• Journal of Food Hygiene and Safety
• /
• v.36 no.6
• /
• pp.488-492
• /
• 2021

One of the well characterized bacteriocins, nisin, shows strong antimicrobial activity against pathogenic bacteria such as Listeria monocytogenes and Staphylococcus aureus. This study evaluated the synergistic effect of commercial nisin and SAP84 bacteriophage on S. aureus. Nisin showed antimicrobial activity against S. aureus KCTC 3881 in a dose-dependent manner. Eighteen IU/mL of the nisin decreased 4.03 Log CFU/mL of the strain in MRS broth after six hours compared with the controlled subject. On the other hand, the same dose of the nisin decreased 5.54 Log CFU/mL when co-treated with 0.1 MOI of the bacteriophage SAP84. Furthermore, the combination of nisin and SAP84 was successfully applied for controlling the S. aureus strain in lettuce.

• Journal of Food Hygiene and Safety
• /
• v.20 no.4
• /
• pp.211-216
• /
• 2005

The bacteriocin produced by E. faecium MJ-14 was precipitated with $50\%$ saturated ammonium sulfate in MRS broth and then the precipitated protein was dissolved in 20 mM sodium phosphate buffer (pH 6.0). The crude bacteriocin was purified by CM-sepharose CL 6B and Sephacry S-100 column chormatograhy. In this case, the purification fold of the bacteriocin was 114, therefore, its activity was 127,293 BU/mg of specific activity. Result from SDS-PAGE of the purified bacteriocin, it was obtained two protein bands of 4.3 kDa and 5.8 kDa having antilisterial activity.

• Journal of Life Science
• /
• v.20 no.6
• /
• pp.934-939
• /
• 2010

We have previously reported recombinant productions of bacteriocins using yeast expression plasmid pAUR123, which contains the alcohol dehydrogenase (ADH) promoter, in Saccharomyces cerevisiae cells and their antibacterial activities. In order to improve the antibacterial activities of bacteriocidal yeast cells, a strong glyceraldehyde phosphate dehydrogenase (GPD) promoter gene of S. cerevisiae was amplified and inserted upstream into bacteriocin genes such as the OR-7, Subpeptin JM4-A or JM4-B gene in the corresponding recombinant yeast plasmid. Yeast cells transformed by the recombinant plasmid containing the GPD promoter represented higher antibacterial activities against both Gram positive B. subtilis and Gram negative E. coli cells compared to those transformed by the corresponding recombinant plasmid containing the ADH promoter. Thus, yeast cells harboring the recombinant plasmid containing the GPD promoter constructed in this study could be applied in the food preservative or animal feed industries.

• Journal of Dairy Science and Biotechnology
• /
• v.17 no.1
• /
• pp.1-10
• /
• 1999

A bacteriocin produced by Lab. acidophilus GP4A isolated from fecal contents of pig was characterized. Lab. acidophilus GP4A produced a heat-stable and pH-resistant bacteriocin, which was hydrolyzed by trypsin and pepsin and active against various microorganisms. Lab. acidophilus GP4A produced bacteriocin at maximum rate when grown in MRS broth(pH 6.5${\sim}$7.5) at$37^{\cric}C$ or $40^{\cric}C$. The bacteriocin produced by Lab. acidophilus GP4A inhibited the growth of Lactobacillus delbrueckii subsp. lactis 4794 in early logarithmic phase. The bacteriocin was purified by ammonium sulfate precipitation and Octyl sepharose CL-4B column chromatography. The purification resulted in a final yield of 21.7% and a 13.6-fold increase in the specific activity.

• Food Science of Animal Resources
• /
• v.22 no.1
• /
• pp.81-86
• /
• 2002

A bacteriocin producing lactic acid bacteria was isolated from ground beef and the strain was identified as Lactobacillus plantarum ssp. by use of API carbohydrate fermentation pattern and physiological tests. The bacteriocin produced by L. plantarum KU107 exhibited a good spectrum of activity against foodborne pathogens including Bacillus cereus, Escherichia coli, Listeria ivanovii, Listeria monocytogenes, Pseudomonas aeruginosa, Pseudomonas chlororaphis, Staphylococcus aureus, Staphylococcus intermedius, Salmonella typhimurium and Yersinia enterocolitica. The bacteriocin was active over a wide pH range and stable of heat treatment, and inactivated by treatment with proteases. A bacteriocin from L. plantarum KU107 was effetive in reducing S. aureus in tryptic soy broth. On the ground beef containing S. aureus was added with the crude bacteriocin, S. aureus was inhibited during storage period at 4$\^{C}$.

• Korean Journal of Microbiology
• /
• v.47 no.1
• /
• pp.74-80
• /
• 2011

Bacteriocin-producing lactic acid bacterium having antagonistic activity against Bacillus cereus, was isolated from Kimchi. The selected strain was identified as Lactococcus lactis by the Bergey's manual and 16S rDNA analysis, and named as L. lactis ET45. The bacteriocin was stable in the pH range 3.0-11.0. The bacteriocin was active over a wide temperature range from $40^{\circ}C$ to $121^{\circ}C$. Optimal culture condition for producing bacteriocin was obtained by growing the cells on MRS medium at pH 7.5 and $30^{\circ}C$ for 18 h. Antibacterial activity of the bacteriocin was completely disappeared by proteinase K, and this means that bacteriocin is a proteinous substance. The molecular weight of bacteriocin was estimated to be about 4.5 kDa by tricine sodium dodecyl sulfate polyacryamide gel electrophoresis (TSDS-PAGE).

