Leafy greens cone of silence; 33 sickened: environmental investigation of an Escherichia coli O157:H7 outbreak in Oct. 2013 associated with pre-packaged salads

California Department of Public Health (CDPH), Food and Drug Branch (FDB), Emergency Response Unit (ERU) investigated a multi-state foodborne illness outbreak of Escherichia coli O157:H7 (PulseNet Cluster ID 1310CAEXH-1) linked to the consumption of pre-packaged salads purchased in October 2013 at multiple retail locations. The outbreak included a total of 33 ill persons in 4 states; Arizona (1), California (28), Texas (1), and Washington (3). The illness onset dates ranged from October 5, 2013 to November 1, 2013. The case patients had a single matching strain of E. coli O157:H7 (XbaI EXHX01.0589 and BlnI EXHA26.3182).

lettuce.skull.e.coli.O145Initially, two varieties of Trader Joe’s salads were suspected food vehicles in this outbreak. These Trader Joe’s salads were produced by the same manufacturer, Atherstone Foods Inc. in Richmond, CA. As the epidemiological investigation progressed, two additional salads were identified as possibly causing illness.

One of these salads was manufactured by in Oakland, CA, while the other salad was also manufactured by Atherstone Foods Inc., for the Walgreens chain of drug stores. Analysis of the common ingredients among all four salads revealed that romaine lettuce was the only common component. FDB narrowed the traceback to romaine lettuce and determined that a single field of romaine lettuce in Modesto, CA, grown by Ratto Bros. could have been used in the production of all four salads. FDB and the United States Food and Drug Administration (FDA) conducted an environmental investigation at Atherstone Foods, Inc. (DBA: Glass Onion Catering), in Richmond, CA. Seven retain product samples (consisting of the two implicated Trader Joe’s salads) were collected by FDB and tested by the Food and Drug Laboratory Branch (FDLB) in Richmond, CA. These samples were negative for E. coli O157:H7. The inspection at Atherstone Foods, Inc. did not result in any food safety violations or potential areas of cross-contamination. FDB and FDA continued the outbreak investigation at the grower of the suspected romaine. Investigators inspected Ratto Bros. procedures related to growing, handling and transport of the suspect romaine lettuce. Distribution documents, farm conditions, and water systems used by Ratto Bros. were reviewed in detail. Five of 44 environmental samples collected from areas around the implicated ranch were positive for E. coli O157:H7. One of these samples was obtained from a private road while the other four samples were collected on public roads near the implicated field. The positive samples were not a genetic match to the outbreak strain. FDB could not determine the root cause of contamination to the salads implicated in this outbreak. Investigators identified factors during the investigation at the implicated field that could have contributed to contamination of romaine in a farm environment. These potential factors were wind transferring pathogens from contaminated areas to growing fields and farm equipment contaminating crops after using public roads shared with neighboring cattle operations. Ratto Bros. management responded to the Department’s findings by enhancing their current procedures and adopting new procedures in an effort to prevent potential contamination events in the future.

Sad: E. coli O157 confirmed in death of Mass. child

The Massachusetts Department of Public Health has confirmed the presence of E. coli in its investigation of the recent death of a child in Norfolk County.

e.coli.O157.death.jul.14Melissa Kaye of Braintree says her son Joshua Kaye, 8, died July 7 after a 12-day illness that began with a seemingly curable infection from E. coli bacteria, that turned into kidney failure and ended with a fatal stroke.

This strain of E. coli (0157:H7) often causes stomach problems, but in rare cases, it can cause a condition that attacks the kidneys.

The investigation remains ongoing.

In Braintree, two memorial fundraisers have already been established in Joshua Kaye’s name. His parents opened the Joshua Kaye Memorial Fund at Rockland Trust Bank, 405 Washington St. in Braintree, while family friend Michelle Livingston created the Joshua Kaye Foundation at the site GoFundMe.com.

Since January 1, 2013, there have been 142 cases of E. coli in Massachusetts residents.

