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A Look at Escherichia coli

Updated: Apr 16

By: Forward Food Solutions Team

Date Published: 4/15/21


Like the proverbial middle sister, pathogens won’t be ignored. Nor should they be.

Every year, thousands of people fall sick or are hospitalized due to pathogen caused illness. According to the CDC, E. coli (Escherichia coli), is responsible for 265,000 of these illnesses per year. Of this total, 3,600 people are hospitalized and 30 die. It is one of the top five causes of hospitalizations due to food borne illness each year. In this post we will take a closer look at E. coli (Escherichia coli).

What is it?

Escherichia coli is a bacterium found in human intestines. It can also be found in the intestines of animals, mostly cows, but also deer, chicken, pigs and sheep. All E. coli are not created equal. In fact, most strains are benign or even beneficial, aiding good bacteria in the gut, and even producing vitamins like K and B12.

There is a small group, however, that are pathogenic, causing gastroenteritis, urinary tract infections and even death in humans.

History

This bacterium was first discovered by Theodore Eschrerich in 1885. Escherich discovered it in the human colon and found that some strains caused infant diarrhea. It wasn’t recognized as a pathogen until 1982, when an outbreak occurred due to undercooked hamburgers eaten from a fast-food chain in Oregon and Michigan. At that time, scientists found that an especially rare, virulent strain, 0157-H7 was the cause. Until then, 0157-H7 had only been seen once, in1975, and had never been linked to an outbreak.

STEC

The group of Escherichia coli most dangerous to humans are those that produce Shiga-toxin. Shiga toxin is one of the most harmful toxins to humans. Shiga toxin producing E. coli (STEC) are able to do something that non STEC are not. Non STEC E. coli remain on the surfaces of the large intestine, whereas Shiga toxin producing are able to attach and eventually be absorbed into the intestinal wall making it systemic? Once it is able to travel, these bacteria move throughout the body wreaking havoc. According to the CDC, “An estimated 265,000 STEC infections occur each year in the United States.

Escherichia coli 0157-H7 Of the STEC strains, 0157-H7 causes the most infections, about 36 %. 0157-H7 has characteristics that make it uniquely dangerous to humans.

  • Easy Transmission Compared to other STEC, 0157-H7 can be spread with as few as 20 organisms present. It can be transmitted easily with person to person contact, contact with contaminated surfaces and ingestion of contaminated food and water.

  • Hard to Kill- 0157-H7 is notoriously difficult to kill compared to other E. coli. It can survive in highly acidic conditions.

  • Heat and Cold Tolerance: 0157-H7 can survive at temperatures as low as 7°C and as high as 50°C.

  • Long Life: This bacteria has been shown to survive up to 21 days on untreated meat.

  • It is Evolving: Escherica coli 0157-H7 has been found to be evolving making it increasingly resilient. Genetic tests have found that ancestors of 0157-H7 have been around for over 175 years. Interestingly, they found that it also began “acquiring” another form of Shiga toxin, Stx2a, around 60 years ago. Some of the most recent infections have only had Stx2a. It is clear that attention must be paid to the continuing evolution of this pathogen in order to stay a step ahead of it.

As we have learned, there are many factors that make Escherichia coli a particularly dangerous and difficult adversary in the war against food related illness. Companies must have a thorough understanding of the risks associated with the foods they produce and the pathogens that threaten them. In future posts we will dig deeper into Escherichia coli and look at what can be done to mitigate the risks associated with this dangerous pathogen to better keep food safe from Farm to Fork.


Want to learn more:

References:

https://www.cdc.gov/features/ecoliinfection/

https://wwwnc.cdc.gov/eid/article/17/1/p1-1101-t3

https://www.nejm.org/doi/full/10.1056/NEJM198303243081203

https://www.cdc.gov/ecoli/general/index.html

https://www.tandfonline.com/doi/pdf/10.4161/viru.2.6.18423

https://www.sciencedaily.com/releases/2015/09/150922115635.htm

Photo credit: fda.gov


Keywords:

Forward Food Solutions, Food Safety Consulting, Escherichia coli, E. coli 0157:H7, STEC, Shiga toxin, Transmission, Temperature Tolerance


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