室检测。结果 共调查发现疑似病例51例,临床表现以腹泻、发热、腹痛、头痛、恶心和呕吐为主。发病潜伏期为2.5～51 h,中位数20 h。病例对照分析表明2018年9月4日早餐中的三明治是可疑高危食物。7例病例的肛拭子样本检出沙门菌,分离的阳性菌株经脉冲场凝胶电泳(PFGE)分子分型分析表明均来自相同感染源,且存在多型别沙门菌同时感染的情况。结论 该事件是一起由沙门菌感染引起的食物中毒事件,可疑食物为三明治。建议学校供餐单位应加强供餐食品审核,严格执行留样制度,落实各项食品安全措施。     

Systematic environmental evaluations to identify food safety differences between outbreak and nonoutbreak restaurants

Restaurants are important settings for foodborne disease transmission. The Environmental Health Specialists Network (EHS-Net) was established to identify underlying factors contributing to disease outbreaks and to translate those findings into improved prevention efforts. From June 2002 through June 2003, EHS-Net conducted systematic environmental evaluations in 22 restaurants in which outbreaks had occurred and 347 restaurants in which outbreaks had not occurred. Norovirus was the most common foodborne disease agent identified, accounting for 42% of all confirmed foodborne outbreaks during the study period. Handling of food by an infected person or carrier (65%) and bare-hand contact with food (35%) were the most commonly identified contributing factors. Outbreak and nonoutbreak restaurants were similar with respect to many characteristics. The major difference was in the presence of a certified kitchen manager (CKM); 32% of outbreak restaurants had a CKM, but 71% of nonoutbreak restaurants had a CKM (odds ratio of 0.2; 95% confidence interval of 0.1 to 0.5). CKMs were associated with the absence of bare-hand contact with foods as a contributing factor, fewer norovirus outbreaks, and the absence of outbreaks associated with Clostridium perfringens. However, neither the presence of a CKM nor the presence of policies regarding employee health significantly affected the identification of an infected person or carrier as a contributing factor. These findings suggest a lack of effective monitoring of employee illness or a lack of commitment to enforcing policies regarding ill food workers. Food safety certification of kitchen managers appears to be an important outbreak prevention measure, and managing food worker illnesses should be emphasized during food safety training programs.     

一起嗜水气单胞菌引起的食物中毒调查

目的 了解本次食物中毒中毒原因及可疑食物污染来源.方法 采用病例对照研究方法,并采集可疑食物及病例标本进行检测.结果 共发生病例48例,症状主要为腹痛(100％)、腹泻(85％)、发热(40％)等.潜伏 期中位数为25 h,进食白切鸡是危险因素(OR=6.0,95％ CI:2.0～17),且与发病呈剂量反应关系((x2趋势=4.5,P=0.03).白切鸡及病例粪便中检出嗜水气单胞菌.结论 进食被嗜水气单胞菌污染的白切鸡是本次食物中毒发生的主要原因,建议加强农村游厨的食品卫生安全知识培训,防止类似事件发生.     

Source attribution of nontyphoid salmonellosis in new zealand using outbreak surveillance data

In this study, 204 New Zealand outbreaks of non-typhoid salmonellosis reported from 2000 to 2009 were analyzed for information on the sources of human infection. Data were extracted from the outbreak module of EpiSurv, New Zealand's notifiable diseases database, and augmented with information from individual case reports and separate investigation reports. The outbreaks involved 1,426 cases, representing an estimated 9% of the total salmonellosis cases reported for the study period. Salmonella Typhimurium was the causative serotype in 78% of 172 outbreaks for which a serotype was available, involving 71% of outbreak cases. The most commonly reported outbreak setting was the home (47% of outbreaks), followed by commercial food operations (31%). Foodborne transmission was reported for 63% of the 123 outbreaks for which only one mode of transmission was reported, followed by person-to-person transmission (32%), waterborne transmission (3%), and zoonotic transmission (2%). However, evidence for the mode of transmission was weak or absent for 107 (63%) of the 169 outbreaks for which a mode of transmission was reported. For only 22 outbreaks was laboratory evidence successfully used to identify a potential source of infection. Of these 22 outbreaks, 7 were foodborne, 11 involved an infected food handler, 2 were attributed to contact with animals, 1 was attributed to consumption of drinking water, and 1 was attributed to multiple sources. The laboratory-confirmed contaminated foods were diverse and included imported and domestically produced foods. The results of this analysis support the hypothesis that non-typhoid salmonellosis is primarily a foodborne disease in New Zealand, but there is insufficient evidence to confirm important food vehicles.     

