Location: Dairy and Functional Foods ResearchTitle: Partial Characterization of Probiotic Lactic Acid Bacteria Isolated from Chinese agricultural products
|HUANG, LI - Chinese Academy Of Sciences|
|GODA, HANAN - Cairo University|
|ABDEL-HAMID, MAHMOUD - Cairo University|
|YANG, PAN - Chinese Academy Of Sciences|
|HUANG, ZIZHEN - Chinese Academy Of Sciences|
|ZENG, QING-KUN - Chinese Academy Of Sciences|
|LI, LING - Chinese Academy Of Sciences|
Submitted to: International Journal of Food Properties
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/3/2021
Publication Date: N/A
Interpretive Summary: Lactic acid bacteria (LAB) have been used for centuries to produce a variety of fermented foods, including yogurt and cheese. Additionally, several species of LAB have received interest for their potential to serve as probiotics, conveying health benefits to humans or animals following consumption. This study focused on isolation and characterization of LAB from several agricultural sources in Nanning, China. A total of 246 bacterial isolates were recovered, of which 60 were identified as LAB using molecular techniques. Of the LAB isolated, only four of the LAB Lactobacillus plantarum strains K3 and K4, and Lactobacillus paracasei strain K8 from buffalo milk cheese; and Lactobacillus plantarum strain E41, from raw buffalo milk displayed the potential probiotic traits that suggested they can adhere to cells within the gastrointestinal tract. These strains were also shown to survive exposure to acidic conditions, digestive enzymes, and bile salts; although bile salts significantly reduced the number of viable cells for strains K3 and K4. Additionally, strains K3 and K4 were shown to inhibit the growth of harmful bacteria, including Escherichia coli, Salmonella typhi and Staphylococcus aureus. These results suggest that the four LAB isolates can survive passage through the gastrointestinal tract and should be further evaluated for specific probiotic activities, in addition to the antimicrobial activities described.
Technical 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 auto-aggregation. 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 six hours of exposure to acidic conditions (pH 2.5) and bile salts (0.3%). Additionally, strains K3 and K4 were shown to inhibit the growth of potential human pathogens, including methicillin resistant Staphylococcus aureus, Escherichia coli and Salmonella typhi. Results from this study suggest 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.