**1. Probiotics: small creatures that do big things**

Bacteria are often associated with diseases or with something that is frightening and disgusting. But along with advances in technology, bacteria today are not considered only as an enemy but can also be friends. Basically bacteria are microorganisms that is part of nature that are found almost everywhere on the earth's surface, atmosphere, also the upper atmosphere [1–3]. The shape is very small, cannot be seen by the eye but its existence is very important to maintain environmental balance. Microorganisms are usually considered to include all prokaryotes, protists and microalgae. Fungi, especially those that are small and do not form hyphae, can also be considered as a part of it, although many do not agree. Most people assume that what can be considered microorganisms are all very small organisms that can be bred in petri dishes or incubators in the laboratory and capable of reproducing themselves by mitosis [4].

Collection of beneficial microbes known as probiotics, a word derived from the Greek word that means for life. Among the researchers there were slight differences of opinion regarding what could be called probiotics, including:

• Probiotics are compounds produced by a microorganism that can stimulate the growth of other microorganisms, so it is the opposite of antibiotics [5].


Probiotics can be found in several products depending on the intended use. They can be marketed as food, medical food, food supplements or medicine. In general, probiotics are marketed as food supplements e.g. pill/tablet products or as food items, e.g., Yogurt, Kefir. Some probiotic organisms including *Lactobacillus* sp., *Streptococcus* sp., and *Bifidobacterium* sp. have been "generally recognized as safe" status, which means that they are additives that are permitted in food substances. The term probiotic was originally intended as a supplement used to improve or prolong human life or health by providing a sufficient amount of good microorganisms into the body through food. Having recognized the positive benefits of probiotics on human health, many practitioners and researchers have begun to try and apply probiotics to livestock, agriculture, and fisheries.
