Today, there are evidences that probiotic strains used as commercial bacteria are safe to use in applications. The safety of the probiotic products is appraised with the phenotypic and genotypic characteristics and the statistics of used microorganisms (Çakır 2003). Safety aspects of probiotic bacteria include the following requirements.
1. Strains for human use are preferred to be human origin.
2. They are isolated from healthy human gastrointestinal tract.
3. They have to be non-pathogenic.
4. They have to no history of relationship with diseases like, infective endocarditis or gastrointestinal tract disorders.
5. They do not DE conjugate bile salts.
6. They should not carry transmissible antibiotic resistance genes (Saarela, et al. 2000).
LACTIC ACID BACTERIA
Lactic acid bacteria (LAB) are ubiquitous microorganisms that can be beneficial in crop and livestock production. LAB refers to a large group of bacteria, rather than a single species or strain, that produce lactic acid as a by-product of digesting their food source (usually …show more content…
Some bacteriocins produced by lactic acid bacteria, such as nisin, inhibit not only closely related species but are also effective against food-borne pathogens and many other gram-positive spoilage microorganisms. For this reason, bacteriocins have attracted considerable interest for use as natural food preservatives in recent years (Rattanachaikunsopon et al., 2010). Since bacteriocins are isolated from foods such as meat and dairy products, which normally contain lactic acid bacteria, they have unknowingly been consumed for centuries. A study of 40 wide-type strains of Lactococcus lactic showed that 35 produced nisin. Nisin is the only bacteriocin with GRAS (Generally Regarded as Safe) status for use in specific