Category Archives: E.coli O157:H7

Research – Novel Continuous and Manual Sampling Methods for Beef Trim Microbiological Testing

Journal of Food Protection

A sampling method that represents a greater proportion of the beef trimmings in a 900-kg combo bin should improve the current pathogen sampling and detection programs used by fresh beef processors. This study compared two novel, nondestructive sampling methodologies (a continuous sampling device [CSD] and a manual sampling device [MSD]) with the current industry methodologies, the N60 Excision (the “gold standard”) and N60 Plus, for collection of trim samples. Depending on the experiment, samples were analyzed for naturally occurring Escherichia coli O157:H7 or Salmonella, inoculated surrogates, or indicator organisms in multiple plants, on multiple days, across multiple lean percentage mixtures. Experiments 1A and 1B with natural contamination found no E. coli O157:H7 but similar (P > 0.05) prevalence of Salmonella (CSD 9.2% versus N60 Excision 6.0%) and similar (P > 0.05) levels of indicator organisms for CSD compared with both N60 methodologies. In experiments 2 and 3, CSD cloth sampling had the same or higher prevalence of naturally occurring E. coli O157:H7 and E. coli O157:H7 surrogate organisms, as well as similar levels of indicator organisms compared with the N60 methodologies. In experiment 4, MSD cloth sampling detected similar (P > 0.05) prevalence of E. coli O157:H7 surrogate organisms, as well as slightly lower (P < 0.05) levels of indicator organisms compared with N60 Plus. In experiment 5, the MSD found similar (P > 0.05) prevalence of naturally occurring E. coli O157:H7 and the same or slightly higher (P < 0.05) levels of naturally occurring indicator organisms compared with N60 Plus. In experiment 6, the MSD detected the same (P > 0.05) prevalence of naturally occurring Salmonella as did N60 Excision. The results of these experiments collectively demonstrate that sampling beef trim using either the CSD or MSD provides organism recovery that is similar to or better than the N60 Excision or the N60 Plus methodologies.

Research – USA – Microbiological Testing Program for Escherichia coli O157:H7 and non-O157 Shiga toxin-producing Escherichia coli (STEC)


FSIS considers raw, non-intact beef products or the components of these products found to have six Shiga toxin-producing Escherichia coli (STEC) to be adulterated, in addition to E. coli O157:H7. (Refer to the Federal Register notice Shiga Toxin-Producing Escherichia coli in Certain Raw Beef Products | PDF). These six non-O157 STECs are O26, O45, O103, O111, O121, and O145.

On June 4, 2012, FSIS began verification testing for these non-O157 STEC in domestic and imported beef manufacturing trimmings from cattle slaughtered on or after June 4, 2012. Beef manufacturing trimmings collected from cattle slaughtered before June 4, 2012, or that contain other components such as cheek meat are analyzed for E. coli O157:H7 only.

USA – Cargill recalls 12.64 tons of ground beef for E. coli O157:H7 contamination

Food Safety News 

kswfoodworld E.coli O157

Image CDC


Cargill Meat Solutions in Fort Morgan, CO late Thursday recalled approximately 25,288 pounds of ground beef products that may be contaminated with E. coli O157: H7, according to the U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS).

The ground beef items were produced on Aug. 16, 2018. The following products are subject to recall:

  • 10-lb. chubs of “EXCEL 93/7 FINE GRIND GROUND BEEF” with “Use/Frz. By Sep 05” on the chub label and a “PACK DATE 08/16/2018” on the box label.

The recalled beef products bear the establishment number “EST. 86R” inside the USDA mark of inspection. These items were shipped to warehouses in California and Colorado.

The problem was discovered on Aug. 22 by the establishment when they reviewed their records and determined that the product may be associated with the product that was presumptive positive for E. coli O157: H7. The company then notified FSIS. There have been no confirmed reports of adverse reactions due to consumption of these products.

USA -FDA Investigating Multistate Outbreak of E. coli O157:H7 Infections Linked to Romaine Lettuce from Yuma Growing Region




On July 31 and August 1, 2018, the FDA participated in a meeting of the Leafy Greens Food Safety Task Force that was formed in response to the serious outbreak of E. coli O157:H7 associated with romaine lettuce that occurred earlier this year. During the meeting FDA shared preliminary hypotheses from the Environmental Assessment in Yuma to facilitate conversations with state and local officials, industry and local growers on the hypotheses and associated actions necessary to prevent such an outbreak from occurring again.