Salmonella outbreaks in restaurants in Minnesota, 1995 through 2003: evaluation of the role of infected foodworkers

The 23 restaurant-associated salmonellosis outbreaks that occurred in Minnesota from 1995 through 2003 were reviewed to characterize the role of infected foodworkers. The median duration of the outbreaks was 21 days (range, 1 to 517 days). The median number of culture-confirmed patron cases per outbreak was seven (range, 1 to 36 cases). The median incubation for patron cases ranged from 9 h to 5.9 days. A specific food vehicle was implicated in four outbreaks and suspected in five. Salmonella of the same serotype and pulsed-field gel electrophoresis subtype as that found in patrons was recovered from foodworkers in 19 outbreaks. Overall, 12% (129 of 1,033) of foodworkers tested positive for Salmonella. Sixty-four (53%) of 121 Salmonella-positive foodworkers reported not having had a recent gastrointestinal illness. Overall, the median duration of Salmonella shedding was 16 days. Among foodworkers who reported gastrointestinal illness, the median shedding duration was 30 days as compared with 3 days for asymptomatic foodworkers. Positive environmental samples were recovered in 4 (33%) of 12 outbreaks. No specific food vehicle was identified in any outbreaks associated with Salmonella-positive environmental samples. The median duration of outbreaks with positive environmental samples (187 days) was significantly longer than the median duration of outbreaks with negative environmental results (26 days, P = 0.03). A higher proportion of Salmonella-positive foodworkers (22 versus 8%) was identified in outbreaks with positive environmental samples. Salmonella outbreaks in restaurants are frequently prolonged yet produce a small number of confirmed patron cases. Prolonged outbreak durations suggest a persistent reservoir of contamination. Infected foodworkers likely serve as an important source for Salmonella transmission. Therefore, assessment of foodworker infection is essential for controlling restaurant outbreaks.     

一起副溶血性弧菌致食源性疾病暴发疫情的流行病学调查

目的查明S饭店群体性食源性疾病暴发的原因,找出可疑食物,防止类似事件再次发生。方法制定病例定义,开展病例搜索,对病例信息进行描述性分析和病例对照研究,并采集病例粪便标本、剩余食物样品等进行实验室检测。结果暴发病例162例,罹患率22.2%(162/730),临床表现主要为腹泻(100%,162/162)、腹痛(96.3%,156/162)、乏力(77.2%,125/162)、恶心(68.5%,111/162)、呕吐(53.1%,86/162),平均潜伏期为12 h,病例对照结果显示扇贝(OR=1.74,95%CI=1.00~3.02)和牛仔骨(OR=2.87,95%CI=1.38~5.99)为可疑危险因素,34份粪便标本、1份甲鱼切块和1份砧板上检出副溶血性弧菌。结论本次事件为一起副溶血性弧菌污染宴席食物导致群体性食源性疾病暴发事件,交叉污染和食品未加工熟透很可能是发病的主要原因,建议餐饮机构要规范操作流程,加强自我监管,防止此类事件再次发生。     

An outbreak of food poisoning due to egg yolk reaction-negative Staphylococcus aureus

An outbreak of staphylococcal food poisoning due to an egg yolk (EY) reaction-negative strain occurred in Japan. Twenty-one of 53 dam construction workers who ate boxed lunches prepared at their company cafeteria became ill, and eight required hospital treatment. The outbreak showed a typical incubation time (1.5-4 h with a median time of 2.7 h) and symptoms (vomiting and diarrhea) of staphylococcal food poisoning. Staphylococcus aureus, which produces staphylococcal enterotoxin (SE) A, was isolated from four fecal specimens of eight patients tested. Scrambled egg in the boxed lunches contained 20-40 ng/g of SEA, and 3.0 x 10(9)/g of viable S. aureus cells that produced this toxin. All isolates from patients and the food were EY reaction-negative, coagulase type II, and showed the same restriction fragment length polymorphism (RFLP) pattern. We concluded that the outbreak was caused by scrambled egg contaminated with EY reaction-negative S. aureus. In Japan, outbreaks of staphylococcal food poisoning are mainly caused by EY reaction-positive S. aureus, and EY reaction-negative colonies grown on agar plates containing EY are usually not analyzed further for detection of S. aureus. The present outbreak suggested that EY reaction-negative isolates should be subjected to further analysis to detect the causative agents of staphylococcal food poisoning.     

一起误食野蘑菇中毒事件的调查分析

目的 调查分析一起野蘑菇中毒事件,为毒蘑菇中毒的防控提供参考。方法 通过流行病学调查、食品卫生学调查、实验室检测、动物试验,查找本次食物中毒原因。结果 搜索发现同一家庭中毒患者4名,罹患率80.0%,临床表现为恶心、呕吐、腹痛、腹泻等胃肠道症状,平均潜伏期3h,食用野蘑菇与发病之间存在剂量-反应关系。采集剩余野蘑菇7个及患者指认的草坪现场同一种类野蘑菇4个,经形态学鉴定为大青褶伞,动物试验显示该野蘑菇有消化系统毒性。结论 本次中毒事件为一起误食有毒大青褶伞引起的食物中毒事件。