Cyclospora is a parasite composed of one cell, too small to be seen without a microscope. The organism was previously thought to be a blue-green alga or a large form of CryptosporidiumCyclospora cayetanensis is the only species of this organism found in humans. 

Cyclosporiasis is an intestinal illness caused by the parasite Cyclospora cayetanensis, which is transmissible by ingestion of fecally contaminated food or water.[1] Cyclosporiasis is most common in tropical and subtropical regions of the world. In the United States, foodborne outbreaks of cyclosporiasis have been linked to various types of imported fresh produce (e.g., basil, raspberries, and snow peas). Validated molecular typing tools, which could facilitate detection and investigation of outbreaks, are not yet available for C. cayetanensis.

Outbreaks of cyclosporiasis in humans have been reported mostly from North America, from the infection sources of contaminated fresh food products, such as soft fruits (raspberries), leafy vegetables (coriander, basil, and mixed salad), and herbs. Soil is another possible infection source, particularly in areas with poor environmental sanitation.[2]

The Centers for Disease Control and Prevention (CDC) has been conducting national surveillance for cyclosporiasis since it became a nationally notifiable disease in January 1999. As of 2015, cyclosporiasis was a reportable condition in 42 states, the District of Columbia, and New York City (NYC). Health departments voluntarily notify CDC of cases of cyclosporiasis through the National Notifiable Diseases Surveillance System and submit additional case information using the CDC cyclosporiasis case report form or the Cyclosporiasis National Hypothesis Generating Questionnaire (CNHGQ).[3]

While cyclosporiasis cases are reported year-round in the United States, cyclosporiasis acquired in the United States (i.e., “domestically acquired,” or cases of cyclosporiasis that are not associated with travel to a country that is considered endemic for Cyclospora) is most common during the spring and summer months. The exact timing and duration of U.S. cyclosporiasis seasons can vary, but reports tend to increase starting in May. In 2020, multiple outbreaks of cyclosporiasis were identified and found to be linked to different produce items. As of September 23, 2020, the CDC documented 1,241 laboratory-confirmed cases of cyclosporiasis in people who had no history of international travel during the 14-day period before illness onset.[4]

What are the typical symptoms of Cyclospora infection?

Cyclospora infects the small intestine (bowel) and usually causes watery diarrhea, bloating, increased gas, stomach cramps, and loss of appetite, nausea, low-grade fever, and fatigue. In some cases, vomiting, explosive diarrhea, muscle aches, and substantial weight loss can occur. Some people who are infected with Cyclospora do not have any symptoms. The time between becoming infected and becoming ill is usually about one week. If not treated, the illness may last from a few days up to six weeks. Symptoms also may recur one or more times (relapse). In addition, people who have previously been infected with Cyclospora can become infected again.[5]

Where does Cyclospora come from?

The modes of transmission of C. cayetanensis are still not completely documented, although fecal–oral transmission is the major route. Direct person-to-person transmission is unlikely. Indirect transmission can occur if an infected person contaminates the environment, the oocysts sporulate under the right conditions, and then contaminated food and water are ingested. The role of soil in transmission has also been proposed. The relative importance of these various modes of transmission and sources of infection is not known.[6]

The dissemination of infective Cyclospora oocysts via water, soil, and unprocessed foods (e.g., fruits and vegetables, including ready-to-eat salads) is enabled by their small size (8–10 μm), low specific gravity, and high infectivity. Such oocysts can survive for weeks to months in water and food, depending on the environmental temperature, and are resistant to the routine sanitization or chemical disinfection procedures used in irrigation systems, recreational waters, or drinking water treatment plants.[7]

How is Cyclospora diagnosed?

Cyclosporiasis is usually diagnosed symptomatically in clinical settings, including the presence of watery diarrhea, abdominal cramping, and bloating. In untreated, immunocompetent people, the diarrhea can last from days to weeks to a month or more, and can wax and wane, with variable oocyst shedding. Oocysts can continue to be shed (intermittently or continuously) by non-symptomatic people, and symptoms can also persist in the absence of oocysts in feces. In a clinical context, conventional diagnosis usually involves microscopic examination of intestinal tissue biopsy sections, stool samples for the presence of developmental stages of Cyclospora, or advanced molecular testing for DNA. Improved specificity and sensitivity have been possible largely through the use of PCR, which enables the specific amplification of genetic loci from tiny amounts of genomic DNA of Cyclospora. Because of the intermittent nature of oocyst shedding and the low numbers of this stage in feces, it is recommended that multiple stool samples be collected at 2–3-day intervals over a period of more than a week, to increase the likelihood of identifying the disease microscopically.[8]

What are the serious and long-term risks of Cyclospora infection?

Cyclospora has been associated with a variety of chronic complications such as malabsorption, reactive arthritis, and cholecystitis (inflammation of the gallbladder). Since Cyclospora infections tend to respond to the appropriate treatment, complications are more likely to occur in individuals who are not treated or not treated promptly. Extraintestinal infection also appears to occur more commonly in individuals with a compromised immune system.[9]

Although human cyclosporiasis is usually not fatal in developed countries such as the United States, protracted diarrhea often leads to dehydration, particularly in infants who are at greatest risk of severe dehydration and death, especially if cyclosporiasis is complicated by infections with other pathogens (viral, bacterial, or parasitic—e.g., Cryptosporidium and Giardia), malnutrition, or malabsorption, particularly in underprivileged communities.[10]

According to the CDC[11], the recommended treatment is a combination of two antibiotics, trimethoprim-sulfamethoxazole, also known as Bactrim, Septra, or Cotrim. It is advisable for people who have diarrhea to also rest and drink plenty of fluids.


[1]           Casillas, S. M., Hall, R. L., & Herwaldt, B. L. (2019). Cyclosporiasis Surveillance – United States, 2011-2015. Morbidity and mortality weekly report. Surveillance summaries (Washington, D.C. : 2002)68(3), 1–16. https://doi.org/10.15585/mmwr.ss6803a1

[2]           Giangaspero, A., & Gasser, R. B. (2019). Human cyclosporiasis. The Lancet Infectious Diseases, 19(7), e226–e236. https://doi.org/10.1016/S1473-3099(18)30789-8

[3]           Casillas, Ibid, Note 1 at Page 1.

[4]           CDC. (2020, September 24). Cyclosporiasis Outbreak Investigations – United States, 2020. Centers for Disease Control and Prevention. https://www.cdc.gov/parasites/cyclosporiasis/outbreaks/2020/seasonal/index.html  

[5]           Cyclosporiasis – Disease. (2018, May 11). https://www.cdc.gov/parasites/cyclosporiasis/disease.html

[6]           Almeria S, Cinar HN, Dubey JP. Cyclospora cayetanensis and Cyclosporiasis: An Update. Microorganisms. 2019; 7(9):317.

[7]           Giangaspero, Ibid, Note 2 at Page 1.

[8]           Giangaspero, Ibid, Note 2 at Page 3-4.

[9]           CDC. (2020, October 21). CDC – Cyclosporiasis – Resources for Health Professionals. Centers for Disease Control and Prevention. https://www.cdc.gov/parasites/cyclosporiasis/health_professionals/index.html

[10]         Giangaspero, Ibid, Note 2 at Page 2.

[11]         CDC. (2020, September 17). CDC – Cyclosporiasis – General Information – Cyclosporiasis FAQshttps://www.cdc.gov/parasites/cyclosporiasis/gen_info/faqs.html

Summary

Public Health is investigating an outbreak of Shiga toxin-producing E. coli O157:H7 (also known as STEC). Three of the five people who got sick had testing that matched by genetic fingerprinting. This means they most likely got sick from the same source. Based on information collected, we found one common source for all sick people which was a store-made guacamole purchased at PCC Community Markets – West Seattle Co-op on February 10, 2024. Even though we think this is the most likely source of illness, we do not know for certain. We did not find out how the guacamole might have been contaminated with STEC and did not have any left to test. This outbreak appears to be over.

Illnesses

Since February 21, 2024, Public Health has learned about five people who got sick between February 14 – February 28, 2024. All five people had symptoms of STEC, including diarrhea (often bloody), stomach cramping, nausea, and vomiting. We have not found any employees sick with symptoms of STEC from PCC Community Markets – West Seattle Co-op.

Public Health actions

Disease Investigators conducted in-depth interviews with the five sick people to find common exposures and help prevent ongoing spread of STEC. Environmental Health Investigators visited the grocery on March 15, 2024. Investigators reviewed with restaurant management the requirement that staff who have symptoms of vomiting and diarrhea are not allowed to work until they are symptom-free for at least 24 hours. Investigators provided education about preventing the spread of STEC — including proper handwashing, preventing bare hand contact with ready-to-eat foods, and preventing cross contamination between raw meat and ready-to-eat food during food preparation. When food workers have STEC, they need further testing before going back to work to make sure they are not contagious.

Laboratory testing

Four people who became sick had testing that was positive for STEC O157:H7. Three people also had further testing showing they matched by whole genome sequencing or WGS (like genetic fingerprinting) at the Washington State Public Health Laboratory. One person who became sick did not have any testing done.

CDC, public health and regulatory officials in several states, the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS), and the U.S. Food and Drug Administration (FDA) investigated a multistate outbreak of Listeria monocytogenes infections.

Epidemiologic and laboratory data showed that meat and cheese from deli counters made people sick. A single deli or food source was not yet identified.

A total of 16 people infected with the outbreak strain of Listeria were reported from 6 states. Sick people’s samples were collected from April 17, 2021, to September 29, 2022. The true number of sick people in this outbreak is likely higher than the number reported, and the outbreak may not have been limited to the states with known illnesses. This is because some people recover without medical care and are not tested for Listeria.

Public health officials collected many different types of information from sick people, including their age, race, ethnicity, other demographics, and the foods they ate in the month before they got sick. This information provided clues to help investigators identify the source of the outbreak.

Sick people ranged in age from 38 to 92 years, with a median age of 74, and 62% were male. Of 15 people with race or ethnicity information available, 13 were White, 1 was African American/Black, 1 was Asian, and no one reported Hispanic ethnicity. Eleven people were of Eastern European background or spoke Russian.

Of 14 people with healthcare information available, 13 were hospitalized. One person got sick during their pregnancy, resulting in pregnancy loss. Additionally, one death was reported from Maryland.

Of the 12 people interviewed, 11 reported eating meat or cheese from deli counters. Among seven sick people in New York, five bought sliced deli meat or cheese from at least one location of NetCost Market, a grocery store chain that sells international foods. Sick people from other states purchased deli meats or cheeses from other delis.

NetCost Market delis are unlikely to be the only source of illnesses because some sick people in the outbreak did not shop at a NetCost Market. A contaminated food likely introduced the outbreak strain of Listeria into delis in multiple states.

Public health investigators used the PulseNet system to identify illnesses that were part of this outbreak. CDC PulseNet manages a national database of DNA fingerprints of bacteria that cause foodborne illnesses. DNA fingerprinting is performed on bacteria using a method called whole genome sequencing (WGS).

WGS showed that bacteria from sick people’s samples were closely related genetically. This suggests that people in this outbreak got sick from the same food.

In 2021, health officials in New York state and New York City found the outbreak strain of Listeria in several environmental and food samples:

  • Environmental samples from a NetCost Market deli in Brooklyn
  • Several open packages of mortadella and ham that were sliced at the same NetCost Market deli in Brooklyn
  • Sliced salami that a sick person bought from a NetCost Market deli in Staten Island

NetCost Market voluntarily closed the deli temporarily in Brooklyn after New York officials [PDF – 2 pages] notified them about the sampling results. NetCost Market performed a deep cleaning and then reopened the deli in Brooklyn after further environmental testing did not  find Listeria.

In September 2022, the outbreak strain was found at the same Brooklyn NetCost Market deli; however, the most recent illness with NetCost Market exposure was in October 2021. After a deep cleaning, additional environmental testing did not find Listeria in the deli.

Data showed that deli meat and cheese bought at deli counters in multiple states were the likely sources of this outbreak.

  • Of 12 people interviewed, 11 reported eating meat or cheese from deli counters.
  • The outbreak strain of Listeria was found in open packages of mortadella, ham, and salami sliced at the deli, as well as a deli in Brooklyn, New York.

A single deli or food source was not yet identified. It is difficult for investigators to identify the specific source of outbreaks linked to deli meats and cheeses. This is because Listeria spreads easily between food and the deli environment, and it can live for a long time in deli display cases and on equipment. A contaminated food likely introduced the outbreak strain of Listeria into delis in multiple states.

According to Food Safety News, the outbreak strain has been found at a farm that supplied the milk used to make Mrs Kirkham’s unpasteurized cheese, which was linked to an E. coli outbreak in the UK.

In total, 36 confirmed and one probable Shiga toxin-producing E. coli (STEC) O145 infections have been reported, with 29 in England and eight in Scotland since late July 2023, with most falling ill in November. The last reported primary patient had symptom onset on Dec. 23, 2023.

Twenty patients were female, with ages of all cases ranging from 7 to 81. Of the 31 patients with available information, 20 had bloody diarrhea, 15 were admitted to the hospital, and four also attended the hospital for their symptoms. One person developed hemolytic uremic syndrome (HUS) and later died.

An investigation into the outbreak by the UK Health Security Agency (UKHSA), the local authority, Public Health Scotland, Food Standards Agency (FSA), Food Standards Scotland (FSS) and the Animal Plant Health Agency (APHA) is nearly completed.

