Introduction
Microbial balance is critical for life. To maintain this and to have more health benefits various attempts has been made to modify the structure and metabolic activities of microbial community in intestine through modified foods, what termed as Probiotics which may help in restoring the natural healthy condition of body's internal environment, deteriorated by damaging food preparation, processing and preservation, excessive hygienic practices and modern approaches to nutrition, disease therapy and radiations.

Definition
"Probiotics" is the live microbial supplements conferring numerous health benefits to human or animals upon ingestion, by improving intestinal microbial balance.
"Prebiotic" is the nonabsorbable food components that beneficially stimulate one or group of the gut beneficial microbe groups.
"Synbiotics" is the term coined for the combined administration of specific prebiotics with probiotics that may improve therapeutic potential in the gastrointestinal tract by providing definite health benefits through synergistic action.

Note
The most commonly used Prebiotics are carbohydrate substrates (e.g. dietary fiber) with the ability to promote the components of the normal intestinal microflora which may evince a health benefits to the host viz. oligosaccharides, inulin, galactooligosaccharides and oligofructose are commonly used.

Probiotic microorganisms
The most widely used bacteria as Probiotics are the lactobacilli, and bi´Čüdobacteria but products incorporating other organisms such as Gram positive cocci, bacilli, yeasts and E. coli have also been applied. Certain strains of yeast (Saccharomyces cerevisae) and fungi (Aspergillus oryzae) are also included under Probiotics.

Concept of functional foods
Foods containing probiotic microorganisms come within the category of functional foods, i.e., foods, which have a positive effect on health. The global market for probiotic foods in the coming years is growing rapidly.

Probiotic functions
Following are given hereunder:
Increasing natural resistance against disease, prevent fungal overgrowth and some allergic reactions; improved resistance to toxic bowel problems and diarrhea; improving lactose intolerance conditions; reduction of cholesterol levels; and also act as antioxidants etc.

Conclusion:
Some factors viz. shelf life, effectiveness, safety and quality of probiotics is critically evaluated, as well as the benefits of foods are communicated to the consumers. More carefully controlled and large clinical trials are also essential for making the probiotics of wider acceptance. Advances in genetic engineering and biotechnology will make the probiotic to deliver the specific health benefits, in the improvements of effectiveness of already existing properties of strain. Funding for research must be increased for overall developments of Probiotics. There is need to develop an international criteria for safe use of probiotics.

About Author / Additional Info:
Gaurav Saxena
Babasaheb Bhimrao Ambedkar (Central) University, Lucknow
Email: gaurav10saxena@gmail.com