**2.4 Test model of** *C. albicans***-infecting mouse to determine the effects of** *L. casei* **in vaginal candidiasis**

In the test model of *C. albicans*-infecting mouse, Liao et al. [60] analyzed the effects of *L. casei* administration in vaginal candidiasis. The animals were inoculated with *L. casei* vaginally throughout 7 days for prophylactic testing. Three mice were killed, and the amount in CFU/ml was measured. The animals had *C. albicans* infected the vaginal cavity 2 days after the infection. The animals were treated with *C. albicans* in therapeutic tests and after 2 days, *L. casesi* was infected for 5 days. The CFU/ml number was then measured in vaginal samples. The findings suggest that prophylactic *L. casei* treatment might enhance vaginal mucosal immunity, increasing IL-17 production during infection. IL-23 levels had also weaker anti-inflammatory effects than those in the control group. In the therapy group, after 5 days of treatment, *L. casei* decreased the fungal vaginal load.

#### **2.5 Probiotics and its advantageous effects on skin**

Mottin and Suyenaga [61] described that poor skin problems might impact the quality of life of the patient due to discomfort. Human skin is made up of several fungus and symbiotic bacteria Chronic skin diseases that require lengthy treatment durations and maintenance are acne and atopic dermatitis (AD). In these situations, studies have found satisfactory outcomes without side effects using probiotics. In vitro trials indicate the potential to directly suppress acnes development by producing antibacterial proteins (bacteria) and immunomodulatory effects of probiotics, such as *Streptococcus salivarius* and *Enterococcus faecalis*. It has been demonstrated that probiotics have direct (inhibited *P. acnes*) and indirect (reduce the inflammatory response) advantages [62, 63].

#### **2.6 Influence of probiotics on mental health and disease**

Dinan and Cryan [64] think that the intricate bidirectional connection that happens between the brain and gut microbiota (GM) might be a novel approach to determine mental disease treatments. Several studies have found that the GM plays a substantial influence in an individual's mood and behavior, and that it might be very useful in mental health therapy. Stress-induced physiological consequences in the stomach, such as nausea and spells of diarrhea, have a significant impact on the GM balance [65].

Psychobiotics are a novel type of probiotic that is intended to help people with psychiatric illnesses by enhancing their cognitive abilities [66] Many different gut microbial species generate a variety of mood-regulating neuromolecules, which has an impact on host physiology. GABA is produced by *Bifidobacterium* and *Lactobacillus* species, whereas serotonin is produced by *Enterococcus, Escherichia, Streptococcus, and Candida species*, and dopamine is produced by *Bacillus* species [67].

#### **2.7 LAB with in vitro, in situ cholesterol-lowering characteristics**

Cholesterol reduction is one of the most favorable properties for probiotic bacteria with lactic acid. In this work, a capability evaluation was carried out of 58 possibly probiotic bacteria containing cholesterol and bile acids for in vitro digestion and cholesterol reductions. The best-performing strains reduced cholesterol levels in broth by 42–55% and were tested in the production of cheese.

In all cheeses, the cholesterol content declined during maturation. The most significant decreases (up to 23%) were obtained by adding *LB. paracasei, paracasei* VC2161 and *Epilithonimonas lactis* BT 161 during cheese-making, all strains were present in the cheese at levels greater than 107 cfu/g up to 60 days after ripening. There was no detrimental influence on the sensory properties of cheese in the adjacent cultures. These strains with demonstrated in vitro characteristics are, therefore, ideal candidates for new probiotic formulations, and can also be utilized to make foods like dairy fermented products effective.

#### **2.8 Probiotic strains**

Probiotic microbe selection is based on safety, function, and technology, as described in the following reports. Some probiotic microorganisms are already on the market and have been thoroughly investigated. They must first be able to be produced under industrial circumstances before probiotic strains may be provided to

## *Probiotics in Processed Dairy Products and Their Role in Gut Microbiota Health DOI: http://dx.doi.org/10.5772/intechopen.104482*

customers. Then, throughout the storage of the crops frozen or freeze-dried as well as food items into which they are formulated, they must survive and keep their functioning. Furthermore, they need to be incorporated into plates without producing flavors or texture. For functional dietary requirements, the following aspects in relation with the probiotic should be considered: Preparing for large-scale manufacturing should be feasible, remain stable and viable for storage and use.

## *2.8.1* Lactobacillus rhamnosus *GG*

Studies have demonstrated the promotion of immunoregulatory activities by raising regulatory cytokines of interleukin (IL)-10 [68] and the induction of beta (TGF-β) transforming T-cells [69]. In fact, atopic children have proven that the gut microbiota differs from atopic ones. LGG showed a beneficial impact on atopic illness prevention while randomized clinical studies (RCTs) reveal no outcomes [70, 71].

LGG in babies with rotavirus-related diarrhea led to higher increased production of non-specific antibodies and anti-rotavirus antibodies. The neonatal evidence of necrotizing enterocolitis, improving food tolerance and prevention of pathogens colonizing intestine because of competition exclusion, preventing adhesion, and improving mucosal immunoglobulin A (IgA), has shown LGG to be effective in reducing incidences of necrotizing enterocolitis. A new retrospective 6-year cohort study on LGG in extremely small birth weight babies showed the microbiological safety of the strain [72].