During an APHA visit to the farm, 28 environmental samples were collected, including fresh and aged cattle feces from various locations on site, and two water trough sediment samples. Two cattle fecal samples tested positive for STEC O145. These isolates were genetically indistinguishable from the outbreak strain detected in human cases.

Summary

On October 3, 2023, the Tennessee Department of Health (TDH) Northeast Regional Office was notified of two cases of Shiga toxin-producing Escherichia coli (STEC). Over the next two weeks a total of ninepatients with STEC infections were reported, seven (78%) were hospitalized, and four (44%) developed hemolytic uremic syndrome (HUS), a type of kidney failure. TDH initiated an outbreak investigation in collaboration with colleagues from the Sullivan County Regional Health Department and the state Foodborne and Enteric Disease program. All patients, or their parents, were interviewed with a standardized case report form specific for STEC infections.

Questions about exposures known to be associated with STEC, including specific food items, restaurants, water sources, travel, pets, and other animal exposures were included.

Of nine laboratory-confirmed cases of STEC, eight (89%) were among children (age range: 1-7 years). All HUS cases were among children (age range: 1-6 years). Four (44%) cases occurred following attendanceat the same live animal exhibit and five (56%) occurred among household contacts of children who were illafter attending the animal exhibit. Whole genome sequencing patterns for STEC O157:H7 were closely related, indicative of a common exposure. The common exposure reported among the nine patients with STEC infections was attending the animal exhibit or being a household contact of an attendee.

The animal exhibit included animal species from different farms. Cattle, sheep, goats, pigs, rabbits, a pony, and poultry were on display. Approximately 2,300 elementary school students (primarily kindergarten and second grade students) from Washington and Sullivan counties attended the event on September 26 and 27, 2023. Students were supervised by teachers and chaperones. Students were allowed to touch animals in certain areas of the exhibit. Milk was reportedly served in individual-sized cartons after students milked an artificial cow. Food (pizza) was served in a separate, enclosed building away from the animal exhibit. Temporary handwashing stations were reportedly available outside the exhibit area, and hand sanitizer was available at various locations. The extent to which handwashing was supervised for all students is unknown.

To define the source of STEC O157:H7 exposure and to inform prevention recommendations, health department officials performed an epidemiologic study, environmental sampling, and animal testing. An online survey was sent to parents of the children who attended the animal exhibit. Questions asked about illnesses after attending the exhibit, subsequent household illnesses, and activities and behaviors (e.g.,handwashing, animal contact, foods eaten). Parents or guardians that participated in the survey provided information for 443 persons who had attended the event. From information provided on the survey, or directly to the health departments, an additional 55 people were identified who experienced diarrhea or abdominal cramps after attending the exhibit but were not tested for STEC. Twenty-three household contacts with gastrointestinal illnesses after a child attended the exhibit were identified. None of these persons reported being hospitalized, although some accessed healthcare. Three environmental samples were positive for a gene associated with STEC but the outbreak strain of STEC O157:H7 was not isolated.

Health department officials implemented control measures including communication of animal contact risk and prevention strategies with schools, families, healthcare providers, and event organizers. Communications included:

  • Letters to parents were sent on October 6 and 9. These included links to information on

E. coli and safety at animal exhibits.

  • E. coli (Escherichia coli) | E. coli | CDC
    • Stay Healthy at Animal Exhibits | Healthy Pets, Healthy People | CDC
  • Letters to primary care and emergency medicine clinicians were sent October 6–10 to increaseawareness of the outbreak, and diagnosis and management of STEC and HUS.
  • Shiga Toxin–Producing Escherichia coli and the Hemolytic–Uremic Syndrome (N Engl J Med 2023; 389:1402-1414)
  • Prevention recommendations were shared during October 24–26 at meetings with event organizers and other animal exhibitors.
  • Compendium of Measures to Prevent Disease Associated with Animals in Public Settings,2023 from The National Association of State Public Health Veterinarians Animal Contact Compendium Committee, available at: http://www.nasphv.org/Documents/AnimalsInPublicSettings2023.pdf

Background

On October 3, 2023, the Tennessee Department of Health (TDH) Northeast Regional Office (NERO) notified the Foodborne and Enteric Disease (FED) program of two Shiga toxin-producing Escherichia coli (STEC) cases reported by a healthcare center. Both children reported attending the same “farm days” live animal exhibit prior to illness onset. The “farm days” event was held September 26–27 for pre-K, kindergarten, and 2nd gradestudents from Washington County, Bristol City (TN), Kingsport City, and Sullivan County school districts. After identifying this common exposure, the FED program, NERO, and Sullivan County Regional Health Department initiated epidemiologic, environmental, and laboratory investigations to confirm the outbreak, describe the source, and prevent further disease transmission.

Methods

Epidemiology

All persons with laboratory-confirmed STEC infection, or their parents/guardians, were interviewed with a standardized case report form specific for STEC. Data were collected on potential exposures known to be associated with STEC, including specific food items, restaurants, special events, water sources, travel, pets, and other animal exposures.

Event organizers provided a list of school classes that participated in the event. Health department staff created an event-specific online survey for case finding and exposure assessment. Questions about “farm days” animal exhibit attendance, various risk and prevention activities, and illness were included. School districts sent the survey during October 9 12 to parents of children in classes that participated in the animal exhibit. The survey was open until October 27, 2023.

Cases were classified using the following outbreak case definitions which were adapted from the Council ofState and Territorial Epidemiologists surveillance case definitions (CSTE 2018):

Confirmed case:

Primary Confirmed Case: Laboratory-confirmed STEC infection in a person with diarrheal illness within 10 days of attending the animal exhibit.

Secondary Confirmed Case: Laboratory-confirmed STEC infection in a person with illness onset after a household member attended the animal exhibit.

Probable case: Diarrhea2 and/or abdominal cramps in a person who attended the animal exhibit within the 10 days before becoming ill, and who was not tested for STEC.

Suspect case: Gastrointestinal illness in a household contact of a child who attended the animal exhibit with illness onset after the event and who does not meet probable or confirmed outbreak case criteria.

Data were collected and stored in REDCap Electronic Data Capture tools hosted at TDH. Odds ratios with 95% confidence intervals were calculated to assess the likelihood of different exposures at the exhibit being associated with reported illnesses. Analyses were conducted using SAS version 9.4 (SAS Institute, Inc.).

Environmental Health

On October 5, health department staff visited the event site and conducted an environmental assessment that included collecting environmental samples from animal areas for microbiologic testing. From October 10–13, health department staff conducted additional environmental sampling of some animals and animal areas at farms that had on exhibit. On October 26, health department staff again visited the event site to review the environmental assessment. A total of 31 environmental samples were collected by the health department during site visits. All samples were delivered to the Tennessee state public health laboratory (SPHL).

