Category Archives: E.coli O157:H7

Research – Microbiological Survey of Wheat Flour Sold at Retail in Canada, 2018-2019

Journal of Food Protection

Following two O121 STEC outbreaks linked to wheat flour, this study was conducted to gain baseline information on the occurrence of bacterial pathogens and levels of indicator organisms in wheat flour in Canada. A total of 347 pre-packaged wheat flour samples were analyzed for Salmonella spp., Shiga Toxin-Producing Escherichia coli (STEC), Listeria monocytogenes ( L. monocytogenes ) , aerobic colony count (ACC), total coliforms, and generic Escherichia coli ( E. coli ) . Salmonella spp. and O157 STEC were not detected in any of the samples. L. monocytogenes was identified in two samples (0.6%) at levels below the limit of detection (<0.7 log CFU/g). Non-O157 STEC were isolated from six samples (1.7%) and were characterized for the presence of STEC virulence genes: stx 1, stx 2 and subtypes, eae , hlyA, and aggR . One O103:H25 STEC isolate carried virulence genes ( stx 1 a + eae ) that are known to be capable of causing diarrhea and/or bloody diarrhea in humans. Of the five remaining non-O157 STEC isolates, four carried single stx 2a or stx 2c genes and were considered to have the potential of causing diarrhea. The remaining non-O157 STEC isolate ( stx 2 ), while not a priority non-O157 STEC was not available for sequencing and thus its potential to cause illness is unknown. ACC, total coliforms, and generic E. coli were detected   in 98.8%, 72.6% and 0.6% of the flour samples. The mean counts of ACC were greater in whole-wheat flour as compared to the other flour types tested ( p <0.001). The results of this study suggest that the occurrence of O157 STEC and Salmonella  is low, but the occurrence of non-O157 STEC in wheat flour with the potential to cause human illness of diarrhea is relatively common. Therefore, the consumption of raw flour could increase the likelihood of STEC infections. Further research is merited for potential risk mitigation strategies within the food production system and with consumers.

UK – Investigation – STEC E.coli O157- 2017 Frozen Beef Burgers

Cambridge Press

In November 2017, Public Health England identified an outbreak of Shiga toxin-producing Escherichia coli O157:H7 in England where whole genome sequencing results indicated cases were likely to be linked to a common source, and began investigations.

Hypothesis generation included a review of enhanced surveillance data, a case-case study and trawling interviews. The hypothesis of interest was tested through the administration of focussed questionnaires and review of shopping history using loyalty card data. Twelve outbreak cases were detected, eight were hospitalised and four developed haemolytic uraemic syndrome. Frozen beef burgers supplied by a national retailer were identified as the vehicle of the outbreak. Testing of two left-over burger samples obtained from the freezers of two separate (unlinked) cases and a retained sample from the production premises were tested and found to be positive for the outbreak strain. A voluntary recall of the burgers was implemented by the retailer. Investigations at the production premises identified no contraventions of food safety legislation. Cooking guidance on the product packaging was deemed to be adequate and interviews with the cases/carers who prepared the burgers revealed no deficiencies in cooking practices at home. Given the long-shelf life of frozen burgers, the product recall likely prevented more cases.

USA – Outbreak Investigation of E. coli O157:H7: Unknown Food (Fall 2020)


The FDA and CDC, in collaboration with state and local partners, is investigating illnesses in a third multistate outbreak of E.coli O157:H7 infections this Fall.

On November 6, 2020, the Michigan Department of Agriculture and Rural Development (MDARD) reported that as a part of routine sampling, they collected a product sample of romaine lettuce for testing. The sample tested positive for E. coli O157:H7 and subsequent whole genome sequencing (WGS) analysis determined that the E. coli O157:H7 present in the samples matches the strain that has caused illnesses in this outbreak.

The strain of E. coli found in the Michigan sample is a third distinct strain not genetically related to the strains causing two distinct multi-state outbreaks of Shiga-toxin producing E. coli O157:H7 (STEC) that FDA and CDC announced on October 28, 2020. At this time, a specific food has not been linked to either of those outbreaks.

On November 6, 2020, Tanimura & Antle, Inc. recalled packaged single head romaine lettuce with a pack date of 10/15/2020 or 10/16/2020 due to possible contamination with E. coli O157:H7. The firm recalled this product based on test results from a product sample collected and analyzed by MDARD before the WGS analysis showing the match to the outbreak strain was completed.

FDA and state partners are working with the firm to determine if additional romaine should be recalled.

At this time, there is not enough epidemiologic and traceback evidence to determine if ill people in this outbreak were exposed to romaine lettuce from Tanimura & Antle, Inc. Additional information will be provided as it becomes available.


Consumers, restaurants, and retailers, should not eat, sell, or serve Tanimura & Antle, Inc. brand packaged single head romaine lettuce with a pack date of 10/15/2020 or 10/16/2020.

USA – Consumer Advisory: Romaine lettuce grown by Tanimura & Antle tests positive for E. coli


Romaine lettuce

LANSING, Mich. – The Michigan Department of Agriculture and Rural Development (MDARD) is advising consumers not to eat Tanimura & Antle brand romaine lettuce packed as single heads due to food safety concerns.

A routine sample of the lettuce collected at a Walmart in Comstock Park, MI, and tested by MDARD’s Laboratory Division confirmed positive for E. coli 0157:H7. Further analysis conducted by the Michigan Department of Health and Human Services laboratory determined that the strain of E. coli recovered from the product sample is highly related genetically to E. coli causing two recent illnesses in Michigan.

The lettuce was sold in a zip-top clear plastic bag with a blue label and white lettering.  It has the UPC number 0-27918-20314-9 and a white sticker indicating it was packed in Salinas, California on October 15, 2020.

Consumers should discard this product or return it to the place of purchase. If you think you or a family member have become ill from consuming any of these products, please seek immediate medical attention.

E. coli can cause serious or life-threatening illness in some individuals. Symptoms of Shiga toxin-producing E. coli (STEC) infection vary for each person, but often include severe stomach cramps, diarrhea (often bloody), and vomiting. Some people may have a fever, which usually is not very high (less than 101˚F/38.5˚C). Most people get better within 5 to 7 days. Some infections are very mild, but others are severe or even life-threatening. People usually get sick from Shiga toxin-producing E. coli (STEC) 2 to 8 days (average of 3 to 4 days) after ingesting the bacteria. Some people with a STEC infection may get a type of kidney failure called hemolytic uremic syndrome (HUS). E. coli infection is usually diagnosed by testing a stool sample.

USA – Mystery surrounds two new E. coli outbreaks with genetic links to past Romaine events

Food Safety News

With Halloween only hours away,  two new E. coli outbreaks have shown up to haunt the nation’s Romaine growers because genetic links to the past have been discovered.

The two outbreaks of Shiga toxin-producing E. coli O157: H7 (STEC) illnesses are under investigation by the Food and Drug Administration (FDA), Centers for Disease Control, and Prevention (CDC), along with various state and local health departments.

“We do not know what food is causing people to get sick or whether it involves an FDA-regulated food product,” said  Frank Yiannas, FDA Deputy Commissioner for Food Policy and Response.  “However, we have seen similar recurring, emerging, or persistent strains of E. coli in recent outbreaks. E. coli O157: H7 can contaminate many foods, and we cannot assume that the current outbreaks are linked to historically associated foods like romaine and other leafy greens. There is no information currently to indicate that people should avoid any specific food.”

Research – The effects of environmental factors on the prevalence and diversity of bacteriophages lytic against the top six non‐O157 Shiga toxin‐producing Escherichia coli on an organic farm

Wiley Online

Bacteriophages (or phages) specific to Shiga toxin‐producing Escherichia coli (STEC) strains are frequently isolated from animal‐associated environments primarily because ruminant animals are the natural reservoir of STEC. However, little is known about these phages in produce‐growing environments. The objective of this study was to determine the effects of environmental factors on the prevalence of the phages lytic against O157 and the top six non‐O157 STEC on an organic farm. A total of 370 samples were collected from an organic farm, containing animal‐active and produce‐growing areas, for 1 year. A bacterial cocktail, including nonpathogenic and pathogenic Ecoli strains, was used for phage isolation. Meanwhile, culture methods and PCR were used to isolate STEC strains. Weather information was also collected for each sampling trip. Twenty‐eight samples contained phages lytic against STEC (or STEC‐infecting phages), of which 26 were collected from the animal‐active area. Moreover, the winter season had a higher phage prevalence than other seasons, likely due to high rain precipitation. The phages belonging to the Myoviridae family and those lytic against STEC O103 were the most prevalent. One Ecoli O103:H2 was isolated from a water sample where no STEC O103‐infecting phages were found. Additionally, no STEC O103 was present in the samples containing STEC O103‐infecting phages. The findings indicate that animal is the primary factor contributing to the prevalence of the STEC‐infecting phages in the surrounding environment of the organic farm, and the presence of these phages contributes to a negative correlation with their STEC hosts.

France – Product recall: Picodon aop x2, x5 – Guinguette x6 – Goat cheese x3 from Les Fromagers Fermiers du Peytot


Product recall: Picodon aop x2, x5 - Guinguette x6 - Goat cheese x3 from Les Fromagers Fermiers du Peytot


Presence of Escherichia coli O157: H7


People who hold the product in question are asked not to consume them – and more particularly young children, pregnant women, immunocompromised people and the elderly – and to return them to the point of sale where they were purchased.

People who have consumed it and who present symptoms such as diarrhea, abdominal pain or vomiting should consult their doctor as soon as possible, mentioning this consumption and the possible link with the bacterium Escherichia coli.

If there are no symptoms within 10 days of consuming the affected products, there is no need to worry and consult a doctor.

The E. coli bacterium is naturally present in the digestive microflora of humans and warm-blooded animals. Some strains of E. coli are pathogenic, and can be responsible in humans for various disorders ranging from mild diarrhea to more serious forms such as hemorrhagic diarrhea or severe kidney damage such as HUS, mainly in young children.


▸ Type of packaging
Rolls x6, x5, x3, x2, tray x2 or bare

▸ Lots
• 23110
• 23810
• 24510
• 25210
• 25910
• 26610
• 27310

▸ Health
stamp FR 07.176.001 CE

▸ Marketing period
from August 17, 2020 to October 14, 2020

▸ Consumer service contact
La Sarl Les Fromagers Fermiers du Peytot is available to consumers to answer their questions by email at

▸ Source

Research – Recovery Rate of Cells of the Seven Regulated Serogroups of Shiga Toxin-Producing Escherichia coli from Raw Veal Cutlets, Ground Veal, and Ground Beef from Retail Stores in the Mid-Atlantic Region of the United States

Journal of Food Protection

A total of 482 veal cutlet, 555 ground veal, and 540 ground beef samples were purchased from retail establishments in the Mid-Atlantic region of the U.S. over a non-contiguous, two-year period between 2014 and 2017. Samples (325 g each) were individually enriched and screened via real-time PCR for all seven regulated serogroups of Shiga toxin-producing Escherichia coli (STEC). Presumptive STEC positive samples were subjected to serogroup-specific immunomagnetic separation and plated onto selective media. Up to five isolates typical for STEC from each sample were analyzed via multiplex PCR for both the virulence genes (i.e., eae , stx 1 and/or stx 2 , and ehxA ) and serogroup-specific gene(s) for the seven regulated STEC serogroups. The recovery rates of non-O157 STEC from veal cutlets (3.94%, 19 of 482 samples) and ground veal (7.03%, 39 of 555 samples) were significantly higher (P < 0.05) than that from ground beef (0.93%, 5 of 540 samples). In contrast, only a single isolate of STEC O157:H7 was recovered; this isolate originated from one (0.18%) of 555 samples of ground veal. Recovery rates for STEC were not associated with state, season, packaging type, or store type (P > 0.05), but were associated with brand and fat content (P < 0.05). Pulsed-field subtyping of the 270 viable/confirmed STEC isolates from the 64 total samples testing positive revealed 78 pulsotypes (50 to 80% similarity) belonging to 39 pulsogroups, with ≥90% similarity among pulsotypes within pulsogroups. Also, multiple isolates from the same sample displayed an indistinguishable pulsotype for 43 of 64 (67.7%) samples testing positive.  These findings support related data from regulatory sampling exercises over the past decade and confirm that recovery rates for the regulated STEC serogroups are appreciably higher for raw veal compared to raw beef samples as was also observed herein for meat purchased at food retailers in the Mid-Atlantic region of the U.S.

Research – Thermal Resistance of Single Strains of Shiga Toxin-Producing Escherichia coli O121:H19 and O157:H7 Based on Culture Preparation Method and Osmolyte-Reduced Water Activity

Journal of Food Protection

Pathogen thermal resistance studies on low-water activity foods (LWAF) use a variety of methods to inoculate food, as well as strategies to reduce water activity, which can influence thermal resistance observations. This study investigated effects of culture preparation method and osmolyte-induced water activity on thermal resistance of two Shiga toxin-producing Escherichia coli (STEC; O121:H19, O157:H7) challenged with isothermal conditions, determining D – and z -values for each isolate (56, 59, and 62 ° C). Tryptic Soy Broth (TSB) and Agar (lawn cultures) were compared. D -values of broth cultures were significantly and consistently larger than those of lawn cultures, and O121 was significantly more resistant than O157, but only at 56 ° C ( p < 0.05). To compare potential effects of water activity on STEC thermal resistance, cells were suspended in osmolyte solutions with varying water activity: high (TSB, a w 0.99), intermediate (61% glycerol or 26% NaCl, a w 0.75), and low (82% glycerol, a w 0.5). In most instances, STEC in high-water activity broth exhibited greater heat resistance compared to reduced-water activity solutions, except the glycerol intermediate-water activity solution (a w 0.75). Magnitudes varied with strain and temperature. The z -values of lawn cultures were significantly lower than those of broth cultures ( p < 0.05), but there were only some differences between high-a w and reduced-a w samples. There were no significant differences of z -values based on strain type. These results highlight that thermal resistance can be affected by culture preparation and that osmolyte-induced changes to water activity influence thermal inactivation of STEC by varying magnitudes. These results emphasize the challenges between extrapolating results from lab inactivation kinetic experiments to determine the inactivation of low water activity foods, especially those considered dry in nature.

Canada – Updated and Corrected Food Recall Warning – Provigo brand and Metro brand ground beef products recalled due to E. coli O157


Advisory details

Ottawa, September 28, 2020 – The food recall warning issued on September 27, 2020 has been updated to include additional product information. The food recall warning issued on September 27, 2020 has also been amended to correctly identify the affected products. The corrections for these products are marked by an asterisk (*). This additional information was identified during the Canadian Food Inspection Agency’s (CFIA) food safety investigation.

JBS Food Canada ULC is recalling raw, fresh, lean ground beef due to possible E. coli O157 contamination. This product was further processed by other companies into raw ground beef products. Consumers should not consume the recalled products described below.

The following products have been sold exclusively at Provigo Hull, 1 du Plateau, Gatineau, Quebec and Metro (Marché Kelly), 910 Maloney boulevard east, Gatineau, Quebec.

Recalled product

Brand Product Size UPC Codes
Provigo Medium ground beef club pack Variable Starts with
0 213026
All Best Before dates from 23.SE2020 up to and including 28.SE 2020 *
Provigo Medium ground beef Variable Starts with
0 214117
All Best Before dates from 23.SE2020 up to and including 28.SE 2020
Provigo Lean ground beef club pack Variable Starts with
0 217334
All Best Before dates from 23.SE2020 up to and including 28.SE 2020 *
Provigo Lean ground beef Variable Starts with
0 217331
All Best Before dates from 23.SE2020 up to and including 28.SE 2020
Metro Lean ground beef Variable Starts with
0 201020
All  « pkgd on » dates from 24.SE 2020 up to and including 26.SE 2020
Metro Lean ground beef fam. pack Variable Starts with
0 201710
All  « pkgd on » dates from 24.SE 2020 up to and including 26.SE 2020

What you should do

If you think you became sick from consuming a recalled product, call your doctor.

Check to see if you have the recalled products in your home. Recalled products should be thrown out or returned to the store where they were purchased.

Food contaminated with E. coli O157 may not look or smell spoiled but can still make you sick. Symptoms can include nausea, vomiting, mild to severe abdominal cramps and watery to bloody diarrhea. In severe cases of illness, some people may have seizures or strokes, need blood transfusions and kidney dialysis or live with permanent kidney damage. In severe cases of illness, people may die.


This recall was triggered by the company. The CFIA is conducting a food safety investigation, which may lead to the recall of other products. If other high-risk products are recalled, the CFIA will notify the public through updated Food Recall Warnings.

The CFIA is verifying that industry is removing the recalled products from the marketplace.


There have been no reported illnesses associated with the consumption of these products.

Product photos

Printer ready version of photos

  • Provigo - Medium ground beef club pack
  • Provigo - Medium ground beef
  • Provigo - Lean ground beef club pack
  • Provigo - Lean ground beef
  • Provigo - Lean ground beef - Nutrition facts
  • Provigo - Medium ground beef - Nutrition facts
  • Metro - Lean ground beef
  • Metro - Lean ground beef fam. pack

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