185 sick: Cyclosporiasis in Del Monte veggie trays

As of June 28, 2018 (11am EDT), the U.S Centers for Disease Control (CDC) has been notified of 185 laboratory-confirmed cases of cyclosporiasis in persons who reportedly consumed pre-packaged Del Monte Fresh Produce vegetable trays containing broccoli, cauliflower, carrots, and dill dip. The reports have come from four states.

Seven (7) of these people have been hospitalized, and no deaths have been reported.

  • Epidemiologic evidenceindicates that pre-packaged Del Monte Fresh Produce vegetable trays containing broccoli, cauliflower, carrots, and dill dip are the likely source of these infections.
    • Most ill people reported eating pre-packaged Del Monte Fresh Produce vegetable trays containing broccoli, cauliflower, carrots, and dill dip.
    • Most ill people reported buying pre-packaged Del Monte Fresh Produce vegetable trays containing broccoli, cauliflower, carrots, and dill dip in the Midwest. Most people reported buying the trays at Kwik Trip convenience stores.
    • The investigation is ongoing. CDC will provide updates when more information is available.

The median illness onset date among patients is May 31, 2018 (range: May 14 to June 9).  Ill people range in age from 13 to 79 years old, with a median age of 47. Fifty-seven percent (57%) are female and 7 people have been hospitalized. No deaths have been reported.

Illnesses that began after May 17, 2018 might not have been reported yet due to the time it takes between when a person becomes ill and when the illness is reported.

Beware the canal waters (I’m looking at you Holland Marsh, Ontario, that’s in Canada): Canal irrigation water likely source of E. coli O157 outbreak linked to romaine lettuce 5 dead, 218 sick

The U.S. Food and Drug Administration, along with the Centers for Disease Control and Prevention (CDC) and state and local partners, are investigating a multistate outbreak of E. coli O157:H7 illnesses linked to romaine lettuce from the Yuma, Arizona, growing region.

The FDA, along with CDC and state partners, initiated an environmental assessment in the Yuma growing region to further investigate potential sources of contamination linked to this outbreak.

Samples have been collected from environmental sources in the region, including water, soil, and cow manure. Evaluation of these samples is ongoing.

To date, CDC analysis of samples taken from canal water in the region has identified the presence of E. coli O157:H7 with the same genetic finger print as the outbreak strain. We have identified additional strains of Shiga-toxin producing E. coli in water and soil samples, but at this time, the samples from the canal water are the only matches to the outbreak strain.

Analysis of additional samples is still ongoing, and any new matches to the outbreak strain will be communicated publicly and with industry in the region.

Identification of the outbreak strain in the environment should prove valuable in our analysis of potential routes of contamination, and we are continuing our investigation in an effort to learn more about how the outbreak strain could have entered the water and ways that this water could have come into contact with and contaminated romaine lettuce in the region.

As of June 27, the CDC reports that 218 people in 36 states and Canada have become ill. These people reported becoming ill in the time period of March 13, 2018 to June 6, 2018. There have been 96 hospitalizations and five deaths.

The traceback investigation indicates that the illnesses associated with this outbreak cannot be explained by a single grower, harvester, processor, or distributor. While traceback continues, the FDA will focus on trying to identify factors that contributed to contamination of romaine across multiple supply chains.  The agency is examining all possibilities, including that contamination may have occurred at any point along the growing, harvesting, packaging, and distribution chain before reaching consumers. 

The FDA, along with CDC and state partners, initiated an environmental assessment in the Yuma growing region to further investigate potential sources of contamination linked to this outbreak. To date, CDC analysis of samples taken from canal water in the region has identified the presence of E. coli O157:H7 with the same genetic finger print as the outbreak strain. We have identified additional strains of E. coli in water and soil samples, but at this time, the samples from the canal water are the only matches to the outbreak strain.

The FDA is continuing to investigate this outbreak and will share more information as it becomes available.

“More work needs to be done to determine just how and why this strain of E. coli O157:H7 could have gotten into this body of water and how that led to contamination of romaine lettuce from multiple farms,” said Dr. Scott Gottlieb, commissioner of the U.S. Food and Drug Administration, in a statement.

