Aims:To evaluate the effectivity of Lactobacillus plantarumBSL isolated from Indonesian sauerkraut against Listeriamonocytogenes ATCC 7644through in vitroand in vivoassay. Methodology and results:In vitroexamination for antimicrobialactivity against L.monocytogenesATCC 7644was performed using seven isolates of lactic acid bacteria (LAB). LactobacillusplantarumBSL demonstrated the highest activity against L. monocytogenesandstudied further in Sprague-Dawley (SD) rats. Treatmentgroup of rats received 0.5 mL culture suspension (109CFU/mL) of L. plantarumBSL and control group received 0.5 mL of 0.85% w/v NaCl daily during nine days of treatment. Both groups were infected at 3rd day with0.5 mL of suspension of L. monocytogenes (109CFU/mL). At the 2nd(before infection), 5th, 7th, and 9thday (after infection), the rats were sacrificed and the faeces, caecum, and caecum content were examined for the population of LAB and L. monocytogenes. Administration of L. plantarumBSL significantly increased the population of LABby 1.2–1.4 log unit, while the number of L. monocytogeneswas reduced by 1.8–1.9 log unitcompared to control group eithr in the faeces, caecum, or caecum content. Administration of L. plantarumBSLcould be able to reduce the liver and spleen damageof the experimental rats, butdid not show any changes in immunoglobulin A (IgA) response in comparison with control group. Conclusion, significance and impactofstudy: LactobacillusplantarumBSL was promising as probiotic candidate with health promotion to protect the gastrointestinal from infection by L. monocytogenesATCC 7644.

Aims: This study was conducted to observe the stability of Spondias pinnata leaf (SPL) extract antibacterial at different pH, salt concentration and temperature, to examine its antibacterial effectivity on minced fish, and to determine its fraction’s antibacterial mechanism. Methodology and results: The tested SPL ethanolic extract, n-hexane, chloroform, ethyl acetate and water fractions’ antibacterial activity against Bacillus cereus and Vibrio parahaemolitycus. Its stability against pH, salt, and thermal variation was studied, as well as the mechanism and application in fish. Ethyl acetate fraction and water fraction showed the highest activity against B. cereus (MIC 0.62 mg/mL). Protein profile analysis using gel electrophoresis showed that B. cereus cells exposed with SPL ethyl acetate fraction and water fraction showed thinner protein bands as compared to control. Severe damage of the cells treated with 3 MIC was also observed under SEM. Antibacterial activity of SPL ethanolic against Bacillus cereus and Vibrio parahaemolitycus were stable against heat treatment (80–121 °C for 15 min) and NaCl treatment (0–10% w/v), whereas the inhibition zone respectively at pH 4 (10.31±0.25 and 8.09±0.97 mm) was higher than pH 7 (8.45±0.52 and 6.66±1.84 mm). Application of SPL ethanolic extract in fish broth showed higher antibacterial activity than in fish flesh, which gave bactericidal effect at 3 MIC. Conclusion, significance and impact of study Ethanol extract can be developed as a natural preservative in fish

Aims: To characterize the plantaricin IIA-1A5 crude extract that biosynthesized by Lactobacillus plantarum IIA-1A5 using corn steep liquor (CSL) based medium. Methodology and results: Lactobacillus plantarum IIA-1A5 was grown in several media containing different components including corn steep liquor (CSL), molasses and MRS (de Man Rogosa Sharpe) as control medium for 24 h at 37 °C. Antibacterial activities of the cell-free supernatant were expressed as diameter of inhibition zones observed by paper disc method. The results showed that CSL medium produced cell-free supernatant of L. plantarum IIA-1A5 with significantly higher antibacterial activity againts Staphylococcus aureus ATCC 25923 (9.81 mm), Lactobacillus monocytogenes ATCC 7644 (9.61 mm), Bacillus cereus (8.97 mm) and Escherichia coli ATCC 25922 (9.23 mm) were not significantly different compared to control MRS broth media (9.59 mm). CSL medium added only with 3% yeast extract and Tween 80 produced supernatant which showed similar antibacterial activity either to 10% molasses or control medium (Medium K and B). The CSL medium was considered more efficient and low cost, therefore this medium was selected for production and characterization of plantaricin IIA-1A5 crude extract. Further characterization performed by SDS PAGE analysis showed that crude plantaricin had molecular weight of approximately 9.9 kDa, higher than that produced in control medium (8.0 kDa). However, both plantaricins were categorized under the same class for small bacteriocin (class II). This study also revealed the plantaricin IIA-1A5 produced in CSL medium was stable to heat and pH and not significantly different compared to control MRS broth media. The antibacterial activity of plantaricin IIA-1A5 crude extract against S. aureus ATCC 25923 (10.09 mm) was not significantly different with 1000 ppm sodium benzoate (9.70 mm) and 300 ppm sodium nitrite (9.82 mm). Conclusion, significance and impact of study The CSL medium produced cell-free supernatant of L. plantarum IIA 1A5 had significant antibacterial activity characterization againts S. aureus ATCC 25923, L. monocytogenes ATCC 7644, B. cereus and E. coli ATCC 25922. Comparison of the inhibition activity of plantaricin IIA-1A5 crude extract against pathogen with synthetic preservatives indicated that plantaricin IIA-1A5 crude extract have the potency to replace synthetic preservatives. CSL based medium is potential to be used for low-cost plantaricin IIA-1A5 production.
Anti-Bacterial Agents--metabolism ; Bacteriocins--metabolism ; Lactobacillus plantarum ; Microbial Viability--drug effects ; Staphylococcus aureus