Laboratory

Clinical samples received at the SPHL were tested first by polymerase chain reaction (PCR) for stx1 and stx2 genes associated with Shiga toxin production. Isolation of E. coli by culture was attempted at the SPHL for all clinical specimens. Environmental samples were tested by the SPHL for stx1 and stx2 genes and culture. Environmental samples were also sent by the SPHL to the United States Department of Agriculture (USDA) Agro ecosystem Management Research Unit for isolation of STEC. Isolates cultured by the USDA that were suspected to be E. coli O157 were sent to the SPHL for further identification. E. coli O157 isolates identified in clinical or environmental samples had whole genome sequencing (WGS) performed at the SPHL.

Results

Epidemiology

Nine confirmed, 55 probable, and 23 suspect cases were identified. Of nine confirmed cases, four were primary and five were secondary cases. Seven children were hospitalized and four developed HUS. There were no deaths. Among nine confirmed cases, five (56%) occurred in males and ages ranged from 1 to 34 years. Among four HUS cases, two (50%) occurred in males and ages ranged from 1 to 6 years. Among 55 probable cases, 29 (53%) occurred in males and median age was 5 (interquartile range: 5–7) years. Illness onset dates occurred between September 26 and October 12

Approximately 2,300 children attended the exhibit and parents or guardians for 443 persons responded to the survey (response rate = 19%). None of the surveyed persons who reported diarrheal illness reported being hospitalized, although some were evaluated in healthcare clinics or emergency departments. Analysis of reported handwashing and animal contact among persons who attended the event and became ill and those who attended the event and didn’t become ill found animal contact increased risk (OR 2.38)and handwashing decreased risk (OR 0.59). Notably, neither of these risk factors reached statistical significance in the case- control analysis.

Environmental Health

The exhibit occurred during September 26–27 and included animals from several area farms. Animals on exhibit included cattle, sheep, goats, pigs, rabbits, a pony, and poultry.

Approximately 2,300 elementary school students attended (primarily kindergarten and second grade students) from Washington and Sullivan counties. Students were supervised by teachers and chaperones. After students visited various live animal stations, they could milk an artificial cow. Children were then offered pasteurized milk in a sealed individual-sized carton which they could open and drink on bleachers overlooking the animal exhibits. Fixed and temporary handwashing stations were reportedly available outside the exhibit area, and hand sanitizer was available at various locations. The extent to which handwashing was supervised for all students is unknown. Children were then served pizza and cookies in a separate, enclosed building away from the animal exhibit.

Fifteen environmental samples were collected from bedding material, feces, and surfaces in animal petting and observation areas during the environmental assessment on October 5. Sampled areas included pig, calf, cow, chicken, rabbit, goat, and sheep displays. Remaining feces from goat, sheep, and cow displays were collected. No animals were present when samples were collected. During October 10-13, health department staff collected another 16 samples from cooperating farms which had animals on display. These samples included manure and rectal samples from cow, sheep, and pig farms that had provided animals. Additionally, two shoe samples from a child who attended the event were collected.

Laboratory

The SPHL tested 18 stool samples from 16 ill persons that either attended the exhibit or were household contacts of a child who attended the exhibit. Nine specimens from eight persons had STEC O157:H7 isolated by culture and underwent WGS.For one specimen from a person with laboratory confirmed STEC by PCR, £. coli was not isolated by culture. Wholegenome sequencing results indicated that isolates were closely related (0-1alleles) with an average of 4 SNPs difference between isolates (range= 0-8 SNPs) (Figure 2). One child who attended the exhibit tested positive for both STEC O157:H7 and astro virus. Six specimens from five other persons who attended the exhibit tested positive for other enteric pathogens, including other types of E coli. Two specimens tested negative.

Of seven environmental samples tested by the SPHL, three were positive for stx2 by PCR but was not isolated by culture. Of these samples, two were swabs taken of the fence enclosing the goat area and one was a swab of the chicken cage. Of 31 environmental samples sent to the USDA Agro ecosystem Management Research Unit, three samples had four£. coli 0157 isolates confirmed by the SPHL. Notably, all four£. coli O157:H7 isolates detected were unrelated to clinical isolates by WGS (365 allele difference) and were negative by PCR for stxl- and stx2- encoding genes. Of these three samples, one was from feces in the sheep area of the exhibit and two were taken from sheep manure.

Discussion and Conclusion

TDH FED program, NERO, andSullivan County Regional HealthDepartments investigated a large STEC outbreak linked to a “farm days” animal exhibit held September 26-27, 2023. Transmission of STEC O157:H7 was linked to this common event and most likely occurred due to contact with animals and the animal environment. The event had been held in previous years and was organized for kindergarten and second grade students at local schools. All laboratory confirmed STEC O157cases occurred in persons who either attended the event or became ill after a family member who attended the event experienced a diarrheal illness, consistent with secondary transmission within households. Laboratory findings indicated a common exposure source with nearly identical WGS results for all human stool STEC O157 isolates.

During the environmental assessment, several factors were observed or described that likely increased risk for STEC O157 transmission. Notably, children had direct animal contact then participated in an artificial cow milking station after which they were given a sealed carton of milk to open and drink. Restrooms and a portable handwashing station were available at the event; however, these were not integrated into the flow of these activities. Supervised handwashing was not required after leaving animal areas. Additionally, cartons of milk can require extensive manipulation to open, potentially contributing to transmission from contaminated hands. Environmental testing and animal testing that was conducted after the event ended provided evidence of STEC, although ultimately the outbreak strain was not identified. The outbreak strain might not have been detected because sampling occurred in areas without the strain, or because animals were no longer shedding the bacteria when tested weeks later.

Five confirmed cases occurred in households due to secondary transmission from family members who attended the “farm days” event. Additionally, another 23 suspect cases were identified among household members experiencing gastrointestinal illnesses. The number of secondary cases highlighted ongoing risk. TDH disseminated information about reducing household risk through actions such as cleaning shoes, disinfecting assistive equipment or strollers, and hand hygiene after attending an animal exhibit.

STEC has a low infectious dose and resides in the gastrointestinal tract of many ruminant farm animals such as cattle, goats, and sheep without causing illness in the animal. STEC outbreaks from animal contact have been well documented in Tennessee, the United States, and globally. Transmission risk has been shown to increase in outbreaks due to direct contact with animals and their environment coupled with inadequate handwashing measures.

In response to this outbreak, TDH and Sullivan County Regional Health Department worked with school officials to notify parents on October 6 and 9. Risk and prevention information was shared about STEC and staying healthy at animal exhibits. TDH NERO and Sullivan County Regional Health Department notified primary care and emergency medicine clinicians during October 6–10 about the outbreak, provided information about STEC, and encouraged stool testing of patients with diarrheal illness. During October 24-26, virtual and in-person meetings were held with event organizers, venue staff, and school districts to provide recommendations for staying healthy at animal exhibits. Recommendations from the Compendiumof Measures to Prevent Disease Associate with Animals in Public Settings by the National Association of State Public Health Veterinarians were disseminated and discussed.

