Characterization and antimicrobial activities of lactic acid bacteria isolated from selected Nigerian traditional fermented foods

Abstract

For production and preservation of traditional fermented foods, the genera, lactic acid bacteria (LAB) have been used. This study was carried out to determine the characteristics and the antimicrobial activities of lactic acid bacteria isolated from selected Nigerian traditional fermented foods. Changes in pH and titratable acidity (TA) of the samples were investigated for a period of four days (96 h). Eleven tentative LAB from fermented maize and cassava (Ogi and Fufu, respectively) were isolated and characterized. The spoilage organisms from fish were aseptically identified and the antimicrobial activity was determined by agar well diffusion method against three isolated food spoilage organisms (Pseudomonas aeruginosa, Enterobacter aerogene and Bacillus cereus). The isolates were selected and further identified as Lactobacillus amylolyticus strain L6, Lactobacillus plantarum strain ci-4w and Lactobacillus sakei strain MLS1 by the aide of genotypic characteristics (16S rRNA gene sequences). These strains were screened for their EPS producing activity, resistance to low pH and bile salts as well as bacteriocin activity. These strains can be used as starter culture or protective cultures to improve the hygiene, quality and increased safety of the food products by inhibiting the food borne pathogens and spoilage microorganisms.

Investigating lactic acid bacteria genus Lactococcus lactis properties: Antioxidant activity, antibiotic resistance, and antibacterial activity against multidrug-resistant bacteria Staphylococcus aureus

“…That signified this activity relates to the competition for nutrients with harmful bacteria. Nutrients, space, and antimicrobial active metabolites are considered among the antimicrobial properties of LAB [ 14 , 32 ].…”

“…Scientists are encouraged to search for LAB from natural sources in response to the rising interest in products with nutritional and practical properties [ 31 ]. LAB has received a great deal of attention because of the health-enhancing properties of some LAB, called probiotics [ 32 ]. Probiotic LAB is generally considered safe and beneficial to health [ 33 , 34 ].…”

Probiotic properties and antibiotic susceptibility assessment of Streptococcus thermophilus isolates

“…The antibacterial activity of LAB has many reasons, which include: nutrient competition, bacteriocins, hydrogen peroxide production and pH lowering by the production of organic acids [11,26]. Today, researchers are interested in the search for safe, natural and accessible antimicrobials [27].…”

“…thermophilus) is gram-positive, anaerobic, aero-tolerant, catalase-negative, homo-fermentative, able to grow at high temperatures 45°C. It is one of probiotic bacterial strain that found in milk, cheese, and yogurt [11]. Although, Streptococcus thermophilus is one of food species, but it has contradictory interspeci c interactions (commensal and opportunistic species) [12].…”