• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.65-69
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• 2003

The effects of grapefruit seed extract and $H_2O_2$ disinfectants on Pseudomonas aeruginosa were investigated by antimicrobial assay and scanning electron microscopy. Pseudomonas aeruginosa is a Gram negative bacteria and a common causative microorganism of bacterial keratitis. After incubation of soft contact lens in Pseudomonas aeruginosa suspension for 120 minutes containing the disinfectants, the grapefruit seed extract showed antimicrobial activity as good as the chemical disinfectant. The living rates of Pseudomonas aeruginosa in grapefruit seed extract and $H_2O_2$ disinfectants were $1{\times10^3CFU/m{\ell}$ and $0.5{\times}10^3CFU/m{\ell}$, respectively showing no major difference in the killing activity. However, the mechanisms of the antimicrobial activity were quite different as indicated by scanning electron microscopy of the bacterial surface morphology. Considering chemically or other toxins induced keratitis, the natural disinfectant isolated from grapefruit seed extract shows promising results as a soft contact lens disinfectant.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.10
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• pp.1466-1470
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• 2009

This study was focused on the development of anticariogenic edible films using pullulan containing grapefruit seed extract (GFSE), polylysine or propolis. According to the result of antimicrobial activity (disc diffusion method) of GFSE, polylysine and propolis against Streptococcus mutans, antimicrobial pullulan film was produced by adding grapefruit seed extract. The optimum combination of pullulan and sorbitol (plasticizer) was 10$\sim$15% (w/v) and 40$\sim$50% of pullulan (w/w), respectively. Minimum concentration of grapefruit seed extract for growth inhibition of Str. mutans was 50 ppm in medium. Formulation of antimicrobial pullulan films containing grape seed extract was established and these results evidently showed potential for commercial application.

• Applied Biological Chemistry
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• v.33 no.2
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• pp.169-173
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• 1990

The anthraquionone mycotoxin, skyrin, is produced by Penicillium islandicum. DF-100 which was extracted from grapfruit seed extract and is a natural organic complex inhibited the biosynthesis of skyrin by Penicillium islandicum. This study was carried out to determine the potential of DF-100 to support Penicillium islandicum and skyrin production. DF-100 inhibited the growth of the fungus at 750ppm or less and caused complete inhibition of skyrin production at 500ppm or less. DF-100 appears to block the incorporation of emodinathrone into skyrin and an enzymatic step in the skyrin biosynthetic pathway which lies before skyrinanthrone.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.4
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• pp.705-710
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• 2004

This study was conducted to investigate the difference of antimicrobial activity between $\varepsilon$-polylysine/grapefruit seed extract mixture and $\varepsilon$-polylysine/glyceride mixture against food-borne pathogens. The minimum inhibitory concentration (MIC) of the $\varepsilon$-polylysine/grapefruit seed extract mixture was 100 times lower than that of the $\varepsilon$-polylysine/glyceride mixture. In case of the $\varepsilon$-polylysine/glyceride mixture the MIC of Bacillus cereus (0.1 $\mu$L/mL) and Pseudomonas aeruginosa (0.1 $\mu$L/mL) were lower than that of Escherishia coli (15 $\mu$L/mL). When rices were cooked with the $\varepsilon$-polylysine/glyceride mixture the number of total microbial cell was decreased during storage at 2$0^{\circ}C$ as concentration of the $\varepsilon$-polylysine/glyceride mixture increased. The antimicrobial activity was the highest against Escherishia coli as the concentration of the $\varepsilon$-polylysine/glyceride mixture increased. Sensory terms such as taste, flavor and texture were not significantly different in cooked rices prepared with 0.5% $\varepsilon$-polylysine/glyceride mixture, but there was significantly different in cooked rices prepared with 1% (p＜0.05) in the overall acceptability, indicating that the cooked rice with 0.5% $\varepsilon$-polylysine/glyceride mixture was recommended.

• Applied Biological Chemistry
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• v.49 no.2
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• pp.108-113
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• 2006

This study was conducted to analyze the acidity and turbidity changes of immersion solutions as well as changes in aerobic bacteria, E. coli, anaerobic bacteria, yeast and mold counts of mulberry leaf soybean curds during storages at $4^{\circ}C$ and $25^{\circ}C$ in different immersion solutions such as distilled water, grapefruit seed extract (300 ppm) and alkaline ionic water. The acidities of immersion solutions of distilled water, grapefruit seed extract and alkaline ionic water after 18 days of storage at $4^{\circ}C$ were 0.021, 0.008 and 0.002%, respectively. After 5 days of storage at $25^{\circ}C$ were 0.042, 0.029 and 0.009%, respectively. The turbidities of the above mentioned immersion solutions were 0.50, 0.29 and 0.21 after 18 days of storage at $4^{\circ}C$ and 0.38, 0.34 and 0.27, respectively, after 5 days of storage at $25^{\circ}C$. The acidity and turbidity changes of immersion solutions were sensitive to storage temperatures. The aerobic bacteria count of mulberry leaf soybean curds after 18 days of storage at $4^{\circ}C$ was still below $10^7\;CFU/g$, the beginning point of soybean curd putrefaction; in contrast, this value was reached within one day in distilled water at $25^{\circ}C$ and between 2 and 3 days in alkaline ionic water. Grapefruit seed extract and alkaline ionic water had a better preservative effect at $4^{\circ}C$ than at $25^{\circ}C$ storage temperature.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.1
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• pp.70-79
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• 2014

