Shiga toxin-producing Escherichia coli O157:H7 outbreak associated with school field trips at a farm animal exhibit-Tennessee, September-October 2023.

AIMS: In October 2023, the Tennessee Department of Health identified an outbreak of Shiga toxin-producing Escherichia coli (STEC) O157:H7 infections among elementary school students who attended school field trips to the same farm animal exhibit. Our aim was to determine STEC source and prevent additional illnesses by initiating epidemiologic, laboratory and environmental investigations. METHODS AND RESULTS: We identified cases using laboratory-based surveillance and by surveying caregivers of children who attended the exhibit. Probable cases were defined as illness with abdominal cramps or diarrhoea after attendance; confirmed cases were laboratory-confirmed STEC infection in an attendee or household contact. A site visit was conducted, and event organizers were interviewed. Human stool, animal faeces and environmental samples were tested for STEC O157:H7 by real-time polymerase chain reaction (PCR), culture and whole-genome sequencing (WGS). Approximately 2300 elementary school students attended the animal exhibit during 2 days. Field trip activities included contact with different farm animal species, drinking pasteurized milk outside animal enclosures and eating lunch in a separate building onsite. We received survey responses from 399 caregivers for 443 (19%) animal exhibit attendees. We identified 9 confirmed and 55 probable cases with illness onset dates during 26 September to 12 October. Seven children aged 1-7 years were hospitalized. Four children aged 1-6 years experienced haemolytic uraemic syndrome; none died. Laboratory testing identified STEC O157:H7 by culture from eight human stool samples with 0-1 allele difference by WGS. Three environmental samples had Shiga toxin (stx 2) genes detected by PCR, but no STEC isolates were recovered by culture. CONCLUSIONS: This is the largest reported STEC O157:H7 outbreak associated with an animal exhibit in Tennessee. We identified opportunities for educating school staff, event organizers and families about zoonotic disease risks associated with animal contact and published prevention measures.

Restaurant and Staff Characteristics Related to Practices that Could Contribute to Cross-Contamination.

Foodborne illness is a persistent public health concern in the U.S.; over 800 foodborne illness outbreaks are reported to the Centers for Disease Control and Prevention (CDC) annually. Most of these outbreaks (60%) are linked with restaurants. Contamination of food with foodborne pathogens during preparation and storage is a significant contributing factor to many of these outbreaks. The CDC's Environmental Health Specialists Network (EHS-Net) collected data to identify restaurant characteristics, policies, and practices associated with contamination prevention practices. Data collectors interviewed managers and conducted kitchen observations in 312 restaurants across six EHS-Net sites in five states. Data collectors observed at least one food worker action that could lead to contamination in 63.1% of restaurants. The most frequently observed action that could lead to contamination was bare-hand or dirty glove contact with ready-to-eat food (35.9%). The estimated mean number of observed potential contamination actions was greater in restaurants that were independently owned (does not share a name and operations with other restaurants), did not require managers to be certified in food safety, did not have workers trained in food safety, did not have a handwashing policy, did not have a policy minimizing bare-hand contact with ready-to-eat foods, and had a manager with more than two years of experience at their current restaurant. These results suggest that to improve contamination prevention, the foodservice industry and food safety officials can consider supporting and encouraging strong food safety training and policies, particularly concerning hand hygiene, and targeting interventions to independent restaurants.

Observed Potential Cross-Contamination in Retail Delicatessens.

