An outbreak of food-borne illness associated with methomyl-contaminated salt

Use of an ingredient-based analysis to investigate a national outbreak of Escherichia coli O157, United Kingdom, July 2016

Public Health England was alerted to a national outbreak of Shiga toxin-producing Escherichia coli O157 PT34 in July 2016. Early investigations suggested that the likely source was a salad item consumed outside of the home. A number of cases reported consuming meals at a staff canteen (Venue A) and a garden café (Venue B). Both venues shared a common salad supplier. An investigation was undertaken to measure associations between salad items and illness using an 'ingredient-based analysis'. A retrospective case-control study was conducted using an online questionnaire to collect information on menu items consumed at each venue. Chefs at both venues were interviewed to identify ingredients contained within each menu item. Both venues were pooled together for multivariable analysis measuring associations at the ingredient level. Among 203 responses, 24 cases were identified (13 confirmed, two probable and nine possible). Case onsets ranged between 7 and 25 June 2016. Multivariable analysis identified strong evidence that only baby mixed-leaf salad from the common supplier was a vehicle of infection (adjusted odds ratio = 13.1; 95% confidence interval: 1.6-106.5). Identifying the specific salad ingredient associated with illness was made possible by using an ingredient-based analysis. We recommend the increased use of ingredient-based analyses.

An outbreak of food borne illness due to methomyl pesticide intoxication in Korea

On February 21, 2013, 6 elderly people collapsed abruptly after eating bean sprout bibimbab (boiled rice mixed with bean sprouts and seasoned with soybean sauce) at a countryside restaurant in the Chungbuk Province, Korea. Minutes after eating the meal, all of the patients lapsed into a state of stupor. Respiratory arrest developed in 2 patients; and one of two patients died of cardiac arrest. The autopsy identified methomyl and methanol in the deceased patient's gastric contents and in the remaining soybeanbean sauce seasoning. Five of the 6 patients ingested one spoonful of the soybeanbean sauce seasoning and survived, while one patient who died of cardiac arrest, ingested approximately two spoons. Symptoms of toxicity presented quickly in the subjects and progressed rapidly, including chest tightness, an unusual sensation in the pit of the stomach, dizziness, ataxia, and finally, collapse. Three patients who drank ethanol with the meal experienced only mild toxic symptoms. Our analysis of the clinical observations in these cases suggests that ingestion of methomyl pesticide and the additive toxicity of methanol may have been responsible for the intoxication.

Investigation of outbreaks complicated by universal exposure

Outbreaks in which most or all persons were exposed to the same suspected source of infection, so-called universal exposure, are common. They represent a challenge for public health specialists because conducting analytical studies in such investigations is complicated by the absence of a nonexposed group. We describe different strategies that can support investigations of outbreaks with universal exposure. The value of descriptive epidemiology, extensive environmental investigation, and the hypothesis-generation phase cannot be overemphasized. An exposure that seems universal may in fact not be universal when additional aspects of the exposure are taken into account. Each exposure has unique characteristics that may not be captured when investigators rely on the tools readily at hand, such as standard questionnaires. We therefore encourage field epidemiologists to be creative and consider the use of alternative data sources or original techniques in their investigations of outbreaks with universal exposure.

German outbreak of Escherichia coli O104:H4 associated with sprouts

BACKGROUND

A large outbreak of the hemolytic-uremic syndrome caused by Shiga-toxin-producing Escherichia coli O104:H4 occurred in Germany in May 2011. The source of infection was undetermined.

METHODS

We conducted a matched case-control study and a recipe-based restaurant cohort study, along with environmental, trace-back, and trace-forward investigations, to determine the source of infection.

RESULTS

The case-control study included 26 case subjects with the hemolytic-uremic syndrome and 81 control subjects. The outbreak of illness was associated with sprout consumption in univariable analysis (matched odds ratio, 5.8; 95% confidence interval [CI], 1.2 to 29) and with sprout and cucumber consumption in multivariable analysis. Among case subjects, 25% reported having eaten sprouts, and 88% reported having eaten cucumbers. The recipe-based study among 10 groups of visitors to restaurant K included 152 persons, among whom bloody diarrhea or diarrhea confirmed to be associated with Shiga-toxin-producing E. coli developed in 31 (20%). Visitors who were served sprouts were significantly more likely to become ill (relative risk, 14.2; 95% CI, 2.6 to ∞). Sprout consumption explained 100% of cases. Trace-back investigation of sprouts from the distributor that supplied restaurant K led to producer A. All 41 case clusters with known trading connections could be explained by producer A. The outbreak strain could not be identified on seeds from the implicated lot.

CONCLUSIONS

Our investigations identified sprouts as the most likely outbreak vehicle, underlining the need to take into account food items that may be overlooked during subjects' recall of consumption.