TDH FED, NERO, and Sullivan County Regional Health Department identified a large STEC O157:H7 outbreak following a “farm days” animal exhibit for school children. Epidemiologic, environmental, and laboratory evidence support direct contact with ruminant animals carrying STEC O157:H7 and their environment as the likely cause. This outbreak included notable secondary transmission from infected event attendees to other household members. Measures to reduce risk at the event such as education prior to the event, supervised handwashing, and venue design were limited. Recommendations for future events were shared with event organizers, venue operators, and affected school districts.

Citations

  1. Centers for Disease Control and Prevention. Shiga Toxin-producing Escherichia coli (STEC) 2018 Case Definition. Published June 29, 2021. Accessed November 16, 2023. https://ndc.services.cdc.gov/case-definitions/shiga-toxin-producing-escherichia-coli-2018/
  2. Centers for Disease Control and Prevention. E. coli Infection. Healthy Pets, Healthy People. Published July 8, 2019. Accessed November 16, 2023. https://www.cdc.gov/healthypets/diseases/ecoli.html
  3. Ferraro L. Notes from the Field: An Outbreak of Shiga Toxin–Producing Escherichia coli O157:H7Associated with a Farming Camp — Tennessee, 2022. MMWR Morb Mortal Wkly Rep. 2023;72. doi:10.15585/mmwr.mm7229a6
  4. Centers for Disease Control and Prevention (CDC). Outbreak of Shiga toxin-producing Escherichiacoli O157 infection associated with a day camp petting zoo–Pinellas County, Florida, May-June 2007. MMWR Morb Mortal Wkly Rep. 2009;58(16):426-428.
  5. Food Safety News. Visitors at petting zoo exposed to E.coli. Food Safety News. Published April 27, 2022. Accessed November 16, 2023. https://www.foodsafetynews.com/2022/04/visitors-at-petting-zoo-exposed-to-e-coli/
  6. Laughlin M, Gambino-Shirley K, Gacek P, et al. Outbreak of Escherichia coli O157 Infections Associated with Goat Dairy Farm Visits — Connecticut, 2016. MMWR Morb Mortal Wkly Rep. 2016;65. doi:10.15585/mmwr.mm655051
  7. Nichols MC, Gacek P, Phan Q, et al. Agritourism and Kidding Season: A Large Outbreak of HumanShiga Toxin-Producing Escherichia coli O157 (STEC O157) Infections Linked to a Goat Dairy Farm—Connecticut, 2016. Front Vet Sci. 2021;8:744055. doi:10.3389/fvets.2021.744055
  8. Centers for Disease Control and Prevention. Outbreaks of Escherichia coli O157:H7 Associatedwith Petting Zoos — North Carolina, Florida, and Arizona, 2004 and 2005. MMWR Morbidity and Mortality Weekly Report. 54(50):1277-1280.
  9. Durso LM, Reynolds K, Bauer N, Keen JE. Shiga-toxigenic Escherichia coli O157:H7 infections among livestock exhibitors and visitors at a Texas County Fair. Vector Borne Zoonotic Dis. 2005;5(2):193-201. doi:10.1089/vbz.2005.5.193
  10. Rowell S, King C, Jenkins C, et al. An outbreak of Shiga toxin-producing Escherichia coli serogroupO157 linked to a lamb-feeding event. Epidemiol Infect. 2016;144(12):2494-2500.doi:10.1017/S0950268816001229
  11. Schlager S, Lepuschitz S, Ruppitsch W, et al. Petting zoos as sources of Shiga toxin- producingEscherichia coli (STEC) infections. Int J Med Microbiol. 2018;308(7):927-932. doi:10.1016/j.ijmm.2018.06.008
  12. Centers for Disease Control and Prevention. E. coli (Escherichia coli). E. coli. Published December 1,2022. Accessed November 16, 2023. https://www.cdc.gov/ecoli/index.html
  13. Centers for Disease Control and Prevention. Stay Healthy at Animal Exhibits. Healthy Pets, Healthy People. Published July 13, 2022. Accessed November 16, 2023. https://www.cdc.gov/healthypets/specific-groups/stay-healthy-animal-exhibits.html
  14. Freedman SB, van de Kar NCAJ, Tarr PI. Shiga Toxin–Producing Escherichia coli and the Hemolytic–Uremic Syndrome. New England Journal of Medicine. 2023;389(15):1402-1414. doi:10.1056/NEJMra2108739
  15. Daly RF, Mathewson AA, Pride KR, Ireland MJ, Bailey SJ. Compendium of Measures to PreventDisease Associated with Animals in Public Settings, 2023. Published online 2023. Accessed November 16, 2023. https://www.nasphv.org/Documents/AnimalsInPublicSettings2023.pdf

The Food and Drug Administration has issued a warning about certain mussels from Allen’s Fisheries in Newfoundland, Canada, that were imported to the United States.

On March 1 the New Jersey Department of Health advised the FDA of an outbreak of illness associated with consumption of the mussels. The patients experienced symptoms including nausea, vomiting and diarrhea. 

The advisory includes mussels from Allen’s Fisheries (NL0047SP) in Newfoundland, Canada, harvested on Feb. 7 (Julian date 24038), from harvest area AQ # 15 Newfoundland, with final harvest date of Feb. 18 (Julian date 24049) and shipped to distributors in Connecticut, Florida, Maryland, Massachusetts, New Jersey, New York and Pennsylvania on or around Feb. 21 (Julian Date 24052).

The FDA is advising restaurants and food retailers not to serve or sell and consumers not to eat the implicated mussels because of possible pathogen or biotoxin contamination. The FDA is awaiting further information on distribution of the mussels and will continue to monitor the investigation and provide assistance to state authorities as needed. 

“Contaminated shellfish can cause illness, especially if eaten raw, particularly in people with compromised immune systems. Food contaminated with pathogens or biotoxins may look, smell, and taste normal. Consumers of these products who are experiencing food poisoning symptoms such as diarrhea, stomach pain or cramps, nausea, vomiting or fever should contact their healthcare provider, who should report their symptoms to their local health department,” according to the FDA Warning.

Restaurants and retailers should dispose of any products by throwing them in the garbage or contacting their distributor to arrange for return and destruction.

Restaurants and retailers should also be aware that shellfish may be a source of pathogens and should control the potential for cross-contamination of food processing equipment and the food processing environment. They should follow the steps below:

  • Wash hands with warm water and soap following the cleaning and sanitation process.
  • Retailers, restaurants, and other food service operators who have processed and packaged any potentially contaminated products need to be concerned about cross-contamination of cutting surfaces and utensils through contact with the potentially contaminated products.
  • Retailers that have sold bulk product should clean and sanitize the containers used to hold the product.

What is the problem?

Through product testing, the FDA has determined that the ground cinnamon products listed in the table below contain elevated levels of lead and that prolonged exposure to these products may be unsafe.