ABSTRACT: Listeria monocytogenes is a persistent public health concern in the United States and is the third leading cause of death from foodborne illness. Cross-contamination of L. monocytogenes (between contaminated and uncontaminated equipment, food, and hands) is common in delicatessens and likely plays a role in the foodborne illness associated with retail deli meats. In 2012, the Centers for Disease Control and Prevention's Environmental Health Specialists Network conducted a study to describe deli characteristics related to cross-contamination with L. monocytogenes. The study included 298 retail delis in six state and local health departments' jurisdictions and assessed how well deli practices complied with the U.S. Food and Drug Administration Food Code provisions. Among delis observed using wet wiping cloths for cleaning, 23.6% did not store the cloths in a sanitizing solution between uses. Observed potential cross-contamination of raw meats and ready-to-eat foods during preparation (e.g., same knife used on raw meats and ready-to-eat foods, without cleaning in between) was present in 9.4% of delis. In 24.6% of delis with a cold storage unit, raw meats were not stored separately from ready-to-eat products in containers, bins, or trays. A proper food safety management plan can reduce gaps in cross-contamination prevention and should include adopting procedures to minimize food safety risks, instituting training with instruction and in-person demonstrations and certifying staff on those procedures, and monitoring to ensure the procedures are followed.

Retail Deli Characteristics Associated with Sanitizing Solution Concentrations.

ABSTRACT: Listeria monocytogenes is commonly found in retail delicatessen environments. Proper types and concentrations of sanitizers must be used to eliminate this pathogen from surfaces and reduce the consumer's risk for infection. In 2012, the Environmental Health Specialists Network of the Centers for Disease Control and Prevention completed a study on practices in retail delis that can help prevent cross-contamination and growth of L. monocytogenes. The present study focuses on the sanitizing solution used in delis, given its importance to cleaning and reducing pathogen contamination in retail food environments. We identified deli, manager, and worker characteristics associated with use of improper concentrations of sanitizing solution to wipe down food contact surfaces; 22.8% of sanitizing solutions used for wiping food contact surfaces were at improper concentrations. Independent delis were more likely to use improper concentrations of sanitizing solution, as were delis that sold fewer chubs (plastic tubes of meat) per week. Use of improper sanitizing solution concentrations was associated with required food safety training for managers; additional analyses suggest that this relationship is significant for independent but not chain delis. Cleaning and sanitizing must be emphasized in food safety efforts focused on independent and smaller delis.

Restaurant Characteristics Associated With the Use of Specific Food-Cooling Methods.

Pathogen growth caused by improper or slow cooling of hot foods was a contributing factor in 504 of restaurant- and deli-related outbreaks in the U.S. from 1998-2008. Little is known, however, about restaurant cooling practices. To fill this gap, the Centers for Disease Control and Prevention's Environmental Health Specialists Network (EHS-Net) conducted an observational study to identify and understand factors that might determine which methods restaurants follow to rapidly cool food. These methods include refrigerating food at ≤41 °F, at shallow depths, and in containers that are ventilated, unstacked, and have space around them. EHS-Net personnel collected data through manager interviews and observation of cooling processes in 420 randomly selected restaurants. Regression analyses revealed characteristics of restaurants most likely to use the cooling methods assessed. These characteristics included ownership by restaurant chains, manager food safety training and certification, few foods cooled at a time, many meals served daily, and a high ratio of workers to managers. These findings suggest that regulatory food safety programs and the retail industry might improve cooling methods-and reduce outbreaks-by providing and encouraging manager food safety training and certification, and by focusing intervention efforts on independent and smaller restaurants.

Retail Deli Slicer Inspection Practices: An EHS-Net Study.

The Centers for Disease Control and Prevention (CDC) estimates that 3,000 people die in the United States each year from foodborne illness, and Listeria monocytogenes causes the third highest number of deaths. Risk assessment data indicate that L. monocytogenes contamination of particularly delicatessen meats sliced at retail is a significant contributor to human listeriosis. Mechanical deli slicers are a major source of L. monocytogenes cross-contamination and growth. In an attempt to prevent pathogen cross-contamination and growth, the U.S. Food and Drug Administration (FDA) created guidance to promote good slicer cleaning and inspection practices. The CDC's Environmental Health Specialists Network conducted a study to learn more about retail deli practices concerning these prevention strategies. The present article includes data from this study on the frequency with which retail delis met the FDA recommendation that slicers should be inspected each time they are properly cleaned (defined as disassembling, cleaning, and sanitizing the slicer every 4 h). Data from food worker interviews in 197 randomly selected delis indicate that only 26.9% of workers ( n = 53) cleaned and inspected their slicers at this frequency. Chain delis and delis that serve more than 300 customers on their busiest day were more likely to have properly cleaned and inspected slicers. Data also were collected on the frequency with which delis met the FDA Food Code provision that slicers should be undamaged. Data from observations of 685 slicers in 298 delis indicate that only 37.9% of delis ( n = 113) had slicers that were undamaged. Chain delis and delis that provide worker training were more likely to have slicers with no damage. To improve slicer practices, food safety programs and the retail food industry may wish to focus on worker training and to focus interventions on independent and smaller delis, given that these delis were less likely to properly inspect their slicers and to have undamaged slicers.