Criticism after E. coli outbreak

My food safety friend whom I’ve never met was in the UK press today, criticizing the failure to prosecute a catering firm blamed for an outbreak at the SSE Hydro.

big_bill_in_groundhog-731047Around 22 people were infected, with three hospitalised, after people at the Glasgow entertainment venue ate undercooked burgers from an outlet in January.

Levy Restaurants was held responsible for the outbreak by the Public Health Protection Unit in a report.

Glasgow City Council is to take no further action after being reassured the firm had made changes to the way it prepares food.

But Professor Hugh Pennington, emeritus professor of bacteriology at Aberdeen University, said he is surprised the city council is to take no legal action.

He said: “They have to pay a price by appearing in court.”

He wants “rigorous” action to reassure the public.

Levy’s owners Compass Group said it took food hygiene very seriously and had robust systems in place to ensure the highest standards are maintained.

Uh huh. Keep up the good fight, Hugh.

10 sick, two hospitalized in UK E. coli day care outbreak

Two children are in hospital after a suspected E. coli outbreak at a nursery in Cheshire.

sorenne.nurseryPublic health officers said the children, who both go to the Chrysalis Day Nursery in Northwich, were being treated at Leighton Hospital due to “complications.”

In total, seven children and three family members had shown symptoms of the infection, the officers added.

Children and staff at the nursery are being screened as a precaution.

22 sickened: E coli outbreak at Scotland’s Hydro ’caused by under-cooked burgers’ at venue

We wish to assure the public that at this time we have no significant concerns in relation to catering for our patrons.”

That was the statement from SSE Hydro arena in Glasgow as the number stricken by E. coli O157 climbed in Feb. 2014.

big-grillEventually at least 22 people were stricken, and a new report concludes it was due to under-cooking of beef burgers at the venue.

Of the 22 confirmed cases, a total of 19 of those cases attended had eaten beef burgers at the SSE Hydro’s food stall, Big Grill, between Friday 17 and Sunday 19 January 2014.

The remaining three individuals were infected after having household contact with the initial cases.

An investigation by NHS Greater Glasgow and Clyde (NHSGGC) alongside other public health bodies found evidence “strongly suggesting processing errors leading to under-cooking as well as the potential for cross contamination” at The Hydro.

The report concluded: “Descriptive evidence gathered by environmental health officers strongly suggests processing errors leading to under-cooking as well as the potential for cross contamination in the preparation and serving of the beef burger products.

“These processing errors would provide plausible mechanisms for exposure to VTEC (a strain of E coli).”

Health inspectors then visited the popular music venue after reports of the infection to examine how food was prepared by staff.

They found that preparation of food at “The Big Grill” at the venue involved a lack of consistency in the searing and cooking process of burgers.

Inspectors observed inadequacy of temperature monitoring records and weaknesses in temperature monitoring of food to test how cooked items were by staff.

It was also discovered there was “an inappropriate cleaning and disinfection regime, and an absence of documented evidence of a hazard analysis” at the venue.

All of the 19 confirmed primary cases had eaten a six ounce burger served on a bread bun from the Big Grill stall.”

Risk assessment of Escherichia coli O157 illness from consumption of hamburgers in the United States made from Australian manufacturing beef

We analyze the risk of contracting illness due to the consumption in the United States of hamburgers contaminated with enterohemorrhagic Escherichia coli (EHEC) of serogroup O157 produced from manufacturing beef imported from Australia.

BeefAustralia2012We have used a novel approach for estimating risk by using the prevalence and concentration estimates of E. coli O157 in lots of beef that were withdrawn from the export chain following detection of the pathogen.

For the purpose of the present assessment an assumption was that no product is removed from the supply chain following testing. This, together with a number of additional conservative assumptions, leads to an overestimation of E. coli O157-associated illness attributable to the consumption of ground beef patties manufactured only from Australian beef. We predict 49.6 illnesses (95%: 0.0–148.6) from the 2.46 billion hamburgers made from 155,000 t of Australian manufacturing beef exported to the United States in 2012. All these illness were due to undercooking in the home and less than one illness is predicted from consumption of hamburgers cooked to a temperature of 68 °C in quick-service restaurants.