The FDA is advising consumers to throw away and not to buy these ground cinnamon products.  The FDA has recommended that the firms voluntarily recall these products, with the exception of the MTCI cinnamon. The FDA has been unable to reach MTCI to share our findings and request that the company initiate a recall. The FDA will update this notice with the communications from firms that voluntarily agree to recall as we receive them.

Products

DistributorRetailersBrand
Names(s)
Lots/CodesLead
Concentration
(ppm)
Product Image
La Fiesta Food Products
La Miranda, CA           
La SuperiorSuperMercadosLa Fiesta250332.73La Fiesta Food Products La Miranda CA - La Superior SuperMercados
Marcum, Moran Foods, LLC
Saint Ann, MO       
Save A Lot   MarcumBest By:10/16/25 10 084/6/25 040081 
(Missouri)
  3.20  2.90Marcum, Moran Foods LLC Saint Ann MO - Save A Lot
MTCI
Santa Fe Springs, CA 
SF SupermarketMKNo codes2.99MTCI Santa Fe Springs CA - SF Supermarket
Raja Foods LLC
Skokie, IL     
Patel Brothers   SwadKX21223 
Best Before: July 2026  
2.12SWAD, Raja Foods LLC Skokie IL - Patel Brothers
Greenbriar International, Inc.
Chesapeake, VA        
Dollar Tree  Family Dollar Supreme
Tradition
Best By:09/29/25 09E804/17/25  04E11 12/19/25 12C204/12/25 04ECB1208/24/25 08A_ _04/21/25 04E504/21/25 04E5 2025-09-22 09E20 2025-09-22 09E20 (Missouri)    3.372.262.032.343.142.883.123.10Supreme Tradition Greenbriar International Inc Chesapeake VA - Dollar Tree
El Chilar
Apopka, FL
La Joya Morelense 
(Baltimore, MD)
El ChilarF275EX1026 (Maryland)D300EX1024 (Maryland) 3.42.93El Chilar - Apopka, FL - La Joya Morelense (Baltimore, MD)

Recommendations for consumers

  • The FDA is advising consumers to stop using and dispose of these products. 
  • Consumers should not eat, sell, or serve ground cinnamon products listed in the table above and should discard them.  
  • These products have a long shelf life. Consumers should check their homes and discard these products.  
  • If there’s suspicion that someone has been exposed to elevated levels of lead, talk to your healthcare provider. Most people have no obvious immediate symptoms of lead exposure. 

Who to Contact

Health care professionals, patients and consumers are encouraged to report complaints and cases of exposure and adverse events to the FDA’s MedWatch Safety Information and Adverse Event Reporting Program.

To report a complaint or adverse event (illness or serious allergic reaction), you can

Purpose 

The FDA is advising consumers to throw away and not to buy the ground cinnamon products listed above because samples of these products were found to contain elevated levels of lead. Based on FDA’s assessment, prolonged exposure to these products may be unsafe and could contribute to elevated levels of lead in the blood. Long-term exposure (months to years) to elevated levels of lead in the diet could contribute to adverse health effects, particularly for the portion of the population that may already have elevated blood lead levels from other exposures to lead. No illnesses or adverse events have been reported to date in association with these products.  

While the ground cinnamon products in this alert may not be a food targeted to young children, cinnamon is used in many foods young children consume. Consistent with the agency’s Closer to Zero initiative, which focuses on reducing childhood exposure to lead, the agency is recommending voluntary recall of the products listed above because prolonged exposure to the products may be unsafe. Removing the ground cinnamon products in this alert from the market will prevent them from contributing elevated amounts of lead to the diets of children.

Summary and Scope of the Problem

Following the October 2023 recall of cinnamon apple puree and applesauce products due to elevated lead levels linked to the cinnamon in those products and the concern for lead toxicity in children, the FDA initiated a targeted survey of ground cinnamon products from discount retail stores and analyzed the samples for lead and chromium.  

Based on results from the survey, the FDA is recommending recalls of ground cinnamon from six distributors whose products had elevated lead levels ranging from 2.03 to 3.4 parts per million (ppm) (see table above for a full list of lead levels in these products). These levels are significantly lower than the levels of lead associated with the ongoing investigation into ground cinnamon from Ecuador supplied by Negasmart to Austrofoods, the manufacturer of the apple puree and applesauce products, which were between 2,270 ppm to 5,110 ppm in the cinnamon.  

In addition to the FDA’s sampling and analysis, some states also analyzed samples of cinnamon through the Laboratory Flexible Funding Model. This is a cooperative agreement with states to help investigate, monitor and remove adulterated foods from commerce and aid regulatory programs. The Maryland and Missouri Departments of Health collected cinnamon samples included in this safety alert. 

FDA Actions

The FDA will continue to work with manufacturers, distributors, and retailers to remove unsafe products from the market, and to further investigate the sources of the lead contamination as appropriate.  

The FDA is also continuing its Toxic Elements monitoring program, which includes testing of a variety of foods including colored spices offered for sale in the U.S. Our sampling at import has prevented some cinnamon with elevated lead levels from entering U.S. commerce; however, like all of our surveillance activities, these monitoring programs only evaluate a subset of the commodity being imported. FDA will follow-up on these findings as well as continue our activities at import to prevent unsafe cinnamon from reaching consumers in the U.S., including by adding firms and products to import alert where appropriate. Ultimately, it is the responsibility of the manufacturers and the importers to ensure the safety of the products that enter into the U.S. market.  

The FDA also sent a letter to all cinnamon manufacturers, processors, distributors, and facility operators in the U.S. reminding them of the requirement to implement controls to prevent contamination from potential chemical hazards in food, including in ground cinnamon products. The FDA will continue to work with firms to ensure they are meeting their responsibilities under provisions of the Current Good Manufacturing Practice, Hazard Analysis, and Risk-Based Preventive Controls for Human Food rule.  

Potential Health Effects  

Based on FDA’s assessment, consuming these products could contribute to elevated levels of lead in the blood. Long-term exposure (months to years) to elevated levels of lead in the diet could contribute to adverse health effects, particularly for the portion of the population that may already have elevated blood lead levels from other exposures to lead. If you are concerned that you or anyone in your family may have symptoms of lead toxicity, the FDA recommends you contact your healthcare provider.     

The potential for adverse health effects from consuming food contaminated with lead vary depending on the level of lead in the food; age of the consumer; length, amount, and frequency of exposure to lead in the food; and other exposures to different sources of lead. For example, the very young are particularly vulnerable to the potential harmful effects from lead exposure because of their smaller body sizes and rapid metabolism and growth. High levels of exposure to lead in utero, infancy, and early childhood can lead to neurological effects such as learning disabilities, behavior difficulties, and lowered IQ.    

