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Bacteria: an overview

Without bacteria, there would be no life on earth: simple as that. Bacteria are one of the world’s most abundant organisms, found in soil, water, food, air... and of course, the human body.

What are Bacteria?

Bacteria were the first living things to appear on Earth, about four billion years ago, making them some of the oldest known life forms on the planet.

Bacteria are single-celled microorganisms that are so small you need a microscope to see them. They are classified into 5 groups according to their basic shapes: spherical (cocci), rod (bacilli), spiral (spirilla), comma (vibrios) or corkscrew (spirochaetes). They can exist as single cells, in pairs, chains or clusters. Some look like sausages, some like footballs, other like strings of beads.

The bacteria found in Yakult are rod-shaped.


Where do I find bacteria?

Everywhere! Bacteria can be found in soil, in water, and on almost every surface around you. Some also live in or on other organisms including plants or animals – as well as us humans! Bacteria can live in the most unlikely and extreme of habitats from hot springs to the icy Artic, the desert, or even the deepest part of the ocean.

Blue Earth

Can I see bacteria?

Not without a microscope! Bacteria are single-celled microorganisms that are far too small to be seen by the human eye. Bacteria are measured in micrometres (µm). One µm is one-thousandth of a millimetre, or in other words 10,000 µm is 1 centimetre. Several hundred bacteria could comfortably sit on the full-stop at the end of this sentence.


How many bacteria are there in the world?

Lots! It would be almost impossible to measure exactly how many bacteria exist in the world, but one scientific paper has set an estimate at five nonillion (1030)1. That is: 5,000,000,000,000,000,000,000,000,000,000 bacteria
1 Whitman W, Coleman D, Wiebe W (1998). "Prokaryotes: the unseen majority"

How did it all begin...?

For millions of years, bacteria simply went about their work completely unseen. It was not until the late 17th century that they were officially 'discovered' by Dutch cloth merchant Antonie van Leeuwenhoek who developed a microscope capable of magnifying objects over 200 times.

Throughout the 20th century we found a lot more about bacteria; most notably that life wouldn’t exist without them and they are everywhere, and they have been for a very long time.

In the 21st century, microbiology is a growing field. We still need assistance from our microbial friends and research continues to explore new applications for bacteria. For instance, we hope they can help clean up some of the waste created by modern living, e.g. by breaking down plastic.

Scientific Evidence

More than one hundred peer-reviewed publications describe human studies with Yakult’s L. casei Shirota. In 2016, for example, there were over 20 peer-reviewed publications describing original research conducted by scientists in research institutes and hospitals in the UK, as well as the Netherlands, Belgium, Portugal, Mexico, Malaysia, Hong Kong, Singapore and Japan.

The research behind Yakult has led to the approval of health claims in nine countries;. In 1998 Yakult was one of the first products to be awarded the Food for Specified Health Use (FOSHU) status in Japan.

Fascinating Bacteria Facts!

Some bacteria can reproduce every 20 minutes in the right conditions.

In one night a single bacterium could produce one billion new bacteria.

Our bodies have at least as many bacterial cells as they do human cells. These are present on the surface of the skin and inside the mouth, nose and uro-genital tract, but the majority live within your digestive system – in fact, there are more bacteria in your large intestines than there are humans on this planet.

A teaspoon of soil contains more than 100 million live bacteria. If you could weigh the bacteria in an acre of farmland it would be as heavy as two cows!

Some bacteria are put into food on purpose. The bacteria change it to make different foods like fermented milk drinks. Yoghurt is made by mixing certain bacteria with milk. Other foods made using bacteria are cheese, salami, pickles and vinegar.

Bacteria have been revived from an Alaskan pond that had been frozen for 32,000 years, and examination of a 4.5 billion year old meteorite even found evidence of ancient bacteria on Mars!

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