Category Archives: E.coli O157

Research – Thermal Resistance of Foodborne Pathogens and Enterococcus faecium NRRL B-2354 on Inoculated Pistachios



Process control validations require knowledge of the resistance of the pathogen(s) of concern to the target treatment and, in some cases, the relative resistance of surrogate organisms. Selected strains of Escherichia coli O157:H7 (five strains), Listeria monocytogenes (five strains), and Salmonella enterica (five strains) as well as Salmonella Enteritidis phage type (PT) 30 and nonpathogenic Enterococcus faecium NRRL B-2354 were inoculated separately (as individual strains) onto inshell pistachios. The thermal tolerance of each strain was compared via treatment of inoculated pistachios to hot oil (121°C) or hot water (80°C) for 1 min. Survivor curves in hot oil or hot water (0.5 to 6 min, n = 6 to 15) were determined for one or two of the most resistant strains of each pathogen, as well as E. faecium NRRL B-2354 and Salmonella Enteritidis PT 30, and the Weibull model was fit to the data. A pilot-scale air-impingement oven was used to compare the thermal tolerance of E. faecium NRRL B-2354 and Salmonella Enteritidis PT 30 on pistachios with or without a brining pretreatment and at either dry (no steam) or 30% humidity (v/v) oven conditions. No significant difference in the time to a 4-log reduction in hot oil or hot water was predicted for any of the strains evaluated, on the basis of the 95% confidence interval. In the pilot-scale oven, E. faecium NRRL B-2354 was more thermally resistant than Salmonella in a broad set of differing treatments, treatment times, and temperatures. Salmonella is a suitable target pathogen of concern in pistachios for thermal processes because no other pathogen tested was more thermally resistant under the conditions evaluated. E. faecium NRRL B-2354 was at least as thermally resistant as Salmonella under all conditions evaluated, making it a good potential surrogate for Salmonella on pistachios.

  • Salmonella Enteritidis PT 30 is a reasonable target strain for laboratory-based studies.
  • E. coli O157:H7 or L. monocytogenes were less thermally resistant than Salmonella.
  • E. faecium NRRL B-2354 was at least as thermally resistant or more so than Salmonella.
  • E. faecium NRRL B-2354 is a good potential thermal-treatment surrogate for pistachios.

Research – Fate of Salmonella enterica and Enterohemorrhagic Escherichia coli on Vegetable Seeds Contaminated by Direct Contact with Artificially Inoculated Soil during Germination



Contaminated vegetable seeds have been identified as a potential source of foodborne bacterial pathogens. This study was undertaken to observe the behavior of Salmonella and enterohemorrhagic Escherichia coli (EHEC) on vegetable seeds, contaminated by direct contact with artificially inoculated soil, during germination. Sterile sandy soil inoculated with lyophilized cells of four individual strains of Salmonella or EHEC (three O157:H7 strains and one O104:H4 strain) was mixed with sanitized seeds (2 g) of alfalfa, fenugreek, lettuce, and tomato at 20°C for 1 h. The contaminated seeds were germinated on 1% water agar at 25°C for 9 days in the dark. Populations of Salmonella and EHEC on various tissues (seed coat, root, cotyledon, and stem, etc.) of sprouts and seedlings were determined every other day over the germination period. Overall, 70.4 and 72.4% of collected tissue samples (n = 544) tested positive for Salmonella and EHEC, respectively. In general, the mean populations of Salmonella and EHEC on sprout and seedling tissues increased with the prolongation of germination time. Seed coats had the highest bacterial counts (4.00 to 4.06 log CFU/0.01 g), followed by the root (3.36 to 3.38 log CFU/0.01 g), cotyledon (3.13 to 3.38 log CFU/0.01 g), and stem tissues (2.67 to 2.84 log CFU/0.01 g). On average, tissue sections of fenugreek sprouts and lettuce seedlings had significantly higher (P < 0.05) numbers of Salmonella and EHEC cells than that of alfalfa sprouts and tomato seedlings. Data suggest that the growth and dissemination of Salmonella and EHEC cells on alfalfa, fenugreek, lettuce, and tomato sprout and seedling tissues are influenced by the type of vegetable seeds and sprout and seedling tissues involved. The study provides useful information on the fate of two important foodborne bacterial pathogens on selected vegetable seeds, contaminated by direct contact with inoculated soil, during the germination process.

  • Vegetable seeds were contaminated via contact with pathogen-bearing sandy soil.
  • Pathogens on contaminated seeds were recovered from tissues of sprouts and seedlings.
  • Tomato and alfalfa tissues had lower pathogen counts than fenugreek and lettuce tissues.
  • Seed coats had higher pathogen counts than the root and cotyledon tissues.
  • Stem tissues had lower Salmonella/EHEC counts compared with all other tissues.

Canada – Food Recall Warning (E. coli O157:H7) – Certain sweetened dried cranberries

Food Poisoning News

Recall date:
June 19, 2020
Purpose for recall:
Microbiological – E. coli O157:H7
Hazard classification:
Class 1
Firm / Agency:
Les Aliments Johnvince
Extent of the distribution:

Recall particulars

Ottawa, June 19, 2020 – Les Aliments Johnvince is recalling sure sweetened dried cranberries from {the marketplace} as a consequence of potential E. coli O157:H7 contamination. Customers mustn’t eat the recalled product described under.

Recalled product

Model Product Dimension UPC Codes Extra data
None Sweetened dried cranberries
PLU 5176
Variable weights (plastic bag of roughly 300 g) None 06472
This packaged product might have been bought with or with out codes from Might 28, 2020 as much as and together with June 8, 2020. Customers who’re uncertain if they’ve bought the affected product are suggested to contact their retailer.

What it is best to do

When you suppose you turned sick from consuming a recalled product, name your physician.

Verify to see you probably have the recalled product in your house. Recalled merchandise needs to be thrown out or returned to the shop the place they have been bought.

Meals contaminated with E. coli O157:H7 might not look or odor spoiled however can nonetheless make you sick. Signs can embrace nausea, vomiting, gentle to extreme belly cramps and watery to bloody diarrhea. In extreme circumstances of sickness, some folks might have seizures or strokes, want blood transfusions and kidney dialysis or stay with everlasting kidney injury. In extreme circumstances of sickness, folks might die.


This recall was triggered by the corporate. The Canadian Meals Inspection Company (CFIA) is conducting a meals security investigation, which can result in the recall of different merchandise. If different high-risk merchandise are recalled, the CFIA will notify the general public by way of up to date Meals Recall Warnings.

The CFIA is verifying that business is eradicating the recalled product from {the marketplace}.

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Research – Prevalence of Shiga Toxin-Producing Escherichia Coli in Beef Cattle


A large number of Shiga toxin-producing Escherichia coli (STEC) strains have caused major outbreaks and sporadic cases of human illnesses, including mild diarrhea, bloody diarrhea, hemorrhagic colitis, and the life-threatening hemolytic uremic syndrome. These illnesses have been traced to both O157 and non-O157 STEC. In a large number of STEC-associated outbreaks, the infections were attributed to consumption of ground beef or other beef products contaminated with cattle feces. Thus, beef cattle are considered reservoirs of STEC and can pose significant health risks to humans. The global nature of the human food supply suggests that safety concerns with beef will continue and the challenges facing the beef industry will increase at the production and processing levels. To be prepared to address these concerns and challenges, it is critical to assess the role of beef cattle in human STEC infections. In this review, published reports on STEC in beef cattle were evaluated to achieve the following specific objectives: (i) assess the prevalence of STEC in beef cattle, and (ii) determine the potential health risks of STEC strains from beef cattle. The latter objective is critically important because many beef STEC isolates are highly virulent. Global testing of beef cattle feces revealed wide ranges of prevalence rates for O157 STEC (i.e., 0.2 to 27.8%) and non-O157 STEC (i.e., 2.1 to 70.1%). Of the 261 STEC serotypes found in beef cattle, 44 cause hemolytic uremic syndrome and 37 cause other illnesses.

USA – David B’s Custom Meats recalls ground beef after E. coli illness and positive test – STEC E.coli

Food Poison Journal

The Illinois Department of Agriculture (IDOA) is issuing a public health alert due to an undetermined amount of ground beef product prepared under custom exemption that may be contaminated with Non-O157 Shiga toxin E. coli (STEC), a bacteria commonly known as “E. coli”. That product was prepared at a Type II Establishment (custom exempt), David B’s Custom Meats, located in Carlinville Illinois, in Macoupin County at the beginning of 2020 to current. Custom exempt meat products are not inspected and cannot be offered for sale; because of this, a recall of the affected product was not requested.

The problem was discovered when a resident of Macoupin County notified local public health officials about sickness after consuming ground beef. The sample collected from the remaining product tested positive for presence of NON-O157 Shiga toxin-producing E.coli.

USA – 43 Thousand Pounds of Hamburger recalled over E. coli O157

Food Poison Journal

Lakeside Refrigerated Services, a Swedesboro, N.J. establishment, is recalling approximately 42,922 pounds of ground beef products that may be contaminated with E. coli O157:H7, the U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS) announced today.

The raw ground beef items were produced on June 1, 2020.

USA -USDA Will Expand non-O157 STEC Testing to Ground Beef

Food Poisoning Bulletin

According to an announcement in the Federal Register, the USDA will expand non-O157 STEC (Shiga toxin-producing E. coli) testing to ground beef, bench trim, and other raw ground beef components. The non-O157 strains include what’s called the “Big Six” E. coli strains: E. coli O26, O45, O103, O111, O121, and O145.

Research – Essential Oils: Their Antibacterial Properties and Potential Applications in Foods–A Review

Pub Med


In vitro studies have demonstrated antibacterial activity of essential oils (EOs) against Listeria monocytogenes, Salmonella typhimurium, Escherichia coli O157:H7, Shigella dysenteria, Bacillus cereus and Staphylococcus aureus at levels between 0.2 and 10 microl ml(-1). Gram-negative organisms are slightly less susceptible than gram-positive bacteria. A number of EO components has been identified as effective antibacterials, e.g. carvacrol, thymol, eugenol, perillaldehyde, cinnamaldehyde and cinnamic acid, having minimum inhibitory concentrations (MICs) of 0.05-5 microl ml(-1) in vitro. A higher concentration is needed to achieve the same effect in foods. Studies with fresh meat, meat products, fish, milk, dairy products, vegetables, fruit and cooked rice have shown that the concentration needed to achieve a significant antibacterial effect is around 0.5-20 microl g(-1) in foods and about 0.1-10 microl ml(-1) in solutions for washing fruit and vegetables. EOs comprise a large number of components and it is likely that their mode of action involves several targets in the bacterial cell. The hydrophobicity of EOs enables them to partition in the lipids of the cell membrane and mitochondria, rendering them permeable and leading to leakage of cell contents. Physical conditions that improve the action of EOs are low pH, low temperature and low oxygen levels. Synergism has been observed between carvacrol and its precursor p-cymene and between cinnamaldehyde and eugenol. Synergy between EO components and mild preservation methods has also been observed. Some EO components are legally registered flavourings in the EU and the USA. Undesirable organoleptic effects can be limited by careful selection of EOs according to the type of food.

USA – FDA Releases Report on Investigation into Fall 2019 Outbreaks of Illnesses Tied to Romaine Lettuce



As the nation grapples with the COVID-19 public health emergency, the U.S. Food and Drug Administration is grateful for all that the food and agricultural sector is doing to provide safe and available food to consumers during this difficult time. As we work to get through the current challenge together, the FDA remains committed to protecting both the safety of workers and consumers from foodborne illness as we strive to ensure that America’s food supply remains resilient and among the safest in the world. As part of our ongoing efforts to combat foodborne illness, the FDA released the findings of an investigation into three outbreaks of E. coli O157:H7 illnesses that occurred in Fall 2019, all tied to romaine lettuce, that suggests the proximity of cattle to produce fields may have been a contributing factor.

Investigational Findings

The FDA worked with the Centers for Disease Control and Prevention (CDC) and state partners to investigate the contamination of romaine lettuce with several strains of E. coli O157:H7 that caused three outbreaks of foodborne illness beginning in September 2019 and which were declared over in January 2020. Some clusters (but not all) within each of these outbreaks were traced back to a common grower with multiple ranches/fields located in the Salinas, CA, growing region. Together, the outbreaks made 188 people ill.

During the course of on-farm investigations, one of the outbreak strains of E. coli O157:H7 was detected in a sample on public land less than two miles upslope from a produce farm with multiple fields that were identified during the traceback investigations. Other Shiga toxin-producing strains of E. coli (STEC) were found in closer proximity to where romaine lettuce crops were grown, including two samples from the border area of a farm immediately next to cattle grazing land in the hills above leafy greens fields and two samples from on-farm water drainage basins.

While these strains were not tied to the outbreaks, they do offer insight into the survival and movement of pathogens in this growing region. These findings, together with the findings from earlier leafy greens outbreaks, suggest that a potential contributing factor has been the proximity of cattle to the produce fields identified in traceback investigations. This is especially true when cattle are adjacent to and at higher elevations than produce fields.

In the report, “Investigation Report: Factors Potentially Contributing to the Contamination of Romaine Lettuce Implicated in the Three Outbreaks of E. coli O157:H7 During the Fall of 2019,” we’re calling on leafy greens growers to assess and mitigate risks associated with adjacent and nearby land uses, including grazing lands and animal operations. Of note, the number of cattle observed on nearby lands during the 2019 investigations was far lower than the volume of a large Concentrated Animal Feeding Operation, offering a useful reminder that high-density animal operations are not the only factor to consider. These key findings reinforce our concern about the possible impact of nearby and adjacent land use on the safety of leafy green crops and further underscore the importance of reviewing current operations and implementing appropriate risk mitigation strategies.

Research – Antibacterial activity and mechanism of Litsea cubeba essential oil against food contamination by Escherichia coli and Salmonella enterica

Wiley Online

Litsea cubeba essential oil (LC‐EO) has been reported as antibacterial agents, but there are few studies about its possible antibacterial mechanism. The antibacterial activities and the underlying mechanisms of LC‐EO against Escherichia coli O157: H7 and Salmonella enterica were investigated. The results showed that the LC‐EO was more effective against gram‐negative bacteria. The inhibition zone for E. coli O157: H7 and S. enterica were 3.1 ± 0.8 and 4.5 ± 0.6 mm, respectively. The minimum inhibitory concentration of LC‐EO against both bacteria was 0.9 μg/ml, while the minimum bactericidal concentrations were 4.5 and 9 μg/ml. Gas chromatography–mass spectrometry analysis confirmed that citral (86.8%) was the main component of LC‐EO. The results of a time–kill analysis illustrated that treatment with LC‐EO led to a rapid decrease in viable bacterial cell number. The release of electrolytes and nucleic acids from the bacterial cells increased with the dose of LC‐EO. Propidium iodide uptake revealed that LC‐EO caused cell membrane damage. Scanning electron and transmission electron microscopy showed that LC‐EO caused damage to the cell walls and membranes, resulting in cell deformation, atrophy, and large central voids. Thus, LC‐EO may provide the basis for the development of new natural food preservatives.