In vitro Organic Acid Production and In Vivo Food Pathogen Suppression by Probiotic S. thermophilus and L. bulgaricus

Abstract

Foodborne pathogens are a major source of morbidity and mortality worldwide. For this cause, exploring various effective ways of suppressing their spread is at the forefront of many research projects. The current study aims to investigate the in vitro organic acid production of S. thermophilus KLDS 3.1003 and L. bulgaricus KLDS 1.0207 strains, their in vivo suppression of and immuno-modulatory effects against E. coli ATCC 25922 and S. aureus ATCC 25923 pathogens. First, lactic and acetic acid production using three carbon sources – 1% glucose (control), 1% sucrose, and 1% fructo-oligosaccharides (FOS) – was determined by HPLC. For the in vivo section, a total of 40 BALB/c mice were purchased and divided into 10 treatment groups (control and nine treatments). Animals were given 1 week to acclimatize and then fed treatment diets for 14 days. Afterward, hematological (RBC, WBC, HB, PLT, Neutrophils, Eosinophils, Lymphocytes, and Monocytes) and histopathological analyses were carried out. All analyses were done in triplicate. Results show that lactic and acetic acid productions for both strains increased with supplementation and were highest after 1% FOS addition. Regardless of carbon source, L. bulgaricus KLDS 1.0207 produced higher ( P < 0.05) amounts of lactic and acetic acids than S. thermophilus KLDS 3.1003. Also, generally better hematological parameters in probiotic groups than the control ( P < 0.05) were observed. In some instances, mice in probiotic treatment groups had better immunity levels (lymphocytes, monocytes, neutrophils, eosinophils) than those in the control and pathogen groups. Histopathological studies showed that no anomalies were associated with S. thermophilus KLDS 3.1003 and L. bulgaricus KLDS 1.0207 administration. In conclusion, S. thermophilus KLDS 3.1003 and L. bulgaricus KLDS 1.0207 strains are not only probiotic candidates but can have therapeutic applications.

Lactobacillus delbrueckii subsp. bulgaricus KLDS 1.0207 Exerts Antimicrobial and Cytotoxic Effects in vitro and Improves Blood Biochemical Parameters in vivo Against Notable Foodborne Pathogens

“…Earlier, Bian et al (2015) showed that antimicrobial substances produced by L. helveticus KLDS 1.8701 could inhibit a range of foodborne pathogens, especially L. monocytogenes ATCC119115. Also, L. bulgaricus KLDS 1.0207 can produce sufficient pathogen-inhibiting organic acid (lactic and acetic acids) in vitro, and this increased with carbon source supplementation (Evivie et al, 2019). Our recent report and findings from the current study strongly suggest that the inhibitory properties exhibited by this strain can be attributed to acid metabolites.…”

“…bulgaricus KLDS 1.0207, isolated from traditional dairy products from Sinkiang Province, China, has shown promising attributes recently in alleviating lead (Pb) toxicity in vivo in both prevention and treatment groups (Li et al, 2017). Besides, it can produce high amounts of pathogen-suppressing organic acid in vitro, improve immunity functions, and prevent organ damage in vivo (Evivie et al, 2019). However, nothing is known about its antimicrobial anti-inflammatory and tolerance properties (in vitro).…”

Evaluation of the probiotic and postbiotic potential of lactic acid bacteria from artisanal dairy products against pathogens

“…High lactate production is a hallmark of this species. Of the two species most frequently used as starters in commercial yogurt making, L. delbrueckii produces greater amounts of lactate than S. thermophilus [47]. Production of both lactic and acetic acids as seen here, can act synergistically to produce low pH [48].…”

A food-grade vector for Streptococcus thermophilus based on the α-complementation of β-galactosidase

“…These methods may help provide ideas for improving heterologous protein expression in S. thermophilus. Nevertheless, S. thermophilus as a traditional starter for yogurt is a potential probiotic (Evivie et al, 2019). It not only has remarkable fermentation characteristics but also plays a positive role in maintaining intestinal health (Vitetta et al, 2019).…”