Partial characterization of probiotic lactic acid bacteria isolated from Chinese dairy products

Abstract

A total of 246 bacterial isolates were collected from various food and animal sources within Nanning city, China. Sequencing of the 16S rRNA gene revealed that 24.4% of the isolates were lactic acid bacteria (LAB). Initial screens identified three isolates from semi-hard cheese: Lactobacillus plantarum subsp. plantarum strains K3 and K4 and Lb. paracasei subsp. tolerans K8; and one from raw buffalo milk: Lb. plantarum subsp. plantarum E41 as having the highest levels of cell surface hydrophobicity and autoaggregation. Further characterization of these strains showed that all four isolates were completely stable after exposure to the pepsin and trypsin for 6 hours, and strains K8 and E41 remained viable after 6 hours of exposure to acidic conditions (pH 2.5) and bile salts (0.3%). In addition, strains K3 and K4 were shown to inhibit the growth of potential human pathogens, including methicillin resistant Staphylococcus aureus, Escherichia coli and Salmonella typhi, with inhibition zones being >14 mm for each bacterial target. Results from this study suggested that the four characterized LAB strains could survive passage through the gastrointestinal tract, thus supporting the need for additional studies to assess their potential as probiotics.

Genomic and Phenotypic Characterization of Mastitis-Causing Staphylococci and Probiotic Lactic Acid Bacteria Isolated from Raw Sheep’s Milk

“…Aliquots of 150 μL of each bacterial suspension were transferred to a 96-well microplate (Thermo Fisher Scientific, Lillerød, Denmark, 167008) and left for 0.5 h at room temperature ( A ). The cell surface hydrophobicity was calculated using the following equation [ 86 ]: where A 0 and A are the initial (0 h) and final (after 0.5 h) OD 600 , respectively.…”

Towards the diversification of lactococcal starter and non‐starter species in mesophilic dairy culture systems

“…A recent survey of Chinese dairy products identified L. petauri in raw buffalo milk, fermented buffalo milk and the area around the buffalo udder (Huang et al, 2021 ). Similarly, L. petauri strains were isolated from traditional Montenegrin brine cheeses and the genome of L. petauri INF110 was found to harbour the antibiotic resistance‐associated genes, mdtA and clpI (Martinovic et al, 2021 ).…”

Buffalo Yogurt Fortified with Eucalyptus (Eucalyptus camaldulensis) and Myrrh (Commiphora Myrrha) Essential Oils: New Insights into the Functional Properties and Extended Shelf Life

“…Radical scavenging activity was carried out according to [30,31]. In brief, watersoluble extract (WSE) was prepared in 0.1 M sodium phosphate buffer, pH 7.0, containing 1% (wt/vol) Triton X-100, and 2,2-diphenyl-1-picrylhydrazyl (DPPH; 100 µM) was prepared in organic solvent (methanol).…”