This study was conducted to develop natural additive for the improvement of lipid stability and the suppression of pathogenic contamination during the storage periods of fermented sausage. Fermented sausage prepared with grapefruit extract showed good suppression of lipid oxidation and pathogenic bacterial growth, and it was higher than that of fermented sausage prepared with nitrate until 7 days of storage. Fermented sausage prepared with treatment A (sodium nitrate and L. acidophilus), B (sodium nitrate and L. brevis), C (ascorbic acid and L. brevis) and D (grapefruit extract and L. brevis) were compared. As results, treatment C and D showed the lowest pH changes among treatments, and the highest growth of lactic acid bacteria was represented in treatment D. In the suppression effect of E. coli, the bacterial count was below 100 in all treatment except the treatment A. There were no differences among treatment in the brightness of meat color (p<0.05). Treatment D showed significantly high values in the redness, but showed the lowest values in the yellowness. In sensory and texture test, treatment C and D were superior compared to others. Therefore, grapefruit was represented as a good source of antioxidant for fermented sausage, and L. brevis isolated from kimchi was effect in lowering pH value of sausage during fermentation and it was also effective to persist fermentation during storage period and to reduce the occurrence of pathogenic bacteria by the suppression of their growth.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.1
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• pp.30-34
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• 2000

Salted Chinese cabbage was washed in 1,000 ppm solutions of grapefruit seed extract(GFSE) or citric acid, and used to make kimchi for the retentio of quality characteristics during fermentation at $10^{\circ}C$. Kimchi treated with GFSE or citric acid showed a retarded increase in titratable acidity and decrease in pH and reducing sugar content. Total microbial count and lactic acid bacteria of GFSE treated kimchi were about 1.1 log(CFU/g) lower than those of control and citric acid treated kimchi after making, but the difference was gradually reduced during fermentation.

• Food Science and Preservation
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• v.7 no.1
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• pp.8-11
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• 2000

The antimicrobial extracts of rheum palmatum and coptis chinensis root as well as grapefruit seed extract(GFSE) were applied to dipping treatment for keeping qualities of cucumbers, respectively, which were then packed in low density polyethylene(LDPE) films incorporated with 1 % antimicrobial extracts and stored $10^{\circ}C$. Dipping and packaging in the antimicrobial agents suppressed the growth of putrefactive microorgani는 and the decay ratio of cucumbers. In addition, the loss ratio of ascortic acid content and their weight was decreased during the sotrage of cucumbers. Consequently, the combined method of dippinf and packaging in antimicrobial agents turned out to be superior to dipping treatment or film-packaging in the view point of decay ratio and the keeping qualities of cucumbers.

• Journal of Microbiology and Biotechnology
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• v.30 no.12
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• pp.1854-1861
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• 2020

Staphylococcus aureus is one of the most common microorganisms and causes foodborne diseases. In particular, biofilm-forming S. aureus is more resistant to antimicrobial agents and sanitizing treatments than planktonic cells. Therefore, this study aimed to investigate the anti-biofilm effects of cell-free supernatant (CFS) of Saccharomyces cerevisiae isolated from cucumber jangajji compared to grapefruit seed extract (GSE). CFS and GSE inhibited and degraded S. aureus biofilms. The adhesion ability, auto-aggregation, and exopolysaccharide production of CFS-treated S. aureus, compared to those of the control, were significantly decreased. Moreover, biofilm-related gene expression was altered upon CFS treatment. Scanning electron microscopy images confirmed that CFS exerted anti-biofilm effects against S. aureus. Therefore, these results suggest that S. cerevisiae CFS has anti-biofilm potential against S. aureus strains.

• Korean Journal of Food Science and Technology
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• v.23 no.5
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• pp.614-618
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• 1991

To investigate the efficacy of grapefruit seed extract (GFSE) in the preservation of Satsuma mandarin, the citrus fruits were treated with 0 (control, only wash), 100 ppm and 250 ppm, dried and stored for 8 weeks at $15{\sim}20^{\circ}C$ and 60% RH. While 80% of the control fruits were contaminated and decayed by Penicillium sp., forming the the greenish blue spores, 27% of 100 ppm GFSE-treated fruits were contaminated and decayed and only 13% of 250 ppm GFSE-treated fruits were contaminated and decayed and only 13% of 250 ppm GFSE-treated samples were contaminated and not decayed by the fungi. GFSE showed marded inhibitory action against Penicillium sp. which was related to the decay of the citrus fruits in vitro experiments. Fungal growth was completely controlled through use of 500 ppm and the recommended range of GFSE to preserve the citrus fruits was $250{\sim}500ppm$. Transmission electron microscopic examination showed the fungal conidiospores the function of which was destroyed by dipping into GFSE.