• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.139-143
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• 2005

We evaluated grapefruit seed extract for antibacterial activity at varying time intervals and concentration levels against heat tolerant and spore-forming Bacillus stearothermophilus, mesophilic Bacillus subtilis, and food poisoning Staphylococcus aureus. Grapefruit seed extract showed growth inhibitory activity against B. stearothemophilus and B. subtilis, and S. aureus at the level of 0.01 tp 0.03% in nutrient broth. However, when applied to soymilk in a market, grapefruit seed extract at the level above 0.2% effectively inhibited the growth of B. stearothermophilus, However, it failed to completely sterilize the test organisms. On the other hand, B. subtilis and S. aureus were completely sterilized at the level of 0.2% within 48 hrs and 72 h, respectively. The higher concentration of grapefruit seed extracts showed more effective antibacterial activities against the test organisms, but caused deteriorated organoleptic quality and emulsion stability. We could conclude, by applying grapefruit seed extract (0.015%) with thermal treatment (10 min at $121^{\circ}C$) that the microbial stability of commercial soymilk was enhanced greatly.

• The Korean Journal of Food And Nutrition
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• v.19 no.4
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• pp.526-531
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• 2006

Minimum inhibition concentration(MIC), growth inhibition activity, and colony forming inhibitory activity of grapefruit seed extract against Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Escherichia coli, Salmonella enterifidis and Serratia marcescens were tested. MIC of grapefruit seed extract against Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Escherichia coli, Salmonella enteritidis and Serratia marcescens was 12.5, 12.5, 12.5, 50, 50, 100ppm, respectively. Growth inhibition concentration of grapefruit seed extract against Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Escherichia coli, Salmonella enteritidis and Serratia marcescens was below 1.0, 6.25, below 1.0, 6.25, 25, 25ppm, respectively. Colony forming inhibitory activity of grapefruit seed extract against Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Escherichia coli, Salmonella enteritidis and Serratia marcescens was 93.9, 94.0, 99.9, 4.4, 82.7, 86.4%, respectively. Colony forming inhibitory activities of grapefruit seed extract against Gram positive bacteria were higher than that against Gram negative bacteria.

• Journal of Food Hygiene and Safety
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• v.7 no.1
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• pp.15-22
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• 1992

This study was conducted to determine the potential of grapefruit seed extract to support Aspergillus parasilicus growth and aflatoxin production. The grapefruit seed extract inhibited the growth and aflatoxin production of the fungi in the level of more than 4,000 ppm and 3,000 ppm in the medium, respectively. Grapefruit seed extract appears to block the conversion of acetate, averufin and versiconal acetate into aflatoxin in vitro experiments. The addition of grapefruit seed extract to the feeding experiment systems did not inhibit the incorporation of 14C-labeled versicolorin A, versicolorin A hemiacetal and sterigmatocystin into aflatoxin. In the electron microscopic examination the biocidal action of grapefruit seed extract was related to the disturbance of cell menbrane funtion, inhibiting cellular respiration.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.5
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• pp.690-694
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• 1995

Effects of grapefruit seed extract on the lethality, the primary skin irritation, and the acute eye irritation potentials were evaluated in rats. The acute oral $LD_{50}$ of GFSE for Sprague-Dawley derived rats was 3.75g/kg with 95% confidence limits of 2.55 and 5.52g/kg. Patch application to the intact and abraded skin of rabbits led to mild to moderate erythema and no or mild edema. Application to the eyes of rabbits led to severe corneal opacity, iritis, conjunctival erythema, edema, and discharge.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.6
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• pp.1086-1093
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• 1998

The antimicrobial effect of mixed solutions of grapefruit seed extract(250ppm) and ascorbic acid(1%) on the spoilage microorganisms such as Staphylococcus epidermis, Escherichia coli, Pseudomonas syringae, Candida albicans and Corynebacterium xerosis isolated from the spoiled soybean sprouts were investigated. Cell wall and membrane were partially destroyed and the contents of the destroyed cell were exuded after treatment. Packages with 30 m cast polypropylene(CPP), 16 m polyolefin(RD 106) and 10 m high density polyethylene(HDPE) were applied for soybean sprouts dipped in mixed solutions respectively. Oxygen and carbon dioxide concentration inside packages were dependent on the kind of films during storage at 5oC. The antimicrobial activity of mixed solutions was maintained for 5 days at CPP package. Package with HDPE showed a severe browning than the others after 5 days. Ascorbic acid content of mixed solution treatment was higher than that of control for each package.