As FDA has previously stated, samples of canal water have tested positive for the outbreak strain of E. coli. FDA continues to consider that contaminated water coming into contact with produce, either through direct irrigation or other means, is a viable explanation for the pattern of contamination. But other hypotheses were discussed as well. FDA notes that the canal is close to a Concentrated Animal Feeding Operation (CAFO), a facility with a large number of cattle on the premises. The CAFO can hold in excess of 100,000 head of cattle at any one time and the FDA traceback information showed a clustering of romaine lettuce farms nearby.

Our experts continue to work on examining potential links between the CAFO, adjacent water, and geologic and other factors that may explain the contamination and its relationship to the outbreak. Additional sampling activities will be conducted to further explore and narrow down hypotheses in the near future. Our findings will be detailed in a finalized environmental assessment report.

We urge other government and non-government entities, produce growers in the region, and those engaged in managing the canal systems to work with FDA and marshal and deploy resources to achieve our collective food safety goal. Broad engagement from the surrounding community is critical to developing and implementing remediation measures to reduce the potential for another outbreak. We believe local in-depth knowledge and actions are critical in helping resolve this issue in order to protect public health.

The Environmental Assessment report will be made publicly available when complete.

Rsearch – Food residuals on the food‐contacting surfaces of stainless steel and polypropylene influence the efficacy of ultraviolet light in killing foodborne pathogens

Wiley Online


This study was conducted to examine effects of food residues on the survivals of pathogens on stainless steel (SSS) and polypropylene (PPP) after ultraviolet‐radiation (UVR) surface decontamination. Cultures of Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, Staphylococcus aureus, and Listeria monocytogenes were inoculated on coupons containing deionized water, tryptic soy broth, pork, chicken, cabbage, and milk, respectively. The surface coupons were incubated at 100% relative humidity (RH) and 25°C for 24 hr to produce their own biofilms. UVR (=254 nm) surface decontamination for 120 min resulted in bacterial reductions in the levels of ≥2.5 log10 cfu/coupon. Populations of S. Typhimurium and L. monocytogenes within biofilms declined on SSS harboring chicken juice after UVR for 120 min, showing by <1.5 log10‐reductions. The presence of food residues on the food‐contacting surfaces would facilitate the strong adhesion of these organisms, indicating that bacteria enclosed in biofilms were more resistant to UVR sanitization.

Practical applications

In this study, it seemed to indicate that the incidence of varying food residues such as deionized water, tryptic soy broth, pork, chicken, cabbage, and milk could affect bacterial adhesion–attachment to the food‐contacting surfaces significantly. At least, some food residues such as pork, chicken, and milk would be supposed to provide a favorable environment where major foodborne pathogens are able to grow and produce their biofilms strongly. Especially, it was determined that the gram‐negative bacteria such as Escherichia coli O157:H7 and Salmonella typhimurium showed the higher sensitivity on coupons against ultraviolet‐radiation surface decontamination.

UK -Analysis shows source of E. coli outbreak was leafy greens – O157 – 2016

Food Safety News 

CDC E.coli

Image CDC Enter a caption

Increased use of ingredient-based analyses is being promoted by researchers after the method was used to identify the source of infection in an E. coli outbreak. 

Public Health England was alerted to an outbreak of Shiga toxin-producing E. coli (STEC) O157 phage type (PT) 34 in July 2016 involving 56 cases in England and Wales. The source of infection was baby-mixed leaf salad, which was an ingredient in multiple dishes.

“A traditional analysis may have resulted in multiple menu items being associated with illness, thereby failing to identify the true source of infection,” said researchers.


Research – Association of Escherichia coli O157:H7 with Houseflies on a Cattle Farm

American Society of Microbiology fly

The ecology of Escherichia coli O157:H7 is not well understood. The aims of this study were to determine the prevalence of and characterize E. coli O157:H7 associated with houseflies (HF). Musca domestica L. HF (n = 3,440) were collected from two sites on a cattle farm over a 4-month period and processed individually for E. coli O157:H7 isolation and quantification. The prevalence of E. coli O157:H7 was 2.9 and 1.4% in HF collected from feed bunks and a cattle feed storage shed, respectively. E. coli O157:H7 counts ranged from 3.0 × 101 to 1.5 × 105 CFU among the positive HF. PCR analysis of the E. coli O157:H7 isolates revealed that 90.4, 99.2, 99.2, and 100% of them (n = 125) possessed the stx1, stx2, eaeA, and fliC genes, respectively. Large populations of HF on cattle farms may play a role in the dissemination of E. coli O157:H7 among animals and to the surrounding environment.