How produce gets contaminated in the field: A review

Foodborne illness resulting from the consumption of contaminated fresh produce is a common phenomenon and has severe effects on human health together with severe economic and social impacts.

The implications of foodborne diseases associated with fresh produce have urged research into the numerous ways and mechanisms through which pathogens may gain access to produce, thereby compromising microbiological safety.

This review provides a background on the various sources and pathways through which pathogenic bacteria contaminate fresh produce; the survival and proliferation of pathogens on fresh produce while growing and potential methods to reduce microbial contamination before harvest.

Some of the established bacterial contamination sources include contaminated manure, irrigation water, soil, livestock/ wildlife, and numerous factors influence the incidence, fate, transport, survival and proliferation of pathogens in the wide variety of sources where they are found. Once pathogenic bacteria have been introduced into the growing environment, they can colonize and persist on fresh produce using a variety of mechanisms.

Overall, microbiological hazards are significant; therefore, ways to reduce sources of contamination and a deeper understanding of pathogen survival and growth on fresh produce in the field are required to reduce risk to human health and the associated economic consequences.

 

Sources and contamination routes of microbial pathogens to fresh produce during field cultivation: A review

Food Microbiology, vol. 73, pg. 177-208

Oluwadara Alegbeleye, Ian Singleton and Anderson Sant’Ana

https://doi.org/10.1016/j.fm.2018.01.003

https://www.sciencedirect.com/science/article/pii/S0740002017310158?via%3Dihub

PMA: Research on produce safety priorities

Bob Whitaker, Ph.D., chief science and technology officer for Produce Marketing Association (PMA), writes that because it provides inherently healthy, nutritious foods, the fresh produce industry is uniquely positioned to help solve the nation’s obesity epidemic. To do so, consumers must have confidence in the safety of the fresh fruits, vegetables, and nuts they eat and feed their families.

A green row celery field is watered and sprayed by irrigation equipment in the Salinas Valley, California USA

Following a large and deadly outbreak of foodborne illness linked to fresh spinach in 2006, the U.S. produce industry couldn’t wait for government or other direction. After finding significant knowledge gaps and a lack of data needed to build risk- and science-based produce safety programs, the industry created the Center for Produce Safety (CPS) in 2007.

CPS works to identify produce safety hazards, then funds research that develops that data as well as potential science-based solutions that the produce supply chain can use to manage those hazards. While two foodborne illness outbreaks in the first half of 2018 associated with leafy greens demonstrate the industry still has challenges to meet, CPS has grown into a unique public-private partnership that moves most of the research it funds from concept to real-world answers in about a year.

Each June, CPS hosts a symposium to report its latest research results to industry, policy makers, regulators, academia, and other produce safety stakeholders. Key learnings from the 2017 symposium have just been released on topics including water quality, cross-contamination, and prevention. A few highlights from those key learnings are summarized here, and for the full details, you can download the Key Learnings report from CPS’s website.

Know Your Water (we were doing that in 2002, long before youtube existed)
Irrigation water is a potentially significant contamination hazard for fresh produce while it is still in the field. While CPS research has revealed many learnings about agricultural water safety in its 10 years, many questions still remain. Meanwhile, the U.S. Food and Drug Administration (FDA)’s proposed Food Safety Modernization Act (FSMA) water testing requirements—which offers some challenges for producers in specific production regions—recently raised even more questions.

New CPS research illustrates the risks of irrigating with “tail water” from runoff collection ponds. With water becoming a precious resource in drought-stricken areas, the objective was to learn if tail water might be recovered and used for irrigation.  We learned that differences among pond sites—for example, water sources, climate, ag management practices—can strongly influence the chemistry and microbiology of the water. Further, water pH can influence disinfection treatment strategies.[1]

CPS research continues to investigate tools for irrigation water testing, looking specifically at sample volumes,[2] and searching for better water quality indicators and indexing organisms including harnessing next-generation DNA sequencing.[3] Following a CPS-organized colloquium on ag water testing in late 2017, FDA subsequently announced it would revisit FSMA’s ag water requirements, and postponed compliance.