Restaurant Food Allergy Practices - Six Selected Sites, United States, 2014.

Food allergies affect an estimated 15 million persons in the United States (1), and are responsible for approximately 30,000 emergency department visits and 150-200 deaths each year (2). Nearly half of reported fatal food allergy reactions over a 13-year period were caused by food from a restaurant or other food service establishment (3). To ascertain the prevalence of food allergy training, training topics, and practices related to food allergies, CDC's Environmental Health Specialists Network (EHS-Net), a collaborative forum of federal agencies and state and local health departments with six sites, interviewed personnel at 278 restaurants. Fewer than half of the 277 restaurant managers (44.4%), 211 food workers (40.8%), and 156 servers (33.3%) interviewed reported receiving food allergy training. Among those who reported receiving training, topics commonly included the major food allergens and what to do if a customer has a food allergy. Although most restaurants had ingredient lists for at least some menu items, few had separate equipment or areas designated for the preparation of allergen-free food. Restaurants can reduce the risk for allergic reactions among patrons by providing food allergy training for personnel and ingredient lists for all menu items and by dedicating equipment and areas specifically for preparing allergen-free food.

Retail Deli Slicer Cleaning Frequency--Six Selected Sites, United States, 2012.

Listeria monocytogenes (Listeria) causes the third highest number of foodborne illness deaths (an estimated 255) in the United States annually, after nontyphoidal Salmonella species and Toxoplasma gondii (1). Deli meats are a major source of listeriosis illnesses, and meats sliced and packaged at retail delis are the major source of listeriosis illnesses attributed to deli meat (4). Mechanical slicers pose cross-contamination risks in delis and are an important source of Listeria cross-contamination. Reducing Listeria contamination of sliced meats in delis will likely reduce Listeria illnesses and outbreaks. Good slicer cleaning practices can reduce this foodborne illness risk. CDC's Environmental Health Specialists Network (EHS-Net) studied how often retail deli slicers were fully cleaned (disassembled, cleaned, and sanitized) at the Food and Drug Administration (FDA) Food Code-specified minimum frequency of every 4 hours and examined deli and staff characteristics related to slicer cleaning frequency. Interviews with staff members in 298 randomly-selected delis in six EHS-Net sites showed that approximately half of delis fully cleaned their slicers less often than FDA's specified minimum frequency. Chain-owned delis and delis with more customers, more slicers, required manager food safety training, food safety-knowledgeable workers, written slicer-cleaning policies, and food safety-certified managers fully cleaned their slicers more frequently than did other types of delis, according to deli managers or workers. States and localities should require deli manager training and certification, as specified in the FDA Food Code. They should also consider encouraging or requiring delis to have written slicer-cleaning policies. Retail food industry leaders can also implement these prevention efforts to reduce risk in their establishments. Because independent and smaller delis had lower frequencies of slicer cleaning, prevention efforts should focus on these types of delis.

Food Allergy Knowledge and Attitudes of Restaurant Managers and Staff: An EHS-Net Study.