Risk Analysis

Andreas Kiermeier, Ian Jenson, and John Sumner


Thermal inactivation of Escherichia coli O157:H7 and non-O157 shiga toxin–producing Escherichia coli cells in mechanically tenderized veal

Preflattened veal cutlets (ca. 71.5 g, ca. 0.32 cm thick) were surface inoculated with ca. 6.8 log CFU/g of a multistrain cocktail of Escherichia coli O157:H7 (ECOH) or a cocktail made of single strains of serogroups O26, O45, O103, O104, O111, O121, and O145 of Shiga toxin–producing E. coli (STEC) cells and then were mechanically tenderized by passing once through a “Sir Steak” tenderizer.

veal.skilletFor each cooking time, in each of at least three trials, three inoculated and tenderized cutlets, with and without breading, were individually cooked in 15 or 30 ml of canola oil for 0.0, 0.75, 1.0, 1.25, 1.5, 1.75, or 2.25 min per side on an electric skillet set at 191.5°C. The temperatures of the meat and of the skillet were monitored and recorded using a type J thermocouple.

Regardless of the breading or volume of oil used to cook the meat, the longer the cooking times, the higher was the internal temperature of the meat, along with a greater reduction of both ECOH and STEC. The average final internal temperature of the meat at the approximate geometric center ranged from 56.8 to 93.1°C. Microbial reductions of ca. 2.0 to 6.7 log CFU/g and ca. 2.6 to 6.2 log CFU/g were achieved for ECOH and STEC, respectively. Our data also revealed no differences in thermal inactivation of ECOH relative to the volume of oil used to cook nonbreaded cutlets. However, when cooking breaded cutlets, the use of more (30 ml) compared with less (15 ml) cooking oil resulted in greater reductions in pathogen numbers.

To deliver about a 5.0-log reduction of ECOH and STEC, and to achieve the recommended internal temperature of 71.1°C, it was necessary to cook mechanically tenderized veal cutlets for at least 1.5 min per side on a preheated electric skillet set at 191.5°C and containing 15 ml of cooking oil. These data also established that cooking times and temperatures effective for inactivating serotype O157:H7 strains of E. coli in tenderized veal are equally effective against the additional six non-O157 Shiga toxin–producing strains investigated herein.

Journal of Food Protection®, Number 7, July 2014, pp. 1052-1240, pp. 1201-1206(6)

Luchansky, John B.1; Porto-Fett, Anna C. S.2; Shoyer, Bradley A.2; Thippareddi, Harshavardhan3; Amaya, Jesus R.4; Lemler, Michael4


Fate of Escherichia coli O157:H7 and Salmonella on whole strawberries and blueberries of two maturities under different storage conditions

Strawberries and blueberries harvested at or near full-ripe maturity tend to be less firm and more susceptible to bruising during harvest and transport. The objective of this research was to determine the fate of Escherichia coli O157:H7 and Salmonella on bruised and intact surfaces of whole strawberries and blueberries at shipping (2°C) and retail display (15.5°C) temperatures.

pick-your-own-strawberriesStrawberries and blueberries were either purchased from a supermarket or were harvested immediately prior to use; they were bruised using established protocols, were spot inoculated, and were incubated at 2 and 15.5°C. Strawberries, subjected to modified atmospheres, were further transferred to bags and were sealed in with an initial atmosphere of ca. 10% CO2 and 5% O2. Strawberries were sampled at 0, 2, 5, and 24 h and on days 3 and 7; blueberries were sampled on days 0, 1, 3, and 7. After stomaching, samples were enumerated on nonselective and selective media, and populations were recorded as log CFU per berry. At both storage temperatures, population declines for both E. coli O157:H7 and Salmonella were seen under all conditions for strawberries. At 2 ± 2°C, E. coli O157:H7 and Salmonella populations on blueberries declined over 7 days under all conditions. At 15.5 ± 2°C, E. coli O157:H7 populations declined; however, Salmonella populations initially declined but increased to populations near or above initial populations over 7 days on blueberries. No overall significant differences were observed between bruised and intact treatments or between the two maturity levels for strawberries and blueberries. Modified atmospheric conditions did not affect the behavior of E. coli O157:H7 and Salmonella on strawberries at both temperatures.

blueberryThis research indicates that E. coli O157:H7 and Salmonella do not grow on strawberries at shipping or retail display temperatures, even when they are harvested at a maturity prone to bruising; however, Salmonella growth may occur on bruised full ripe blueberries under retail display temperatures.