Bottom line, CPS research demonstrates that growers must thoroughly understand their irrigation water before they can accurately assess cross-contamination risk. CPS’s findings clearly point to the need to take a systems approach, to understand and control the entire water system to help achieve produce safety. Long term, this may mean prioritizing research into ag water disinfection systems to better manage contamination hazards that can also operate at rates needed for field production.
Cross-Contamination Can Happen across the Supply Chain
While conceptually and anecdotally the fresh produce industry knows that food safety is a supply chain responsibility, research is needed that documents the role of the entire supply chain to keep fresh produce clean and safe from field to fork. At the 2017 CPS Research Symposium, research reports were presented focusing on cross-contamination risks from the packinghouse to retail store display.

In the packinghouse, CPS-funded research found that wash systems can effectively control cross-contamination on fruit, when proper system practices are implemented.[4] Post-wash, CPS research involving fresh-cut mangos also demonstrated that maintaining the cold chain is critical to controlling pathogen populations.[5] Across the cantaloupe supply chain, CPS studies show food contact surfaces—for example, foam padding—are potential points of cross-contamination.[6] See the full 2017 Key Learnings report for details, as these brief descriptions only scratch the surface of this research.

CPS studies clearly demonstrate that food safety is a supply chain responsibility—a message that must be internalized from growers and packers to transporters, storages, and retailers to commercial, institutional, and home kitchens. While translating this research into reality will present engineering and operational challenges, our new understanding of produce safety demands it.
Verifying Preventive Controls
The produce industry must know that its preventive controls are in fact effective. That said, validation can be tricky. If validation research doesn’t mimic the real world, industry ends up fooling itself about whether its food safety processes work—and the human consequences are real.

Numerous scientists presented research at the 2017 CPS Research Symposium that validates various preventive controls, from heat treating poultry litter[7] to pasteurizing pistachios[8] to validating chlorine levels in wash water systems.[9] Some researchers effectively used nonpathogenic bacteria as a surrogate in their validation studies, while another is working to develop an avirulent salmonella surrogate, and another. Wang used actual Escherichia coliO157:H7 (albeit in a laboratory).

Importantly, CPS research finds that the physiological state of a pathogen or surrogate, and pathogen growth conditions themselves, are critically important to validation studies.[10] Meanwhile, suitable surrogates have been identified for some applications, the search continues for many others.

The research findings described here are just some of the real world-applicable results to emerge from CPS’s research program. To learn more, download the 2017 and other annual Key Learnings reports from the CPS website > Resources > Key Learnings page at www.centerforproducesafety.org.

We were doing these videos in the early 2000s, long before youtube.com existed, and weren’t quite sure what to do with them. But we had fun.

 

Bugs be passed around on leafy greens

Several outbreaks of foodborne illness traced to leafy greens and culinary herbs have been hypothesized to involve cross-contamination during washing and processing. This study aimed to assess the redistribution of Salmonella Typhimurium LT2 during pilot-scale production of baby spinach and cilantro and redistribution of Escherichia coli O157:H7 during pilot-scale production of romaine lettuce.

Four inoculated surrogate: uninoculated product weight ratios (10:100, 5:100, 1:100, and 0.5:100) and three inoculation levels (103, 101, and 10−1 CFU/g) were used for the three commodities. For each of three trials per condition, 5-kg batches containing uninoculated product and spot-inoculated surrogate products at each ratio and inoculation level were washed for 90 s in a 3.6-m-long flume tank through which 890 L of sanitizer-free, filtered tap water was circulated. After washing and removing the inoculated surrogate products, washed product (∼23, 225-g samples per trial) was analyzed for presence or absence of Salmonella Typhimurium or E. coli O157:H7 by using the GeneQuence Assay.

For baby spinach, cilantro, and romaine lettuce, no significant differences (P > 0.05) in the percentage of positive samples were observed at the same inoculation level and inoculated: uninoculated weight ratio. For each pathogen product evaluated (triplicate trials), inoculation level had a significant impact on the percentage of positive samples after processing, with the percentage of positive samples decreasing, as the initial surrogate inoculation level decreased.

The weight ratio of contaminated: noncontaminated product plays an important role: positive samples ranged from 0% to 11.6% ± 2.05% and from 68.1% ± 33.6% to 100% among the four ratios at inoculation of 10−1 and 101 CFU/g, respectively.

