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The microbiological world has a huge variety of fascinating fauna. These include protozoa and amoebas, bacteria, unicellular organisms and fungi, as well as very small multicellular organisms such as microscopic flatworms and nematodes. Each has its own biotope, diet, development and preferences. During this microsafari we will look for salient facts and trivia of three common microscopic organisms: Salmonella, Listeria and Escherichia coli.
Salmonella is a microorganism with quite a bit of resilience. It is named after Daniel Elmer Salmon, an American veterinarian whose assistant discovered the bacteria by pure chance in 1855.
Population Worldwide, some 93 800 000 Salmonella infections occur annually. The elderly, the sick, small children and pregnant women are especially susceptible to a splurge.
HabitatTheSalmonella lives primarily in the intestines of pigs and poultry, but can occur through them almost anywhere. Through unsanitary handling of food and drink, humans can also easily become carriers of this bacteria. Salmonella likes temperate climates and enjoys temperatures between 5 and 45°C most. Below 5°C, it becomes somewhat languid.
DietRawfulegg, raw meat, raw vegetables and fish are her big favorites. Salmonella is also found on certain fruits and fresh herbs or smoked salmon. Pretty varied, in other words.
ReproductionUndera temperature of 35 to 37°C, Salmonella can divide in 40 minutes.
This pathogenic boyfriend is a true survival specialist. It is named after its British discoverer, the surgeon Joseph Lister. Although reasonably unlikely to be infected, Listeria can cause the dangerous foodborne infection Listeriosis.
Population It is difficult to say how many Listeria bacteria are around. But roughly 1,600 people worldwide contract Listeriosis each year, of whom about 260 die. Most of these are vulnerable people or very young children.
Habitat The Listeria lives mainly in moist environments, such as stagnant water or decaying vegetation. It is a true winter animal and can withstand cold temperatures very well. That is why it is fine staying in the freezer for a few months.
Diet The Listeria loves frozen foods such as pre-packaged fish and meat. It also likes ready-to-eat products such as sandwiches and salads. However, young (mold) cheese and unpasteurized milk products are also a favorite. Pregnant women and babies should therefore avoid eating unpasteurized foods.
Reproduction At temperatures between 4 and 45°C, Listeria can divide as much as every 20 minutes.
This little fighter has an ambiguous reputation. E. coli lives in the intestines of humans and animals, where it protects its territory from other bacteria that can be harmful. Unfortunately, E. coli also sometimes ends up outside its territory, which can cause foodborne infections. She is therefore sometimes unflatteringly called the poop bacteria.
Population More than 265,000 infections with E. coli occur annually in the United States alone. It often causes nausea and diarrhea. The latter can cause dehydration, which is life-threatening if prolonged.
Habitat E. coli lives in the colon of a wide range of (mammalian) animals, including humans. Reduced personal hygiene plays well into the hands of E. coli.
Diet This cracker is common in raw vegetables. Especially if they have not been properly cleaned after fertilization or harvesting. Undercooked meats can also provide hiding places.
Reproduction E coli knows very well what it wants. At a temperature of 37°C, it multiplies every 24 minutes.
So much for our microsafari along these three quirky organisms. We hope it was an interesting journey. If you want to learn more about these organisms, we offer comprehensive (online) training. Think Microbiology and Controlling Contamination and Spoilage and Microbiology for the Food Industry. Want to know more? Contact us at learning@precongroup.com or call +31 (0)30 - 65 66 010!
Subscribe to our newsletter, our monthly look at food and non-food quality management.