Chemical-biological terrorism and its impact on children

Children remain potential victims of chemical or biological terrorism. In recent years, children have even been specific targets of terrorist acts. Consequently, it is necessary to address the needs that children would face after a terrorist incident. A broad range of public health initiatives have occurred since September 11, 2001. Although the needs of children have been addressed in many of them, in many cases, these initiatives have been inadequate in ensuring the protection of children. In addition, public health and health care system preparedness for terrorism has been broadened to the so-called all-hazards approach, in which response plans for terrorism are blended with plans for a public health or health care system response to unintentional disasters (eg, natural events such as earthquakes or pandemic flu or manmade catastrophes such as a hazardous-materials spill). In response to new principles and programs that have appeared over the last 5 years, this policy statement provides an update of the 2000 policy statement. The roles of both the pediatrician and public health agencies continue to be emphasized; only a coordinated effort by pediatricians and public health can ensure that the needs of children, including emergency protocols in schools or child care centers, decontamination protocols, and mental health interventions, will be successful.

Recognition of illness associated with covert chemical releases

Public health threats from intentional releases of chemicals into the environment (ie, chemical terrorism) are an increasing concern in the United States. Recent situations of deliberate contamination of food and beverages with chemicals highlight the need for health care providers and public health officials to be alert for adult and pediatric patients in their communities who have signs and symptoms consistent with chemical exposures. In an effort to increase knowledge of surveillance and preparedness for illness related to potential chemical releases, we provide guidance to health care providers and public health personnel for recognizing illnesses or patterns of illnesses that might be associated with the intentional, covert release of chemical agents. In this article, we will discuss 5 examples of outbreaks of illnesses after a covert chemical release, obstacles to recognition of these illnesses, clues (ie, epidemiological patterns and syndromic presentations) that might enhance the recognition of illnesses from a covert chemical release, and public health strategies to enhance the rapid identification of a chemical terrorism event.

N-methyl carbamate pesticide residues in conventional and organic infant foods available on the Canadian retail market, 2001–03

Seven parent N-methyl carbamate insecticides, in addition to two transformation products of aldicarb (aldicarb sulfoxide and aldicarb sulfone), and a single transformation product of carbofuran (3-hydroxycarbofuran) were measured in infant and junior foods available on the Canadian retail market between 2001 and 2003. Carbaryl and methomyl were the only analytes present at levels above the limits of detection in juice, cereals, fruit, vegetables or meat samples analysed. Carbaryl was the most frequently (7.6%) detected compound and concentrations ranged from 0.6 to 18 ng g-1. Detectable levels of carbaryl were most frequently found in foods prepared with fruit. Methomyl was detected (0.8 ng g-1) in one chicken with broth sample analysed in the present study. In all cases, the concentrations observed were orders of magnitude below the maximum residue limits established for these compounds in the corresponding raw food commodities in Canada (100-10 000 ng g-1). Dietary intakes of carbaryl and methomyl based on the consumption of infant foods tested ranged between 0.2-343 and 0.4-2.0 ng kg-1 body weight day-1, respectively.

Early Detection of Illness Associated With Poisonings of Public Health Significance

Since September 11, 2001, concern about potential terrorist attacks has increased in the United States. To reduce morbidity and mortality from outbreaks of illness from the intentional release of chemical agents, we examine data from the Toxic Exposure Surveillance System (TESS). TESS, a national system for timely collection of reports from US poison control centers, can facilitate early recognition of outbreaks of illness from chemical exposures. TESS data can serve as proxy markers for a diagnosis and may provide early alerts to potential outbreaks of covert events. We use 3 categories of information from TESS to detect potential outbreaks, including call volume, clinical effect, and substance-specific data. Analysis of the data identifies aberrations by comparing the observed number of events with a threshold based on historical data. Using TESS, we have identified several events of potential public health significance, including an arsenic poisoning at a local church gathering in Maine, the TOPOFF 2 national preparedness exercise, and contaminated food and water during the northeastern US blackout. Integration of poison control centers into the public health network will enhance the detection and response to emerging chemical threats. Traditionally, emergency physicians and other health care providers have used poison control centers for management information; their reporting to these centers is crucial in poisoning surveillance efforts.