Dining outside of the home can be difficult for persons with food allergies who must rely on restaurant staff to properly prepare allergen-free meals. The purpose of this study was to understand and identify factors associated with food allergy knowledge and attitudes among restaurant managers, food workers, and servers. This study was conducted by the Environmental Health Specialists Network (EHS-Net), a collaborative forum of federal, state, and local environmental health specialists working to understand the environmental factors associated with food safety issues. EHS-Net personnel collected data from 278 randomly selected restaurants through interviews with restaurant managers, food workers, and servers. Results indicated that managers, food workers, and servers were generally knowledgeable and had positive attitudes about accommodating customers' food allergies. However, we identified important gaps, such as more than 10% of managers and staff believed that a person with a food allergy can safely consume a small amount of that allergen. Managers and staff also had lower confidence in their restaurant's ability to properly respond to a food allergy emergency. The knowledge and attitudes of all groups were higher at restaurants that had a specific person to answer food allergy questions and requests or a plan for answering questions from food allergic customers. However, food allergy training was not associated with knowledge in any of the groups but was associated with manager and server attitudes. Based on these findings, we encourage restaurants to be proactive by training staff about food allergies and creating plans and procedures to reduce the risk of a customer having a food allergic reaction.

Quantitative data analysis to determine best food cooling practices in U.S. restaurants.

Data collected by the Centers for Disease Control and Prevention (CDC) show that improper cooling practices contributed to more than 500 foodborne illness outbreaks associated with restaurants or delis in the United States between 1998 and 2008. CDC's Environmental Health Specialists Network (EHS-Net) personnel collected data in approximately 50 randomly selected restaurants in nine EHS-Net sites in 2009 to 2010 and measured the temperatures of cooling food at the beginning and the end of the observation period. Those beginning and ending points were used to estimate cooling rates. The most common cooling method was refrigeration, used in 48% of cooling steps. Other cooling methods included ice baths (19%), room-temperature cooling (17%), ice-wand cooling (7%), and adding ice or frozen food to the cooling food as an ingredient (2%). Sixty-five percent of cooling observations had an estimated cooling rate that was compliant with the 2009 Food and Drug Administration Food Code guideline (cooling to 41 °F [5 °C] in 6 h). Large cuts of meat and stews had the slowest overall estimated cooling rate, approximately equal to that specified in the Food Code guideline. Pasta and noodles were the fastest cooling foods, with a cooling time of just over 2 h. Foods not being actively monitored by food workers were more than twice as likely to cool more slowly than recommended in the Food Code guideline. Food stored at a depth greater than 7.6 cm (3 in.) was twice as likely to cool more slowly than specified in the Food Code guideline. Unventilated cooling foods were almost twice as likely to cool more slowly than specified in the Food Code guideline. Our data suggest that several best cooling practices can contribute to a proper cooling process. Inspectors unable to assess the full cooling process should consider assessing specific cooling practices as an alternative. Future research could validate our estimation method and study the effect of specific practices on the full cooling process.

Handling practices of fresh leafy greens in restaurants: receiving and training.

Multiple foodborne illness outbreaks have been associated with the consumption of fresh produce. Investigations have indicated that microbial contamination throughout the farm-to-fork continuum often contributed to these outbreaks. Researchers have hypothesized that handling practices for leafy greens in restaurants may support contamination by and proliferation and amplification of pathogens that cause foodborne illness outbreaks. However, limited data are available on how workers handle leafy greens in restaurants. The purpose of this study was to collect descriptive data on handling practices of leafy greens in restaurants, including restaurant characteristics, types of leafy greens used, produce receipt, and food safety training and certification. As a federal collaborative partner with the Environmental Health Specialists Network (EHS-Net) of the Centers for Disease Control and Prevention, the U.S. Food and Drug Administration (FDA) recommended that EHS-Net participants survey handling practices for leafy greens in restaurants. The recommendations in the FDA's Guide to Minimize Microbial Food Safety Hazards of Leafy Greens are significant to this study for comparison of the results. The survey revealed that appropriate handling procedures assist in the mitigation of other unsafe handling practices for leafy greens. These results are significant because the FDA guidance for the safe handling of leafy greens was not available until 2009, after the survey had been completed. The information provided from this study can be used to promote additional efforts that will assist in developing interventions to prevent future foodborne illness outbreaks associated with leafy greens.

Restaurant food cooling practices.

