Probiotic microorganisms are defined as living microorganisms that provide health benefits on the host when administered in adequate amounts. The benefits include improvement of microbial balance immune system and oral health, provision of cholesterol-lowering effect, and antimicrobial activity against a wide variety of bacteria and some fungi. Kefir microbiota contains active living microorganisms. Many researches were carried out that potential probiotic bacteria such as Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus kefir, Lactobacillus kefiranofaciens, Leuconostoc mesenteroides, or yeasts like microorganisms such as Saccharomyces cerevisiae, Kluyveromyces lactis, and Kluyveromyces marxianus were isolated from kefir grains. This chapter presents the data both on the probiotic bacteria isolated from kefir grains or kefir and the probiotic properties of kefir produced with these microorganisms.
TopProbiotic Microorganisms
Probiotic microorganisms are live microorganisms that provide a benefit on the human health. The term “probiotic” means “for life” in Greek and first used in 1965 to explain secretions of a microorganism that stimulate the growth of other microorganism by Lilly and Stillwell (Lee, 2009). In 1974, it was understood that there was a relationship between probiotics and host system. In addition, probiotics are described as “organisms and substances with beneficial effects for animals by influencing the intestinal microbiota”. Finally, probiotics are defined as “living microorganisms which upon ingested in adequate amounts provide health benefits beyond inherent general nutrition” by FAO/WHO (FAO/WHO, 2006).
Fermented dairy products are the most common foods containing probiotics. Among them yoghurt is the leading (Brown & Valiere, 2004). In 1907, it was first stated that bacteria in the intestines had a positive effect on human health. Lactobacillus delbrueckii subsp. bulgaricus which is a yoghurt bacteria, was determined to be responsible for a longer life and better health conditions (Brown & Valiere, 2004). In 1935, positive effect of Lactobacillus acidophilus on human health was shown by Retteger, Levy, Weinstein, & Weiss (1935). After that date, many microorganisms such as Bifidobacterium, Streptococcus, Enterococcus and Lactococcus have been identified as probiotic by different researches (Goldin, 2011).
In order for a microorganism to be evaluated as a probiotic, it must have certain criteria:
- •
Having a proven beneficial effect on human health,
- •
Being non-pathogenic and non-toxic,
- •
Maintaining the stability in the product,
- •
Containing an appropriate number of viable cells,
- •
Surviving in the gastrointestinal system,
- •
Having acceptable sensory properties.
TopHealth Effects Of Probiotic Microorganisms
Many studies were performed about the health effects of probiotic microorganisms. Some of these effects are listed below: