Tag Archives: Stec

Burgers may need higher cooking temperature to be safe from E. coli

Posted on by
1

Food safety friend Lynn McMullen at the University of Alberta, and others have found that cooking ground beef at 71C — the level of heat long advised by Health Canada — does not always eliminate all the strains of Escherichia coli.

mcmullen.e.coli.hamburger“We’ve been hammering consumers for years to cook chicken properly, to handle it properly, and to do the same with ground beef but still we seem to have these outbreaks of E. coli (attributed to hamburgers),” said food microbiologist McMullen.

“Does this explain why? It might.”

McMullen, fellow food microbiologist Michael Gänzle, and several graduate students, first became aware of the inconsistent behaviour of E. coli eight years ago.

For decades, scientific papers about the thermal killing of microorganisms have noted that there were sometimes survivors. But little attention was paid to that information until 2008, when McMullen and Gänzle assigned a student to look for differences in thermal survival amongst organisms in a large collection of E. coli from beef, which the U of A happens to house.

The first student, Elena Dlusskaya, showed that one organism had survived for 70 minutes at 60C. Both professors felt her study must be flawed, because most E. coli are killed just a few seconds after such heat application. Repeating her experiments twice produced the same odd results.

Then Dlusskaya compared her cultures to those from other labs, which already had published survival values. Again, she found that some of the U of A’s cultures were behaving differently.

“These organisms aren’t supposed to survive, but every once in a while they do,” said McMullen. “So we decided to find out why. We looked at the genomes to see what was different.”

Working with postdoctoral fellow Ryan Mercer, they discovered a suite of 16 genes that are found only in the highly heat-resistant strains of E. coli under wet conditions (i.e. fresh meat). This genomic grouping is called the locus of heat resistance, or LHR.

Hunting through the genome databases for LHR, they saw that it exists in about two per cent of all E. coli in the databases and is present in both the harmless and pathogenic strains.

barfblog.Stick It In“If it’s in two per cent of all E. coli, and in pathogenic E.coli, there’s the potential that a pathogen could survive the standard cooking protocols for ground beef. It could mean we have to change the guidelines for cooking meat, because 71C may not be enough.”

Salt also makes E. coli bacteria heat resistant, though McMullen and the other researchers don’t know why.

Though McMullen and the other researchers haven’t discovered what temperature will ultimately kill all E. coli, McMullen recommended using a thermometer and cooking meat at 71 C to 73 C. “It doesn’t matter when you’re grilling any ground meat, you should be using a thermometer.”

Genetic determinants of heat resistance in Escherichia coli

Front Microbiol. 2015; 6: 932.

Published online 2015 Sep 9. doi:  10.3389/fmicb.2015.00932

Ryan G. Mercer, Jinshui Zheng, Rigoberto Garcia-Hernandez, Lifang Ruan, Michael G. Gänzle, and Lynn M. McMullen

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4563881/

Escherichia coli AW1.7 is a heat resistant food isolate and the occurrence of pathogenic strains with comparable heat resistance may pose a risk to food safety. To identify the genetic determinants of heat resistance, 29 strains of E. coli that differed in their of heat resistance were analyzed by comparative genomics. Strains were classified as highly heat resistant strains, exhibiting a D60-value of more than 6 min; moderately heat resistant strains, exhibiting a D60-value of more than 1 min; or as heat sensitive. A ~14 kb genomic island containing 16 predicted open reading frames encoding putative heat shock proteins and proteases was identified only in highly heat resistant strains. The genomic island was termed the locus of heat resistance (LHR). This putative operon is flanked by mobile elements and possesses >99% sequence identity to genomic islands contributing to heat resistance in Cronobacter sakazakii and Klebsiella pneumoniae. An additional 41 LHR sequences with >87% sequence identity were identified in 11 different species of β- and γ-proteobacteria. Cloning of the full length LHR conferred high heat resistance to the heat sensitive E. coli AW1.7ΔpHR1 and DH5α. The presence of the LHR correlates perfectly to heat resistance in several species of Enterobacteriaceae and occurs at a frequency of 2% of all E. coli genomes, including pathogenic strains. This study suggests the LHR has been laterally exchanged among the β- and γ-proteobacteria and is a reliable indicator of high heat resistance in E. coli.

Two students in Kenya die after E. coli outbreak at school for developmentally challenged

Posted on by
Reply

An outbreak of E. coli has claimed the lives of two students at the Meru School for the Mentally Challenged, with several others being admitted to hospital.

e.coli.meru.schoolThe school has been quarantined with medical workers camping there to monitor those under medication and prevent the spread of the bacteria.

Close to 50 pupils with severe abdominal cramps and diarrhoea were admitted to hospital but by Tuesday, only 10 were still undergoing treatment.

Meru Health executive William Muraah said the students did not die of cholera as had earlier been reported, adding that food and water contamination could have been the cause of the outbreak.

“Only a conclusive culture test can reveal whether it is cholera. Test results say the students died of E. coli.

Blame the consumer, flour edition: 38 sick with E. coli O121 linked to General Mills

Posted on by
3

Amy was cooking some gluten-free pie shit the other night and she asked me what the temp should be – we have conversations like that in our family – and I said I’m not too concerned about the interior fruit filling, but make sure the pastry exterior hits 165F.

sifting_flour-chris_marchantThat was because of past outbreaks.

And now this.

General Mills is recalling about 10 million pounds of flour after an E. coli outbreak associated with flour sickened 38 people in 20 states.

Mike Hughlett of the Star Tribune reports the Golden Valley-based packaged food giant on Tuesday announced the voluntary recall of some lots of its signature Gold Medal flour, along with flour sold under the Wondra and Signature Kitchens brands. Signature Kitchens is a store brand sold at several major U.S. grocery chains including Safeway, Albertson’s, Jewel, Vons and Acme.

The federal Centers for Disease Control (CDC) said Tuesday there have been 10 hospitalizations associated with the outbreak, but no deaths have been reported.

The CDC has not yet released names of states affected by the recall, but the Minnesota Department of Health confirmed that three of the 38 people sickened lived in the Twin Cities area. All three — two adults and a child — have since recovered, and none were hospitalized, said Doug Schultz, a health department spokesman.

State and federal health authorities have been investigating an outbreak of E. coli O121 from Dec. 21 to May 3, General Mills said in a statement. The Minnesota health department said the Minnesota cases occurred in January and March.

The Centers for Disease Control found that about half of the 38 sickened people reported making homemade food with flour before becoming ill. Some reported using a General Mills brand of flour. Some also might have consumed raw dough or batter.

General Mills said it has not found E. coli O121 in any of its products or at its flour facilities, nor has it received any illness reports directly from consumers. The flour involved in the recall was mostly produced at General Mills’ Kansas City plant.

But Liz Nordlie, president of General Mills Baking division, did say, Consumers are reminded to not consume any raw products made with flour. Flour is an ingredient that comes from milling wheat, something grown outdoors that carries with it risks of bacteria which are rendered harmless by baking, frying or boiling. Consumers are reminded to wash their hands, work surfaces, and utensils thoroughly after contact with raw dough products or flour, and to never eat raw dough or batter.

“As a leading provider of flour for 150 years, we felt it was important to not only recall the product and replace it for consumers if there was any doubt, but also to take this opportunity to remind our consumers how to safely handle flour.”

Officials investigate link between 3 children with shiga-toxin E. coli and Fairfax Creek in Calif.

Posted on by
Reply

Richard Halstead of the Marin Independent Journal writes two young children, one a 2-year-old Fairfax resident, have been diagnosed with a toxin-producing form of E. coli, and Marin public health officials are investigating the possibility that the source of the bacteria was a creek that runs through Peri Park in downtown Fairfax.

periparkA third child, a 3-year-old San Anselmo resident, has also displayed symptoms consistent with a diagnosis of E. coli, but tests results are still pending. The second confirmed E. coli case is a 3-year-old resident of Truckee. All three children played in Peri Park’s Fairfax Creek not long before becoming ill.

“We have not yet confirmed that water contamination is the source,” said Dr. Lisa Santora, Marin County’s deputy public health officer.

Rebecca Ng, deputy director of Marin County’s environmental health department, said, “We took water samples this morning.”

Test results from those samples weren’t available Thursday; but Santora said they will show only whether there is coliform bacteria in the creek, not whether the type of E. coli that caused these illnesses is present there. Coliform bacteria is found in the intestinal tract of humans and other animals.

Fairfax Town Manager Garrett Toy said the creek is polluted from storm drain runoff and could contain feces from dogs, deer or other animals.

“It’s a creek; there is always going to be bacteria in the creek,” Toy said. “You really shouldn’t be consuming water from the creek even if it is by accident.”

Santora said the Truckee child was the first to become ill and was hospitalized May 8-9 at Marin General Hospital. The Fairfax child became ill on May 15, and the San Anselmo child became ill on May 21.

Neither of the Marin County children have been hospitalized. Santora said she didn’t have current information on the medical condition of any of the children.

The illnesses have caused a flurry of postings on the social media site Nextdoor. According to one posting, the Truckee child was transferred to the University of California at Davis Medical Center in Sacramento after his kidneys began to fail and is responding well to intravenous therapy and blood transfusions.

Nickelback? Really? So much for Trudeau being cool and Shiga-toxin producing E. coli in pigs

Posted on by
Reply

Still a deafening silence from public health types over whether or not people are definitively sick or just sick from Cantran Meat Co. raw pork and pork organ products linked to an E, coli O157 outbreak in Alberta.

TrudeauNickelbackSmallIt is a long weekend in Canada – Queen Victoria’s birthday or something as an excuse to go camping in the cold and mark the start of summer – so don’t expect anything public soon.

But an astute conversationalist did send along this abstract from last month to help answer the question, what is Shiga-toxin producing E. coli doing in pig?

Abstract

Similar to ruminants, swine have been shown to be a reservoir for Shiga toxin-producing Escherichia coli (STEC), and pork products have been linked with outbreaks associated with STEC O157 and O111:H-.

STEC strains, isolated in a previous study from fecal samples of late-finisher pigs, belonged to a total of 56 serotypes, including O15:H27, O91:H14, and other serogroups previously associated with human illness. The isolates were tested by polymerase chain reaction (PCR) and a high-throughput real-time PCR system to determine the Shiga toxin (Stx) subtype and virulence-associated and putative virulence-associated genes they carried. Select STEC strains were further analyzed using a Minimal Signature E. coli Array Strip. As expected, stx2e (81%) was the most common Stx variant, followed by stx1a (14%), stx2d (3%), andstx1c (1%).

kid_pig_kissThe STEC serogroups that carried stx2d were O15:H27, O159:H16 and O159:H-. Similar to stx2aand stx2c, the stx2d variant is associated with development of hemorrhagic colitis and hemolytic uremic syndrome, and reports on the presence of this variant in STEC strains isolated from swine are lacking. Moreover, the genes encoding heat stable toxin (estIa) and enteroaggregative E. coli heat stable enterotoxin-1 (astA) were commonly found in 50 and 44% of isolates, respectively. The hemolysin genes,hlyA and ehxA, were both detected in 7% of the swine STEC strains. Although the eae gene was not found, other genes involved in host cell adhesion, including lpfAO113 and paa were detected in more than 50% of swine STEC strains, and a number of strains also carried iha, lpfAO26, lpfAO157, fedA, orfA, and orfB.

The present work provides new insights on the distribution of virulence factors among swine STEC strains and shows that swine may carry Stx1a-, Stx2e-, or Stx2d-producing E. coli with virulence gene profiles associated with human infections.

Characterization of Shiga toxin subtypes and virulence genes in porcine Shiga toxin-producing Escherichia coli

Frontiers in Microbiology, 21 April 2016, http://dx.doi.org/10.3389/fmicb.2016.00574

Gian Marco Baranzoni, Pina M. Fratamico, Jayanthi Gangiredla, Isha Patel, Lori K. Bagi, Sabine Delannoy, Patrick Fach, Federica Boccia, Aniello Anastasio and Tiziana Pepe

http://journal.frontiersin.org/article/10.3389/fmicb.2016.00574/full

Penn. schools get grant to study shiga-toxin producing E. coli

Posted on by
Reply

The Souderton Area School District received $250,000 from the U.S. Department of Agriculture on Monday to help fund a career-exploration program for students who want safe food.

stec.cap.SoudertonThe money is part of a $25 million grant named after a bacteria commonly associated with foodborne illnesses.

The STEC-CAP grant, also known as the Shiga toxin Escherichia coli Coordinated Agricultural Project, will connect Souderton students to researchers across the country whose objectives are to identify and eliminate pathogenic E. coli on food, said Kyle D. Longacre, the high school’s assistant principal.

The University of Nebraska-Lincoln directs the research, which involves participants from 13 colleges and universities.

According to Longacre, a partnership between the USDA and Souderton schools has prospered since 2014 when 10 high school teachers were trained about food safety methods, bacterial growth labs and the latest research related to Shiga toxin E. coli.

The money will also help Souderton’s Pathway 360 program, which places motivated students in the professional workplace with mentors.

Longacre, who leads Pathway 360, said the high school would use the money to spread the word about food safety and to get students to consider a career in food science and agriculture.

“It’s been a tremendously creative program,” said Dr. Rodney Moxley, a professor in the School of Veterinary Medicine and Biomedical Science at the University of Nebraska-Lincoln. “Pathway 360 has its own inherent accomplishments in that you are helping students to get jobs.”

According to the district, the money also will help fund the possible expansion of partnerships with Upper Perkiomen, Norristown and other school districts.

Longacre said students in Pathway 360 take part in an initiative called “Message to the Masses” in which Souderton’s Design, Marketing and Communications club partnered with three advertising agencies to create slogans for the USDA’s program on safe handling of beef.

Students in the design and marketing club presented their ideas to advisers following Monday’s announcement of the grant. The ideas were then critiqued by advisers with the STEC-CAP grant program. Longacre said the advisers will select the best idea, and the USDA will fly five or more Souderton students to Nebraska in June to present their ideas to a national council of STEC-CAP advisers.

Risk reduction: Irradiation of strawberries

Posted on by
Reply

Strawberries are vulnerable to harboring microbial pathogens because they are generally not washed due to their perishable nature. The focus of this study was to quantify the reduction in infection risks associated with non-O157 Shiga toxin producing E. coli serotypes contaminated strawberries if the strawberries are exposed to low doses ∼1 kGy (kiloGray) of electron beam (eBeam) irradiation.

strawberry.irradiationA cocktail of six serotypes of non O157 E. coli namely, O26:H11, O45:H2, O103:H2, O111:NM, O121:H19, and O145 was employed. Strawberry puree rather than whole strawberries were used in this study to ensure dose uniformity that is critical for accurate interpretation of microbial reduction.

The results show that when these serotypes are exposed to ≤1 kGy eBeam dose, there is approximately 4-log reduction in their numbers when they are present within a strawberry matrix (puree). Quantitative microbial risk assessments suggest that if a typical strawberry serving (150 g) was heavily contaminated (∼105 CFU/serving size), 2 out of 10 susceptible individuals (20%) would get sick (without eBeam treatment). However, if these contaminated strawberries had been treated with 1 kGy of eBeam dose, the infection risks would have be significantly reduced to approximately 4 out of every 100,000 individuals (0.004%). Similarly, even at low levels of contamination (∼102 CFU/serving), the infection risks would be reduced from 6 out of 10,000 susceptible individuals to approximately 4 out of 100 million susceptible individuals.

Quantifying the reduction in potential infection risks from non-O157 Shiga toxin producing E. coli in strawberries by low dose electron beam processing

Food Control; Available online 7 May 2016; doi:10.1016/j.foodcont.2016.04.057

Shima Shayanfara, Kristina Menab, Suresh D. Pillaia

http://www.sciencedirect.com/science/article/pii/S0956713516302444

But will it make fewer people barf? Chipotle hires more food safety expertise

Posted on by
1

Reuters reports that David Acheson, a former official at the U.S. Food and Drug Administration and the U.S. Department of Agriculture, and David Theno, a food safety consultant and former Jack in the Box executive who is credited with fixing food safety at the fast-food chain following a deadly E. coli outbreak in the 1990s, have joined the payroll at Chipotle Mexican Grill.

chipotle.burrito.vomitThey join James Marsden, a former meat science professor at Kansas State University, and Mansour Samadpour, chief executive of IEH Laboratories & Consulting Group.

That’s a lot of egos in one sandbox.

Or as friend of the barfblog, Don Schaffner, a food science professor at Rutgers University, told Reuters,“If I had to put together a dream team to fix something, you could do a lot worse,” But, he added, “I’ve begun to wonder a little bit about too many cooks. Each of those guys is going to have a perspective on what to do to fix the problem.”

Spokesman Chris Arnold confirmed the consultants were retained last year but would not say when or detail their duties. He did say Marsden, as executive director of food safety, would have “primary responsibility for our food safety programs.”

Expanding its complement of food safety experts is part of Chipotle’s effort to rebound from a spate of disease outbreaks – including E. coli, salmonella and norovirus – last year that crushed sales, repulsed customers and slashed $6 billion off its market valuation.

“We have committed to establishing Chipotle as an industry leader in food safety, and we have assembled an extremely capable team to help us achieve that goal,” Arnold told Reuters.

chipotle_ad_2Chipotle declined to make members of the team available for interviews.

Michael Doyle, director of the Center for Food Safety at the University of Georgia, said he expected the group’s focus “would likely be more on food safety preventive controls and less on food testing.”

Chipotle’s initial response emphasized testing ingredients for pathogens with the goal of stopping any source of illness from getting into its restaurants.

Acheson criticized the Chipotle for relying too heavily on that one approach. “I’m not a believer that you can test your way to safety,” he told Reuters in early December.

At the time, he said the focus should be on improving food sourcing and handling practices, including how suppliers are approved, “how they are leveraged in terms of training, storing, handling, and preparing of food.”

Arnold said Chipotle continues to work with the IEH testing firm. Its more recent changes have focused on food preparation. For instance, Chipotle said on its latest earnings call that it had started blanching bell peppers in an effort to kill germs.

family.guy.diarrheaThe chain also has cut some small suppliers. Kenter Canyon Farms said it lost business providing oregano to Chipotle through a third-party distributor.

“When that whole scandal happened with the E. coli, when they revamped their food safety. They cut ties with a lot of growers,” said Mark Lopez, sales director for the farm.

Chipotle’s Arnold said the chain would continue to support smaller farms, and has committed to spending $10 million to help them meet its standards. But he said the company has noted that it may be difficult for “some of our smaller suppliers to meet our heightened food safety standards.”

Fresh or frozen, deep-fried or baked: Reducing E. coli in meatballs

Posted on by
Reply

I’d always use a tip-sensitive digital thermometer to account for variations in cooking appliances, degrees of thawdiness (yes, I’m making up words) initial bacterial loads.

meatballs2We investigated the effects of deep-frying or oven cooking on inactivation of Shiga toxin–producing cells of Escherichia coli (STEC) in meatballs.

Finely ground veal and/or a finely ground beef-pork-veal mixture were inoculated (ca. 6.5 log CFU/g) with an eight-strain, genetically marked cocktail of rifampin-resistant STEC strains (STEC-8; O111:H, O45:H2, O103:H2, O104:H4, O121:H19, O145:NM, O26:H11, and O157:H7). Inoculated meat was mixed with liquid whole eggs and seasoned bread crumbs, shaped by hand into 40-g balls, and stored at −20°C (i.e., frozen) or at 4°C (i.e., fresh) for up to 18 h. Meatballs were deep-fried (canola oil) or baked (convection oven) for up to 9 or 20 min at 176.7°C (350°F), respectively. Cooked and uncooked samples were homogenized and plated onto sorbitol MacConkey agar with rifampin (100 μg/ml) followed by incubation of plates at 37°C for ca. 24 h. Up to four trials and three replications for each treatment for each trial were conducted.

Deep-frying fresh meatballs for up to 5.5 min or frozen meatballs for up to 9.0 min resulted in reductions of STEC-8 ranging from ca. 0.7 to ≥6.1 log CFU/g. Likewise, reductions of ca. 0.7 to ≥6.1 log CFU/g were observed for frozen and fresh meatballs that were oven cooked for 7.5 to 20 min.

This work provides new information on the effect of prior storage temperature (refrigerated or frozen), as well as subsequent cooking via deep-frying or baking, on inactivation of STEC-8 in meatballs prepared with beef, pork, and/or veal. These results will help establish guidelines and best practices for cooking raw meatballs at both food service establishments and in the home.

Effect of deep-frying or conventional oven cooking on thermal inactivation of Shiga toxin–producing cells of Escherichia coli in meatballs

Journal of Food Protection®, Number 5, May 2016, pp. 696-889, pp. 723-731(9)

Porto-Fett, Anna C. S.; Oliver, Michelle; Daniel, Marciauna; Shoyer, Bradley A.; Stahler, Laura J.; Shane, Laura E.; Kassama, Lamin S.; Jackson-Davis, Armitra; Luchansky, John B.

http://www.ingentaconnect.com/contentone/iafp/jfp/2016/00000079/00000005/art00005

 

Waaaah: Chipotle still doesn’t get it, whinges about CDC reporting of E. coli outbreaks

Posted on by
Reply

According to Reuters, the U.S. Centers for Disease Control and Prevention has pushed back against complaints from Chipotle Mexican Grill that the health agency misinformed the public with its reporting of certain E. coli cases linked to the burrito chain.

finster.bugs.bunnyThe CDC, in a letter to a lawyer representing Chipotle, said it believes its web updates on the outbreaks served to protect and inform the public.

The CDC’s response, which was posted online this week and dated April 15, said its updates provided people who may have become sick after eating at Chipotle restaurants with information they might have needed to be diagnosed and treated for E. coli O26.

In December, Chipotle’s lawyer said in a letter to the CDC that some of the agency’s updates were confusing and unclear and that their release “only acts to create public panic.”

For a supposedly modernly hipster chain, Chipotle is purely old school when it comes to going public: patronizing, paternalistic, pathetic.