FDA’s Advice to Help Protect Against the Effects of Lead 

Good nutrition – like meeting the recommendations in the Dietary Guidelines for Americans – can help protect against the health effects from exposure to lead. Eating a variety of healthy foods can make it less likely for an individual to be exposed to the same contaminant from the same food many times and helps to provide the range of nutrients needed for health and, for children, healthy development. Having adequate nutrients stored in the body also can help to prevent lead from having harmful effects. To get adequate food variety, FDA recommends that consumers eat many different foods from the five food groups – vegetables, fruits, grains, dairy, and protein foods – and to alternate how often you provide the same food.  

Additional Information 

A former raw milk cheese manufacturer and the company he owned and managed pleaded guilty today to charges related to cheese that was linked to a 2016-2017 outbreak of listeriosis, the disease caused by the pathogen Listeria monocytogenes

Johannes Vulto and his company, Vulto Creamery LLC, each pleaded guilty to one misdemeanor count of causing the introduction of adulterated food into interstate commerce. Vulto oversaw operations at Vulto Creamery manufacturing facility in Walton, New York, including those relating to sanitation and environmental monitoring. In pleading guilty, Vulto and Vulto Creamery admitted that between December 2014 and March 2017, they caused the shipment in interstate commerce of adulterated cheese.

According to the plea agreement, environmental swabs taken at the Vulto Creamery facility between approximately July 2014 and February 2017 repeatedly tested positive for Listeria species. The Listeria family includes both harmless species and L. monocytogenes, which can cause listeriosis in humans. In March 2017, after the U.S. Food and Drug Administration (FDA) linked Vulto Creamery’s cheese to an outbreak of listeriosis, Vulto shut down the Vulto Creamery facility and issued a partial recall that was expanded to a full recall within weeks. According to the Centers for Disease Control and Prevention, the listeriosis outbreak resulted in eight hospitalizations and two deaths.

“It is crucial that American consumers be able to trust that the foods they buy are safe to eat,” said Principal Deputy Assistant Attorney General Brian Boynton, head of the Justice Department’s Civil Division. “The department will continue to work with its law enforcement partners to hold responsible food manufacturers that sell dangerously contaminated products.”

“This investigation and prosecution holds accountable the defendant and his business who through unsafe practices caused illness and death to consumers in an entirely preventable tragedy,” said U.S. Attorney Carla B. Freedman for the Northern District of New York. “The law enforcement and regulatory partners involved in this case will continue to work together to bring to justice those who endanger the public through unsafe and unsanitary products and facilities.”

“U.S. consumers rely on the FDA to ensure that their food is safe and wholesome,” said Special Agent in Charge Fernando McMillan of FDA’s Office of Criminal Investigations New York Field Office. “When companies and individuals put themselves above the law by producing food that endangers and harms the public, as occurred in this case, we will see that they are brought to justice.” 

Listeriosis is a severe, invasive illness that can be life-threatening in some cases. Persons who have the greatest risk of experiencing listeriosis due to consumption of foods contaminated with L. monocytogenes are pregnant women and their newborns, the elderly and persons with weakened immune systems.

Vulto and Vulto Creamery pleaded guilty before Magistrate Judge Thérèse Wiley Dancks in Syracuse, New York. A sentencing date will be set by the court. Further information about the case will be posted under “Information for Victims in Large Cases” at the Consumer Protection Branch’s website: www.justice.gov/civil/consumer-protection-branch.

The FDA’s Office of Criminal Investigations investigated the case.

Senior Trial Attorney James T. Nelson of the Civil Division’s Consumer Protection Branch and Assistant U.S. Attorney Michael F. Perry for the Northern District of New York prosecuted the case.

For more information about the enforcement efforts of the Consumer Protection Branch, visit www.justice.gov/civil/consumer-protection-branch.

Here are the details of the outbreak:

Case Count: 8 – Connecticut (1), Florida (1), New York (5) and Vermont (1)

CDC collaborated with public health and regulatory officials in several states and the U.S. Food and Drug Administration (FDA) to investigate a multistate outbreak of Listeria monocytogenes infections (listeriosis). Listeria causes a serious, life-threatening illness.

Listeria specimens from ill people were collected from September 1, 2016 to March 13, 2017. Ill people ranged in age from less than one year to 89 years, with a median age of 52 years. Five of eight ill people were female. All eight (100%) ill people were hospitalized, including two people from Connecticut and Vermont who died. One of the illnesses was reported in a newborn.

Epidemiologic and laboratory evidence indicated that soft raw milk cheese made by Vulto Creamery of Walton, New York, was the likely source of this outbreak.

State and local health departments interviewed ill people or their family members about the foods they ate or other exposures in the month before their illness started. Based on those interviews, eight (100%) of eight people ate a soft cheese. The ill resident of Florida reported traveling to New York state and eating soft cheese there before becoming ill. Available information indicated that cheese made by Vulto Creamery was for sale at stores where at least seven of the ill people bought cheese before getting sick.

The Connecticut Department of Public Health collected leftover cheeses from the home of the deceased person in Connecticut. The outbreak strain of Listeria was identified in a leftover cheese that the family identified as Ouleout cheese from Vulto Creamery.

The New York Division of Milk Control and Dairy Services collected three intact wheels of Ouleout cheese from Vulto Creamery. The outbreak strain of Listeria was identified in samples taken from the three wheels of cheese. On March 7, 2017, Vulto Creamery recalled all lots of Ouleout, Miranda, Heinennellie, and Willowemoc soft wash-rind raw milk cheeses. On March 10, the company expanded the recall to include four other cheeses: Andes, Blue Blais, Hamden, and Walton Umber. The raw milk cheeses were distributed nationwide, with most sold in stores in the northeastern and Mid-Atlantic states; California; Chicago; Portland, Oregon; and Washington, D.C.

The Alameda County Public Health Department, Los Angeles Department of Public Health, and California Department of Public Health (CDPH) investigated an outbreak of shigellosis associated with a Kaiser Permanente union delegate conference held at the Westin Bonaventure Hotel in downtown Los Angeles from August 21 to August 24, 2023. The event included 269 attendees from across California. This outbreak was assigned the code “OB20233135.”

A total of 32 cases were identified linked to this outbreak. Ages ranged from 41 to 71 years (median 49.5). Seventy-two percent of cases with known information were female. Known illness onset dates ranged from August 24 to August 26, 2023. Four cases were hospitalized, and no deaths were reported.

All but seven of the known cases were at least PCR positive for Shigella. At least 13 of the known cases were positive for Shigella flexneri, type 3. Whole genome sequencing determined that five of these cases were infected with near identical Shigella strains (within 0-1 alleles).

The Los Angeles Department of Public Health distributed a REDCap survey to all conference attendees to collect exposure information. A total of 85 survey responses were recorded as of September 8. The boxed lunch served on August 24, 2023 was the primary exposure of interest.The main kitchen at the Westin Bonaventure was investigated by Los Angeles County Environmental Health. The main kitchen was closed on September 1, 2023. At least one ill worker was identified with an onset of August 25, 2023. One other employee had left work early on an undetermined day. Thirteen out of 14 employees were tested: one asymptomatic employee was positive for Shigella/EIEC, EPEC who had also prepared the chicken curry and tuna salad wrap. One other asymptomatic employee was positive for STEC and did not participate in making the wrap. 