Journal of Food Protection®, Number 7, July 2014, pp. 1052-1240, pp. 1093-1101(9)

Nguyen, Thao P.1; Friedrich, Loretta M.1; Danyluk, Michelle D.2


Father of Washington E. coli victim continues push for food safety

Sometimes, when he was a teacher, Darin Detwiler would look at his students and realize they were the same age as his son Riley, if Riley were still alive.

rileyDRiley was just 17 months old when he lost his life 21 years ago. He was one of four youngsters in the Northwest who died from an E. coli O157 outbreak linked to contaminated, undercooked meat at Jack in the Box restaurants.

Detwiler said seeing his students, alive and healthy, reminded him of the importance of trying to be a good teacher, and of weaving the subject of food safety into his classroom content.

“There’s a reason why I am alive and my son is not,” he said. “If I’m going to justify why I’m alive, maybe it’s to continue to be of service and to make a difference in this world. It helps me to go to bed at night.”

Detwiler and his wife, Vicki, were living in Bellingham when news of the E. coli outbreak went public in mid-January 1993. At the time, they were parents to two boys, Joshua, 9, and Riley.

As a precaution, they stayed away from Jack in the Box, but Riley became sick after being exposed to an infected child in day care.

Riley soon showed signs of illness and was flown to a Seattle hospital in serious condition on Feb. 2. Despite major surgery and intensive care, he died 18 days later.

Nearly 500 people were infected by eating the contaminated hamburger meat in Washington and three other Western states.

CANADA: Differing populations of endemic bacteriophages in cattle shedding high and low numbers of Escherichia coli O157:H7 bacteria in feces

The objectives of this study were to identify endemic bacteriophages (phages) in the feedlot environment and determine relationships of these phages to Escherichia coli O157:H7 from cattle shedding high and low numbers of naturally occurring E. coli O157:H7.

750px-PhageExterior.svgAngus crossbred steers were purchased from a southern Alberta (Canada) feedlot where cattle excreting ≥104 CFU · g−1 of E. coli O157:H7 in feces at a single time point were identified as supershedders (SS; n = 6), and cattle excreting <104 CFU · g−1 of feces were identified as low shedders (LS; n = 5).

Fecal pats or fecal grabs were collected daily from individual cattle for 5 weeks. E. coli O157:H7 in feces was detected by immunomagnetic separation and enumerated by direct plating, and phages were isolated using short- and overnight-enrichment methods. The total prevalence of E. coli O157:H7 isolated from feces was 14.4% and did not differ between LS and SS (P = 0.972). The total prevalence of phages was higher in the LS group (20.9%) than in the SS group (8.3%; P = 0.01). Based on genome size estimated by pulsed-field gel electrophoresis and morphology determined by transmission electron microscopy, T4- and O1-like phages of Myoviridae and T1-like phage of Siphoviridae were isolated. Compared to T1- and O1-like phages, T4-like phages exhibited a broad host range and strong lytic capability when targeting E. coli O157:H7. Moreover, the T4-like phages were more frequently isolated from feces of LS than SS, suggesting that endemic phages may impact the shedding dynamics of E. coli O157:H7 in cattle.

Appl. Environ. Microbiol. July 2014 vol. 80 no. 13 3819-3825 doi: 10.1128/AEM.00708-14

J. Hallewella,b, Y. D. Niuc, K. Munnsb, T. A. McAllisterb, R. P. Johnsond, H.-W. Ackermanne, J. E. Thomasa and K. Stanfordc