• Journal of Dairy Science and Biotechnology
• /
• v.38 no.3
• /
• pp.154-160
• /
• 2020

Physical and sensory characteristics of commercial yogurts are important aspects for consumer acceptability. In addition, beneficial functions of commercial yogurts are also emphasized for the probiotic dairy products. The aim of this study was to investigate the functional properties of yogurts with the combination of bacteriocin-producing Pediococcus acidilactici. Yogurts fermented with commercial starter culture (control yogurt) and control yogurt together with P. acidilactici HW01 (yogurt+HW01), P. acidilactici JM01 (yogurt+JM01), or P. acidilactici K10 (yogurt+K10) were prepared. During 28 days after fermentation, the viability of lactic acid bacteria, pH, and brix, in the yogurt samples were assessed with standard methods. Moreover, to investigate the antilisterial activity of the yogurt samples, Listeria monocytogenes was simultaneously inoculated when the yogurts were prepared with lactic acid bacteria, and the viability of L. monocytogenes was determined. Although yogurt+K10 did not completely remove L. monocytogenes, control yogurt, yogurt+HW01, and yogurt+JM01 eradicated L. monocytogenes at day 2 after fermentation. However, yogurt+K10 also removed L. monocytogenes at day 3 after fermentation. Taken together, these findings suggest that the combination of yogurt with P. acidilactici does not affect its quality and they may consequently aid in the development of new probiotic yogurt.

• Journal of Dairy Science and Biotechnology
• /
• v.31 no.2
• /
• pp.153-159
• /
• 2013

Lactic acid bacteria are microorganisms that are closely associated with human and/or animal environments, and are categorized as generally recognized as safe (GRAS) organisms due to their ubiquitous appearance in foods and their contribution to the healthy microflora of mucosal surfaces. This study was performed to isolate and identify lactic acid bacteria with antagonistic effects against food-borne pathogens. A total of 3,000 acid-producing bacteria were isolated from infant feces, cattle feces, goat feces, dog feces, pig feces, vaginal tracts, vegetables, fruits, Kimchi, Jeotgal, fermented sausages, raw milk, cheese, yogurt, Cheonggukjang, Meju, and Makgeolli cultured on MRS agar with 0.05% bromocresol purple. For the isolation of bacteriocin-producing bacteria, the diameter of the clear zone was measured on MRS agar plates. Twenty-six isolates exhibited strong antibacterial activity against indicator strains such as Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella enterica serovar Enteritidis. Lactic acid bacteria were identified as Enterococcus faecalis, Enterococcus faecium, Enterococcus hirae, Lactobacillus acidophilus, Lactobacillus amylovorus, Lactobacillus curvatus, Lactobacillus plantarum, and Pediococcus acidilactici by 16S rDNA gene sequence analysis. The results of this study suggest that the isolates could be used as potential probiotic starters for functional food applications.

• Korean Journal of Food Science and Technology
• /
• v.32 no.6
• /
• pp.1358-1364
• /
• 2000

A mixed culture of bacteriocin-producing lactic acid bacteria and yeast was used to prepare unique fermented fruit and vegetable beverage which contains bacteriocin. Fruit and vegetable broth fermented by Lactococcus lactis 11454 showed inhibitory activity against foodborne pathogens such as Listeria monocytogens and Staphylococcus aureus, and Streptococcus mutans which is a major causative agent for dental caries. Bacteriocin was detected at the end of fermentation of fruit and vegetables and its antimicrobial activity was stable for 5 weeks during storage at $4^{\circ}C$. These results suggest that the presence of bacteriocin in beverages during fermentation and storage will provide a safeguard against foodborne pathogens and spoilage bacteria. To improve flavor of the fermented broth, post-fermentation of the fermented broth was carried out at $4^{\circ}C$ by using yeast isolated from raw material mixture. Total acidity of the post-fermented broth was slightly decreased, but significant increase in the concentration of succinic acid was observed in the post-fermented broth. It was also observed that bitter and disagreeable taste compounds such as phthalates were decreased, and mild acidic and fruity flavor esters and alcohols were increased by the post-fermentation of the fermented broth with yeast.

• Journal of Dairy Science and Biotechnology
• /
• v.38 no.1
• /
• pp.53-57
• /
• 2020

Culture concentrate of probiotic Lactobacillus johnsonii PF01 inhibited the growth of Staphylococcus aureus, which was confirmed by agar well diffusion method. Protease treatment of PF01 culture concentrate indicated that the antimicrobial substance of PF01 was a bacteriocin. Investigation of PF01 genome revealed the existence of a gene similar to that of helveticin, which showed 34.9% and 41.0% identity with those of L. helveticus 481 and L. crispatus K313, respectively, thereby suggesting that the bacteriocin produced by strain PF01 is a helveticin homolog.