An outbreak of Salmonella was investigated by the Illinois Department of Public Health (IDPH) and the Chicago Department of Public Health (CDPH) in the summer of 2023. This outbreak was assigned the outbreak code IL2023-1678. An increase in the number of Salmonella cases was identified in September 2023, and the only location found to be common to these early cases was Carniceria Guanajuato at 3140 N. California Ave. in Chicago, Illinois, a grocery store chain and taqueria. Only this location was linked to the outbreak.

On September 8, CDPH issued a health alert to all Chicago hospitals to notify them of the outbreak, request prompt reporting of Salmonella cases, and inform clinicians of the high hospitalization rate among cases. On September 14, 2023, CDPH shared a press release about the outbreak to encourage all persons who dined at Carniceria Guanajuato to report their exposure to CDPH and to seek testing with their provider if they were experiencing symptoms. IDPH issued a CD alert to local health departments to notify them of any Salmonella cases who reported eating food purchased from Carniceria Guanajuato to interview or contact CDPH.

Outbreak definitions were created. A confirmed case was considered an individual who tested positive for S. Newport that was highly related (within 10 alleles) to the outbreak strain by whole genome sequencing (WGS) from August to September 2023, or a patron who reported eating at Carniceria Guanajuato in the week prior to onset of symptoms and tested positive via a culture for Salmonella at a clinical laboratory. A probable case (with lab testing) was defined as a patron who reported eating at Carniceria Guanajuato in the week prior to onset of symptoms and tested positive via a non-culture test for Salmonella at a clinical laboratory. A probable case (ill meal companion) was defined as a patron who had diarrhea (>3 stools in a 24-hour period) and/or vomiting and reported eating at Carniceria Guanajuato in the week prior to onset of symptoms and was epi-linked to a confirmed case. A probable case (clinically compatible illness with known exposure) was defined as a patron who had diarrhea (>3 stools in a 24-hour period) that was at least three days in duration or was accompanied by fever and reported eating at Carniceria Guanajuato in the week prior to onset of symptoms and was not epi-linked to a confirmed case.

            A total of 109 (45 confirmed, 64 probable) cases who met the outbreak definition were reported in this outbreak. Seven confirmed cases denied or could not recall eating at Carniceria Guanajuato despite matching the outbreak WGS pattern, and thus were excluded from the statistical analysis. One case was a resident of Louisiana. Median age of all cases was 36 years (range, 6 to 70 years); 62 (61%) were male.  For whom information was collected, 25 (23%) were hospitalized. For whom information was collected, none died. Exposures were reported between August 27 and September 6, 2023. Onsets were reported between August 27 and September 13, 2023. Most cases experienced diarrhea (some bloody), fever, and vomiting.

A case-control study was conducted to determine a potential food vehicle for infection with Salmonella. To identify controls, CD Program staff asked confirmed cases about their meal companions and obtained a list of individuals who placed orders through the online delivery service Uber Eats and consumed food between August 27 to September 8, 2023. The case-control analysis included 38 confirmed cases and 30 controls. Based on case exposure information collected for a case-control study, environmental and food testing, and a facility inspection, the common location to cases was Carniceria Guanajuato at 3140 N. California Ave. in Chicago, Illinois. 

A statistically significant association was observed between multiple food items and illness, including consumption of lettuce (odds ratio [OR] 5.96, 95% CI: 2.07-17.19), tomato (OR 5.96, 95% CI: 2.07-17.19), beans (OR 7.12, 95% CI: 2.40-21.13), and steak torta (OR 5.85, 95% CI: 1.71-20.02). These items are standard toppings included on a torta, and thus were highly correlated with one another. Lettuce, tomato and beans were all consumed by 68% of confirmed cases. Consumption was variable, however, among probable cases with lettuce, tomato and beans being consumed by 77%, 58% and 56% of probable cases respectively. 

On September 8, 2023, the Food Protection Division (FPD) conducted an environmental inspection of Carniceria Guanajuato and collected the following: food samples, initial information about restaurant employees and food preparation, and copies of invoices for food items. Food items collected included steak (raw and cooked), lettuce, onion, cilantro, tomato, avocado, refried beans, chile relleno, guacamole, pico de gallo, chile de arbol, and red salsa. CD Program staff performed in-depth interviews with the owners of the restaurant and employees. Because employees functioned in multiple roles, 14 restaurant employees were considered food handlers for the purposes of this outbreak investigation. Food handlers were asked to submit stool specimens to screen for Salmonella. Among the 14 food handlers interviewed, none reported any history of gastrointestinal illness in the two weeks preceding or during the outbreak period.

Several violations were identified during the sanitarians’ inspection of Carniceria Guanajuato: raw beef steak was observed above ready to eat foods (e.g., sliced lettuce) inside prep cooler, two cutting boards with deep seams and stains in found in the prep/cooking area, sliced tomatoes were held at an improper temperature, and improper cleaning of large pots due to the inability to submerge the pots in the sinks. Carniceria Guanajuato voluntarily closed on September 8, 2023 and re-opened on September 22, 2023. No additional complaints were received in association with the restaurant in the month following the date of this incident.

The outbreak strain was identified as Salmonella Newport. Specimens from the 38 confirmed cases included in the analysis yielded Salmonella isolates. Thirty-seven of the isolates were S. Newport and were clustered within 0-2 single-nucleotide polymorphisms (SNP) differences, indicating a close link among the cases. A second serotype was identified among one of the confirmed cases as a Multi-Drug Resistant strain of S. Newport. Additionally, of the 14 food handlers were screened, four tested positive for the outbreak strain of S. Newport and one tested positive for a different serotype, S. Enteritidis. Red salsa collected on September 8 from the grocery store cooler was found to be positive for S. Johannesburg, which was different than the outbreak strain of S. Newport. None of the other tested foods were found to be positive for Salmonella.

Statistical analysis with only confirmed cases identified beans as being statistically significant. This, however, did not align with the results of the sensitivity analysis, which used both confirmed and probable cases and found lettuce to be statistically significant. This misalignment is likely due to both differences in consumption of food items by confirmed versus probable cases and methodological limitations (i.e., unmatched case-control, insufficient number of controls) of the study. CDPH hypothesized that lettuce was the likely source of this outbreak, as it is fresh produce and is consequently at higher risk of contamination. This outbreak may have been caused by contamination of lettuce by infected food handlers or through cross-contamination from another source. The presence of multiple serotypes identified among cases, food handlers, and prepared foods also suggests the possibility of multiple cross-contamination events. Closure of the restaurant during the early stage of the investigation prevented additional cases of illness from occurring.