Artisanal Coalho cheeses as source of beneficial Lactobacillus plantarum and Lactobacillus rhamnosus strains

Abstract

Based on screening for potential beneficial lactic acid bacteria from Coalho cheese produced in the North-East region of Brazil, eight strains belonging to Lactobacillus rhamnosus and Lactobacillus plantarum were selected. All investigated strains presented low levels of hydrophobicity. Different levels of coaggregation were Dairy Sci. & Technol. (2015) 95:209-230 DOI 10.1007 observed for tested Lb. rhamnosus and Lb. plantarum with Listeria monocytogenes. All strains were able to grow in presence of 0.5% of the sodium salts of taurocholic acid (TC), taurodeoxycholic acid (TDC), and glycocholic acid (GC) and showed the ability to deconjugate only TC, TDC, and GC. Investigated Lb. rhamnosus and Lb. plantarum strains showed good survival when exposed to the conditions simulating the GIT conditions. Lb. rhamnosus and Lb. plantarum strains were tested for presence of virulence, antibiotic resistance, and biogenic amine production genes. In addition, minimum inhibititory concentration (MIC) of selected antibiotics was determined. Production of antimicrobial peptides (bacteriocins) was investigated. However, only Lb. rhamnosus EM253 produced bacteriocin at level 800 arbitrary unit (AU) mL −1 against L. monocytogenes 211. The bacteriocin remained stable at pH from 2.0 to 10.0 and after exposure at 100°C for 120 min and in presence of surfactants and salts. Studied Lb. rhamnosus and Lb. plantarum strains showed good potential to be applied as a functional coculture/s with beneficial properties in the production of Coalho cheese.

Survival of Lactobacillus rhamnosus EM1107 in simulated gastrointestinal conditions and its inhibitory effect against pathogenic bacteria in semi-hard goat cheese

“…lactis and L. lactis subsp. cremoris, considering the starter potential previously identified for L. rhamnosus EM1107 (Santos et al, 2014). After the removal of around 90% of whey, the cheese curd was salted with 0.8 g/L NaCl, based on the initial milk volume.…”

“…In a previous study, the new Lactobacillus rhamnosus EM1107 strain, isolated from bovine Coalho cheese was evaluated for technological, safety and functionality aspects and proven to be a promising probiotic candidate for use in fermented dairy products (Santos et al, 2014). However, other analyses are mandatory to assess the viability of the strain as a probiotic micro-organism for these types of food matrices.…”

Characterization of Probiotic Abilities of Lactobacilli Isolated from Iranian Koozeh Traditional Cheese

“…The LAB strains were inoculated onto surface of MRS agar medium. The disks were then used on MRS agar plates and incubated at 37°C for 24 h. Levels of the applied antibiotics including amoxicillin, ceftriaxon, chloramphenicol, erythromycin, gentamycin, streptomycin, tetracycline and vancomycin were 25, 30, 30, 15, 10, 10, 30 and 30 μg per disk, respectively [dos Santos et al, 2015]. Inhibition zone diameters in millimeter (mm) were measured to assess the strain sensitivity.…”

“…Overall, a probiotic lactobacillus should be able to survive (at least 10 6 CFU/mL) during the food processing steps and the product shelf-life, and should be also desirable to offer a contribution to the sensory attributes of the fi nal product [dos Santos et al, 2015]. The new probiotic strains must also be resistant to the adverse conditions of the human gastrointestinal tract that have physiological properties compatible with probiotic potential and technological relevance for use in food products [Kirmaci, 2016;El-Shafei et al, 2008;Makinen et al, 2012].…”

Activity of metabolites produced by new strains of Lactobacillus in modified de Man, Rogosa and Sharpe (MRS) medium against multidrug-resistant bacteria

“…Lactobacilli isolates (n=9) were identified by Polymerase Chain Reaction (PCR), according to Dos Santos et al, 2015, DNA was extracted using ZR Fungal/bacterial DNA kit (ZymoReasearch, Irving, CA, USA). Taxonomical identification was confirmed by sequencing of the PCR-amplified 16S rRNA using the universal pair of primer 8F (5′-CAC GGA TCC AGA CTT TGA TYM TGG CTC AG-3′) and the reverse primer 1512R (5′-GTG AAG CTTACG GYTAGC TTG TTA CGA CTT-3′), where Y means C + T and M means A + C. In order, to differentiate Lactobacillus casei, Lactobacillus paracasei and Lactobacillus rhamnosus, an average 400 base pair fragments from 16 to 23S intergenic spacing region were also PCR-amplified and sequenced, using the pair of primers Lu-5 (5′-CTA GCGGGT GCG ACT TTG TT-3′) and Lac-2 (5′-CCT CTT CGC TCG CCG CTA CT-3′).…”