To our knowledge, this study is the first to assess the redistribution of low levels of pathogens from incoming product to leafy greens during processing and should provide important data for microbial risk assessments and other types of food safety analyses related to fresh-cut leafy greens.

Transfer and redistribution of Salmonella typhimurium LT2 and Escherichia coli O157:H7 during pilot-scale processing of baby spinach, cilantro, and romaine lettuce

Journal of food Protection vol.81 no. 6 June 2018

HALEY S. SMOLINSKI,1 SIYI WANG,1 LIN REN,1 YUHUAN CHEN,2 BARBARA KOWALCYK,3 ELLEN THOMAS,3 JANE VAN DOREN,2 and ELLIOT T. RYSER1*

https://doi.org/10.4315/0362-028X.JFP-17-420

http://jfoodprotection.org/doi/abs/10.4315/0362-028X.JFP-17-420

Money talks: Safety interventions in Dutch vegetable production

Surveys still suck, but the results of this one generally correlate to what we have found doing 20 years of on-farm food safety with fresh produce growers.

Outbreaks and crisis drive grower food safety concerns, prevention is a hard sell, but we’ve shown it can be done.

Understanding growers’ preferences regarding interventions to improve the microbiological safety of their produce could help to design more effective strategies for the adoption of such food safety measures by growers.

The objective of this survey study was to obtain insights for the design of interventions that could stimulate growers to increase the frequency of irrigation water sampling and water testing to reduce possible microbiological contamination of their fresh produce.

The results showed that price intervention, referring to making the intervention less costly by reducing the price via discounts, is the most effective strategy to change growers’ intentions to increase their frequency of irrigation water testing. Moreover, a sense of urgency affects their intentions to increase the frequency of irrigation water testing.

The findings of this survey support the hypothesis that, to date, safety is not perceived as a quality control issue under normal circumstances, but safety becomes an overriding attribute in a food crisis.

Understanding preferences for interventions to reduce microbiological contamination in Dutch vegetable production

June 2018, Journal of Food Protection vol. 81 no. 6

A. P. M. VAN ASSELDONK,1*L. MALAGUTI,2M. L. H. BREUKERS,1 and H. J. van der FELS-KLERX2,3

https://doi.org/10.4315/0362-028X.JFP-17-106

http://jfoodprotection.org/doi/abs/10.4315/0362-028X.JFP-17-106

Does chlorine make pathogens harder to detect in fresh produce?

The microbiological safety of fresh produce is monitored almost exclusively by culture-based detection methods. However, bacterial foodborne pathogens are known to enter a viable-but-nonculturable (VBNC) state in response to environmental stresses such as chlorine, which is commonly used for fresh produce decontamination.

Here, complete VBNC induction of green fluorescent protein-tagged Listeria monocytogenes and Salmonella enterica serovar Thompson was achieved by exposure to 12 and 3 ppm chlorine, respectively. The pathogens were subjected to chlorine washing following incubation on spinach leaves. Culture data revealed that total viable L. monocytogenes and Salmonella Thompson populations became VBNC by 50 and 100 ppm chlorine, respectively, while enumeration by direct viable counting found that chlorine caused a <1-log reduction in viability. The pathogenicity of chlorine-induced VBNC L. monocytogenes and Salmonella Thompson was assessed by using Caenorhabditis elegans. Ingestion of VBNC pathogens by C. elegans resulted in a significant life span reduction (P = 0.0064 and P < 0.0001), and no significant difference between the life span reductions caused by the VBNC and culturable L. monocytogenes treatments was observed. L. monocytogenes was visualized beyond the nematode intestinal lumen, indicating resuscitation and cell invasion. These data emphasize the risk that VBNC food-borne pathogens could pose to public health should they continue to go undetected.

IMPORTANCE Many bacteria are known to enter a viable-but-nonculturable (VBNC) state in response to environmental stresses. VBNC cells cannot be detected by standard laboratory culture techniques, presenting a problem for the food industry, which uses these techniques to detect pathogen contaminants. This study found that chlorine, a sanitizer commonly used for fresh produce, induces a VBNC state in the foodborne pathogens Listeria monocytogenes and Salmonella enterica. It was also found that chlorine is ineffective at killing total populations of the pathogens. A life span reduction was observed in Caenorhabditis elegans that ingested these VBNC pathogens, with VBNC L. monocytogenes as infectious as its culturable counterpart. These data show that VBNC foodborne pathogens can both be generated and avoid detection by industrial practices while potentially retaining the ability to cause disease.

Viable-but-nonculturable listeria monocytogenes and Salmonella enterica serovar Thompson induced by chlorine stress remain infectious

17 April 2018

American Society for Microbiology, vol. 9 no. 2

Callum J. HighmoreaJennifer C. Warnera*Steve D. Rothwellb, Sandra A. Wilksa, C. William Keevila

doi: 10.1128/mBio.00540-18

http://mbio.asm.org/content/9/2/e00540-18

The produce problem: Ingredient analysis at restaurants in Cyclospora outbreaks

By Sept. 2017, the U.S. Centers for Disease Control reported that almost 1,000 people had laboratory-confirmed cases of cyclosporiasis for the year.

Another banner year for the parasite famously associated with Guatemalan raspberries in 1996.

During July 21–August 8, 2017, the Texas Department of State Health Services (DSHS) was notified of 20 cases of cyclosporiasis among persons who dined at a Mediterranean-style restaurant chain (chain A) in the Houston area. On August 10, 2017, DSHS requested assistance from CDC to support ongoing investigations by the City of Houston Health Department, Harris County Public Health, Fort Bend County Health and Human Services, and Brazoria County Health Department. The objectives of this investigation were to determine the source of the illnesses in the Houston area and to generate hypotheses about the source of the national increase in cyclosporiasis in 2017.

Chain A has four locations in the Houston area and a central kitchen where many dishes are prepared. A case-control study was performed using a menu-specific questionnaire focusing on items containing fresh produce. A confirmed case was defined as laboratory-confirmed Cyclospora infection and clinically compatible illness in a person who ate at any location of chain A during May 28–July 15, 2017. A probable case was defined as diarrhea and at least one additional sign or symptom compatible with cyclosporiasis (e.g., anorexia, abdominal cramping, bloating, myalgia, fatigue, vomiting, or low-grade fever) in a person within 2 weeks after dining at chain A during May 28–July 15, 2017. Controls were identified as either dining companions of case-patients who had no illness or patrons who dined at the same chain A location within 2 days of a case-patient visit and who had no illness. For controls identified by the latter method, contact information was obtained using commercially available databases used by local health agencies in Texas. Three controls per case-patient were recruited.

A total of 22 case-patients (16 confirmed and six probable) and 66 controls were enrolled in the study. Case-patients had a median age of 52 years (range = 29–79 years); 50% were female. Analysis compared menu items consumed by case-patients and controls, followed by ingredient-level analysis. The following ingredients were identified as being significantly associated with illness: green onions (matched odds ratio = 11.3; 95% confidence interval = 2.55–104.68), tomatoes (5.5; 1.2–51.7), red onions (4.7; 1.3–21.0), and cabbage (4.0; 1.1–15.9). When analysis was limited to the 16 confirmed case-patients and their corresponding 48 controls, only green onions remained significantly associated with illness (17.6; 2.5–775.7). Restaurant invoices from chain A were collected for all items identified during the epidemiologic investigation, but efforts to trace any food item to its source were inconclusive. Although the current study identified potential foods associated with illness in Texas, investigators were not able to identify the illness source or confirm whether the patients within the chain A subcluster had consumed a product reported by other ill persons in the United States.

Cyclosporiasis is an intestinal illness caused by the parasite Cyclospora cayetanensis. Since 2013, the United States has experienced annual increases in the incidence of cyclosporiasis incidence during the summer months, with some illnesses linked to imported produce (1–3). Molecular subtyping of Cyclospora is not currently available; therefore, identification of an ingredient associated with a particular illness subcluster might provide information about a source contributing to other cyclosporiasis illnesses. Previous U.S. outbreaks of cyclosporiasis have been linked to fresh produce, such as prepackaged salad mix, raspberries, and cilantro (3,4). Identification of a vehicle for Cyclospora is complicated by the short shelf life of fresh produce as well as the use of potential vehicles such as garnishes or mixtures with other items that could also harbor the parasite. Ingredient-level analysis within restaurant clusters and subclusters therefore remains critical in Cyclospora outbreak investigations.

