Probiotics defined

Under psycho-physical, dietary, and environmental stress conditions, or after medication intake, there is an imbalance of microflora that makes the body susceptible to attack by pathogens. A proper diet is one of the main factors that influence the qualitative and quantitative composition of intestinal microflora. The most common approach involves the consumption of traditional foods, such as yogurt and fermented milk, which essentially contain probiotics, defined as live microorganisms, which can positively affect the host by improving its intestinal microbial balance. 

Probiotics are defined as microbial preparations of living microorganisms having a positive effect on the intestinal flora after oral administration (R. Fuller, 1989). Bacterial cultures such as those derived from Lactobacillus acidophilus, Lactococcus lactis. Enterococcus faedum (see below). Bifidobacterium bifidum (see below), LactobadUus casd and Lactobacillus thermophilicum have proved reliable. 

The benefits of probiotics are often demonstrated under defined experimental laboratory conditions, but these beneficial effects fail to materialize in clinical trials, often because the trials are not properly controlled or consist of too few subjects. Large, double-blind, clinical trials are essential for establishing the practical and scientific logic of the probiotic concept. 

As defined by Wang, an ingredient can be classified as prebiotic if (1) it is resistant to the digestion in the upper gut tract, (2) it can be fermented by intestinal microbiota, (3) it brings beneficial effects to the host health, (4) it selectively stimulates the activity of probiotics, and (5) it is stable to food processing treatments. 

Probiotics are defined by the World Health Organization as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. This definition refers to non-pathogenic microorganisms present in foods or added to them, and excludes references to biotherapeutic agents and beneficial microorganisms not used in the food industry. ... 

Saulnier, D.M., Santos, E, Roos, S., Mistretta, T.-A. et al (2011) Exploring metabolic pathway reconstruction and genome-wide expression profiling in Lactobacillus reuteri to define functional probiotic features. PLoS One, 6, el8783. 

One of the early targets of probiotics has been the improvanent of the composition of the intestinal microbiota. From the above, it is obvious that criteria for improving intestinal microbiota composition are at present not clearly defined. Nevertheless, some options exist for improving intestinal microbiota. Keeping under control potential pathogens such as Clostridium difficile and Helicobacter pylori, which can be present in low numbers in the microbiota of asymptomatic healthy carriers, may be beneficial (see following text). Furthermore, although the composition of a healthy or normal microbiota is not known, it is assumed that the nuCTobiota a... 

Probiotic bacteria (probiotic was defined by Verschuere et al (2000) as a live microbial adjunct which has a beneficial effect on the host by modifying the host-associated or ambient microbial coimnunity, by ensuring improved use of feed or enhancing its nutritional value, by enhancing the host response towards disease, or by improving the quality of its ambient environment) added at the start of the first batch culture were still retrieved after four consecutive batches of three days each. This was the case when rotifers were fed either solely N. oculata, a yeast-based diet, a mixture of both feeds fed simultaneously or fed every other batch (Qi et al, 2009b). 

The functionality and therefore definition of a probiotic is largely dependent on the animal production system in which it will be used. Fuller s widely cited definition of a probiotic as a live microbial feed supplement which beneficially affects the host animal by improving its intestinal balance (Fuller, 1989) is too narrow for aquaculture production systems because aquatic animals are intimately associated with their ambient environment. Hence, microbial-induced improvements to the host ectobiota or host external environments may also be considered probiotic (Verschuere et al, 2000). In their review, Irianto and Austin (2002) defined an aquaculture probiont as an entire or component(s) of a microorganism that is beneficial to the health of the host . This all-encapsulating definition includes probiotic action on both internal and external environments, and introduces the prospect of microbial components, such as peptidoglycan and lipopoly-saccharides, acting as immunostimulants (Smith et aL, 2003). 

Lactic acid bacteria with defined functionalities play a major role as starter cultures for the production of fermented foods such as yogurt, cheese, bread or fermented drinks. Additionally, specific strains of lactic acid bacteria are also widely used as health promoting additives. These so-called probiotics are added to the food in hi cell numbers to enhance their functional properties or are marketed in isolated form as special dietary supplements. Probiotics are frequently distributed as dry powder. 

Two sequential FAO/WHO documents have defined "Probiotics" as "live microorganisms which, when consumed in adequate amounts, confer a health benefit on the host." This definition was provided by an expert committee which dealt with issues specifically related to probiotics in food the FAO/WHO experts stated emphatically that in their intentions the term probiotic was used exclusively to indicate beneficial bacteria consumed as a part of food, thus excluding any reference to bio-therapeutic agents. As a consequence, the 2001 document was directed to evaluate and to provide guidance on the administration of beneficial bacteria to... 

The amount of potentially probiotic bacteria which is to be ingested by consumers to receive the beneficial effect (the "effective dose" in contrast with the "infectious dose" of pathogenic bacteria) is not easily defined, as there is strong evidence that this could be a strain-specific feature, and that it also depends on the intended target effect, as well as host-related factors and those of the vector food. 

Third, a probiotic must be a taxonomically defined microbe or combination of microbes. The correct identification of the probiotic microorganism at the strain level is of paramount relevance, since it is fully acknowledged that the beneficial properties are strain-specific, and also to enable accurate post-marketing surveillance and epidemiological studies for safety/efficacy purposes. 

On the contrary, it seems extremely difficult to demonstrate the beneficial effect of probiotics administration to healthy adults, which are supposed to have a quite stable intestinal microbiota. We have to keep in mind that ecological niches such as the gut try to resist changes when they have reached homeostasis this attribute has been defined before as the "resilience" of the intestinal microbiota. 

Probiotics are live microorganisms usually consumed in the diet through fermented dairy foods and beverages. Fuller (1991) first defined probiotics as "live microbial food supplements that beneficially affect the host by improving the intestinal microbial balance." An updated definition was released in 2002 by the FAO/ WHO, which is the most current version "Probiotics are live microorganisms which, when administered in adequate amounts, confer a health benefit to the host." Several criteria must be met when a microorganism is proposed as a probiotic strain for human use ... 

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