Improper food cooling practices are a significant cause of foodborne illness, yet little is known about restaurant food cooling practices. This study was conducted to examine food cooling practices in restaurants. Specifically, the study assesses the frequency with which restaurants meet U.S. Food and Drug Administration (FDA) recommendations aimed at reducing pathogen proliferation during food cooling. Members of the Centers for Disease Control and Prevention's Environmental Health Specialists Network collected data on food cooling practices in 420 restaurants. The data collected indicate that many restaurants are not meeting FDA recommendations concerning cooling. Although most restaurant kitchen managers report that they have formal cooling processes (86%) and provide training to food workers on proper cooling (91%), many managers said that they do not have tested and verified cooling processes (39%), do not monitor time or temperature during cooling processes (41%), or do not calibrate thermometers used for monitoring temperatures (15%). Indeed, 86% of managers reported cooling processes that did not incorporate all FDA-recommended components. Additionally, restaurants do not always follow recommendations concerning specific cooling methods, such as refrigerating cooling food at shallow depths, ventilating cooling food, providing open-air space around the tops and sides of cooling food containers, and refraining from stacking cooling food containers on top of each other. Data from this study could be used by food safety programs and the restaurant industry to target training and intervention efforts concerning cooling practices. These efforts should focus on the most frequent poor cooling practices, as identified by this study.

Recordkeeping practices of beef grinding activities at retail establishments.

Ground beef has been implicated as a transmission vehicle in foodborne outbreaks of infection with pathogens such as Escherichia coli O157:H7 and Salmonella. During outbreak investigations, traceback of contaminated beef to the producing facility is often unsuccessful because of inadequate recordkeeping at retail establishments that grind beef products. We conducted a survey in three states participating in the Environmental Health Specialists Network to describe beef grinding and recordkeeping practices at retail establishments. In each establishment that maintained grinding logs, three randomly selected records were reviewed to determine whether important data elements for traceback investigations were recorded. One hundred twenty-five stores were surveyed, of which 60 (49%) kept grinding logs, including 54 (74%) of 73 chain stores and 6 (12%) of 51 independent stores. One hundred seventy-six grinding records from 61 stores were reviewed. Seventy-three percent of the records included the establishment code of the source beef, 72% included the grind date and time, and 59% included the lot number of the source beef. Seventy-five percent of records noted whether trimmings were included in grinds, and 57% documented cleanup activities. Only 39 (22%) records had all of these variables completed. Of stores that did not keep grinding logs, 40% were unaware of their purpose. To facilitate effective and efficient traceback investigations by regulatory agencies, retail establishments should maintain records more detailed and complete of all grinding activities.

Food worker hand washing practices: an observation study.

Improvement of food worker hand washing practices is critical to the reduction of foodborne illness and is dependent upon a clear understanding of current hand washing practices. To that end, this study collected detailed observational data on food worker hand washing practices. Food workers (n = 321) were observed preparing food, and data were recorded on specific work activities for which hand washing is recommended (e.g., food preparation, handling dirty equipment). Data were also recorded on hand washing behaviors that occurred in conjunction with these work activities. Results indicated that workers engaged in approximately 8.6 work activities per hour for which hand washing is recommended. However, workers made hand washing attempts (i.e., removed gloves, if worn, and placed hands in running water) in only 32% of these activities and washed their hands appropriately (i.e., removed gloves, if worn, placed hands in running water, used soap, and dried hands) in only 27% of these work activities. Attempted and appropriate hand washing rates varied by work activity--they were significantly higher in conjunction with food preparation than other work activities (46 versus < or = 37% for attempted hand washing; 41 versus < or = 30% for appropriate hand washing) and were significantly lower in conjunction with touching the body than other work activities (13 versus > or = 27% for attempted hand washing; 10 versus > or = 23% for appropriate hand washing). Attempted and appropriate hand washing rates were significantly lower when gloves were worn (18 and 16%) than when gloves were not worn (37 and 30%). These findings suggest that the hand washing practices of food workers need to be improved, glove use may reduce hand washing, and restaurants should consider reorganizing their food preparation activities to reduce the frequency with which hand washing is needed.