Notes from the field: Cyclosporiasis cases associated with dining at a Mediterranean-style restaurant chain- Texas 2017

1.jun.18 CDC

Amelia A. Keaton, MD1,2; Noemi Borsay Hall, PhD2,3; Rebecca J. Chancey, MD2,4; Vivienne Heines, MPH3; Venessa Cantu, MPH3; Varsha Vakil, MPH5; Stephen Long, MD5; Kirstin Short, MPH5; Elya Franciscus, MPH6; Natasha Wahab, MPH6; Aisha Haynie, MD6; Laura Gieraltowski, PhD2; Anne Straily, DVM4

https://www.cdc.gov/mmwr/volumes/67/wr/mm6721a5.htm

5 dead, 197 sick from E. coli O157 linked to romaine lettuce

The U.S. Centers for Disease Control reports there are now five people dead and 197 sick from E. coli O157:H7 linked to romaine lettuce.

  • 197 people infected with the outbreak strain of E. coli O157:H7 have been reported from 35 states.
  • 89 people (48%) have been hospitalized, including 26 people who have developed hemolytic uremic syndrome.
  • 5 deaths have been reported from Arkansas (1), California (1), Minnesota (2), and New York (1).
  • Illnesses started on dates ranging from March 13, 2018 to May 12, 2018.
  • Ill people range in age from 1 to 88 years, with a median age of 29.
  • Sixty-eight percent of ill people are female.

The Public Health Agency of Canada has identified people in several Canadian provinces infected with the same DNA fingerprint of E. coli O157:H7.

It takes two to three weeks between when a person becomes ill with E. coli and when the illness is reported to CDC. Most of the people who recently became ill ate romaine lettuce when lettuce from the Yuma, Arizona, growing region was likely still available in stores, restaurants, or in peoples’ homes. Some people who became sick did not report eating romaine lettuce, but had close contact with someone else who got sick from eating romaine lettuce.

According to the U.S. Food and Drug Administration, the last shipments of romaine lettuce from the Yuma growing region were harvested on April 16, 2018, and the harvest season is over. It is unlikely that any romaine lettuce from the Yuma growing region is still available in people’s homes, stores, or restaurants due to its 21-day shelf life.

The traceback investigation indicates that the illnesses associated with this outbreak cannot be explained by a single grower, harvester, processor, or distributor. While traceback continues, the FDA will focus on trying to identify factors that contributed to contamination of romaine across multiple supply chains.  The agency is examining all possibilities, including that contamination may have occurred at any point along the growing, harvesting, packaging, and distribution chain before reaching consumers. 

The FDA has identified Harrison Farms of Yuma, Arizona, as the grower and sole source of the whole-head romaine lettuce that sickened several people in an Alaskan correctional facility, but has not determined where in the supply chain the contamination occurred.

On May 31, 2018 the FDA released a blog with updated information on the traceback investigation (for additional information, visit FDA Update on Traceback Related to the E. coli O157:H7 Outbreak Linked to Romaine Lettuce).

A listing of 78 outbreaks linked to leafy greens since 1995 is posted here.

121 sick, 52 hospitalized, 14 with kidney failure and 1 death linked to Yuma romaine E. coli outbreak

I’m not sure in what universe, the-growing-area-has-stopped-harvesting is a useful explanation for an outbreak of foodborne illness that has sickened 121 and hospitalized almost 50 per cent.

And this picture from 12 years ago is still apt.

I’ll write a much more scathing indictment of the 10-year-experiment in self-fellatio practiced by the Leafy Greens Marketing Association in my upcoming book, Food Safety Fairy Tales.

For now, let it be known that according to the U.S. Centers for Disease Control, E. coli O157:H7 linked to romaine lettuce has sickened 121 people in 25 states.

52 people have been hospitalized, including 14 people who have developed hemolytic uremic syndrome.

One death was reported from California.

This investigation is ongoing, and CDC will provide updates when more information is available.