N-methyl carbamate concentrations and dietary intake estimates for apple and grape juices available on the retail market in Canada

Infants and young children consume fruit juices and drinks at rates exceeding those of older children and adults. Carbamate pesticides are known to be used on a broad spectrum of crops, including orchard and vine crops such as apples and grapes. Concern over potential exposure to these acutely toxic pesticides by infants and young children has increased in the last decade. Liquid chromatography with fluorescence detection was used to determine the concentrations of seven N-methyl carbamates and three transformation products in domestic and imported apple and grape juices collected across Canada. Carbaryl was the most frequently (58.6%) detected N-methyl carbamate in juice samples studied. It was observed more frequently in grape juices than in apple or mixed juices. Oxamyl and methomyl were detected in apple juice samples, although they were below detection limits in all grape and mixed juice samples analysed. Maximum levels of carbaryl, methomyl and oxamyl were 93, 6.7 and 4.6 ng ml(-1), respectively. All other analytes were not present in any juice sample at concentrations above the method detection limit (0.3 ng ml(-1)). In all cases, N-methyl carbamate residues were well below the maximum residue limit established for apples and grapes in the Canadian Food and Drug Regulations. No estimated dietary intakes were above the acceptable daily intakes in any age-sex category, where an acceptable daily intake has been proposed. Carbaryl short-term intake estimates were calculated and all were below the proposed acute reference doses.

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.

Position of the American Dietetic Association: food and water safety

It is the position of the American Dietetic Association that the public has the right to a safe food and water supply. The Association supports collaboration among dietetics professionals, academics, representatives of the agriculture and food industries, and appropriate government agencies to ensure the safety of the food and water supply by providing education to the public and industry, promoting technologic innovation and applications, and supporting further research. Numerous bacterial, viral, and chemical food and water threats exist with certain populations such as the elderly, children, pregnant women, those in institutionalized settings, and the immune compromised being at high risk. Recent outbreaks of food and waterborne disease and threats of bioterrorism have focused attention on the safety of US food and water systems. The US government and other entities have developed programs to address challenges associated with maintaining food and water safety. Safety initiatives such as the Pathogen Reduction/Hazard Analysis Critical Point (HACCP), revisions to the Food Code, and the National Primary Drinking Water Regulations provide a framework to evaluate current and future challenges to the safety of food and water systems. Dietetics professionals should take a proactive role in ensuring that appropriate food and water safety practices are followed and can also assume major roles in food and water safety education and research.

An Outbreak of Food‐borne Illness Due to Methomyl Contamination

BACKGROUND

On December 26, 2002, 124 dinners took ill while eating lunch at a seafood restaurant in the town of Chiching in Kaohsiung municipality of Taiwan. Sixty-nine people were sent to the emergency departments of the Municipal Chiching Hospital and Yuan's General Hospital.

METHODS

We analyzed the clinical symptoms, detailed food history, and ingested amount of each food from 59 hospitalized adult patients and identified the source of the outbreak.

RESULTS

The median latency period from beginning eating to first symptoms was 5 min. Twenty-six symptoms and signs were recorded. The most commonly reported clinical effects were general weakness (84%), ataxia (82%), dizziness (82%), vomiting (80%), sweating (75%), floating sensation (71%), headache (69%), dyspnea (69%), and blurred vision (67%). Thirty-one patients had residual symptoms 7 days after ingestion. Of the six residual symptoms reported, the most frequent ones were dizziness (40%), poor appetite and dry mouth (11%), and gastrointestinal disturbance (11%). The presence of residual symptoms correlated with the severity of the initial complaints (p < 0.01). Almost all patients ate cooked rice (93%) and leaf vegetable stir-fried with crab claw (93%). The amount of each food eaten by the patients was not associated with the severity of symptoms (p > 0.05). High levels of methomyl in leaf vegetables of "leaf vegetables stir-fried with crab claws" (380 ppm) and fried mussels (1113 ppm) were found by the Food Inspection Center at the Department of Health. The food history and chemical analysis of the poison indicated methomyl was the cause of this outbreak. Twenty-four patients recovered completely within 7 days.

CONCLUSION

Food-related methomyl intoxication produced a rapid onset of significant clinical toxicity in 124 individuals. Based on the analysis of 55 adult patients, the most common effects were gait ataxia, dizziness, generalized weakness, and vomiting.

Electrochemical biosensors for environmental monitoring

Highly sensitive electrochemical biosensors offer precision, sensitivity, rapidity, and ease of operation for on-site environmental analysis. An electrochemical biosensor is an analytical device in which a specific biological recognition element (bioreceptor) is integrated within or intimately associated with an electrode (transducer) that converts the recognition event to a measurable electrical signal for the purpose of detecting a target compound (analyte) in solution. The signal generated allows both qualitative and quantitative measurements of an analyte in real time. In most cases, a miniaturized electrochemical cell contains a low volume of analyte, which is vital when dealing with hazardous materials and makes such devices ideal for environmental monitoring. This approach not only provides the means for on-site analysis but also removes the time delay and sample alteration that can occur during transport to a centralized laboratory. We first address the basic principles of electroanalytical measurement and the merger of electrochemistry and biology into a biosensing system, and then we discuss various environmental monitoring strategies involving this technology.