Is Spain to blame, is Germany responsible for the germ, is it tomatoes, cucumbers or beansprouts??
Fingers are being pointed in all directions but the source has still to be discovered.
The source? That’s simple, it is us and other animals, not salad vegetables. Escherichia coli are symbiotic bacteria present in all human colons. They, along with up to 1 kilogram of other “friendly bacteria”, help us to digest our food. In fact many of the bacteria present in our large intestine provide us with additional vitamins that they synthesise. E coli in particular synthesises Vitamin K, a blood clotting factor. Without E coli present it would take a lot longer for our wounds to heal.
However, this friendly bacterial family soon become pathogens as soon as they are excreted with our faeces. They mutate quite quickly into several serotypes or variants, one of which is 0157, which first hit the headlines in the early 1980s in an undercooked beefburger.
Bacteria have evolved with us over hundreds of thousands of years. The majority are harmless. We rely on some to provide oxygen, to use as a source of human insulin, to digest oil spills, to compost material, to provide antibiotics, to make vaccinations, etc, etc. Yes they are used extensively in biotechnology.
It is only the minority that evolve into pathogens, and they only do this to protect themselves in a particular environment.
This new variant of E coli is particularly virulent by releasing a poison which destroys red blood cells, which block the kidneys and cause dialysis and eventually death if not treated quickly. However, the elderly, young, ill people and immunocompromised are more at threat due to a weakened immune system.
We are a source of generic E coli, cattle harbour the 0157 variant. As our and cattle’s faeces end up in water courses and/or on soil, the bacteria will remain there. Cucumbers and tomatoes do not grow directly in soil, it is only the roots of the plants that are in contact with the soil. The bacteria are unable to cross the many membranes of the plants’ roots. The only way that the bacteria are transferred to these salads are by human hands.
Yes, it looks highly probable that we have another Typhoid Mary, or should I say E coli Jane/John Doe (as we do not know their name yet) as the source of this deadly bacterial strain.
I always stress in my training courses that you must wash salad vegetables and fruit well before eating, as they are likely to be picked by humans who have a poor knowledge of hygiene, especially washing hands after going to the toilet. There are very few toilet facilities on the large fruit/salad farms, so the only place to go if they are suddenly taken short is in the field. E coli in faecal contamination on hands quickly develop into pathogens, in particular low dose pathogens. Ingestion of just a few bacteria cells will cause illness.