• Food Science and Preservation
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• v.13 no.2
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• pp.168-173
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• 2006

To investigate the effect of grapefruit seed extract pretreatment and packaging materials on the quality of dried persimmon, dried persimmons were stored for $60{\sim}100$ days at room temperature $(15^{\circ}C)$ after dipping in grapefruit seed extract and then packing with LDPE (low density polyethylene) film and Nylon/LDPE film pouch $(30{\times}30cm^2)$. Weight loss of dried persimmon packaged with Nylon/LDPE film was not exceeded 86% of control. 60% mold occurrence and 50% browness were observed compared to control. There were no significant differences in the firmness, soluble solid content and color between grapefruit seed extract pretreatment and control. Grapefruit seed extracts pretreatment had an effect on the inhibition of color change in Hunters value.

• Food Science and Preservation
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• v.1 no.1
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• pp.1-7
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• 1994

To investigate the effect of several bactericides and fungicides against fruit & vegetable decay grapefruit seed extract(GFSE) was tested in a dilution solution. GFSE was shown to be effective against decay and rind breakdown and to extend the shelf-life of fruits and vegetables during storage and tiansport. Antimicrobial efficiency of GFSE on a wide spectra of gram + & - bacteria, moulds and yeasts was demonstrated by the measurement of minimal inhibitory concentrations performed (Bacteria 10-500ppm, Fungi:250-1,000ppm, Yeasts:100-250ppm). GFSE was separated and extracted into water-soluble fraction, water-insoluble and non-dialyzed fraction to isolate the antimicrobial substances. The water-soluble fraction showed the most active antimicrobial effect. The antimicrobial substances were isolated by gas chromatography. As the result of the isolation using GC, Peak-D was found to be the antimicrobial compound in GFSE. The identification of the most antimicrobial substance was carried out by using GC-MS.

• Journal of Food Hygiene and Safety
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• v.10 no.1
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• pp.33-39
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• 1995

The antibacterial and antifungal effect of grapefruit seed extract(GFSE) was investigated for its purpose of application to a diverse spectrum of field as sanitizers, disinfectants and preservatives. GFSE showed coparatively high content of such flavoniods as naringin and hesperidin and ascorbic acid. GFSE containing a low level of organic acids is a heavy viscous and water-soluble liquid. As a result of the antimicrobial test of GFSE, Bacillus subtilis and Aspergillus oryzae did not survive at detectable levels when treated with more than 100 ppm of GFSE. The minimum inhibitory concentrations of GFSE for a wide variety of pathogenic and putrefactive bacteria, fungi and yeasts were 100 ppm and 250 ppm, respectively. In the comparable electron micrograph of microbial cells treated with GFSE or not, we could conclude that GFSE destroy microorganisms by disrupting the functions of the cell wall membrane and microbial spores.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.6
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• pp.948-956
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• 2013

This study investigated methods to improve the quality of Topokkidduk using grapefruit seed extracts and acid regulation agents. Topokkidduk was investigated in terms of its moisture, color, pH, texture, microbial composition, and sensory properties. The moisture content of Topokkidduk was highest for Topokkidduk supplemented with grapefruit seed extracts. The color of Topokkidduk (the L value) decreased, whereas the "a" value increased with the addition of grapefruit seed extracts. The texture of Topokkidduk was affected more by additives than storage temperature. The addition of grapefruit seed extracts and acid regulation agents were effective for the inhibition of microbial activity in Topokkidduk during storage. The overall acceptability values of Topokkidduk (without supplements) were highest among the samples. These results suggest that grapefruit seed extracts and acid regulation agents can be used to control microbial load and moisture levels in Topokkidduk.

• Journal of Food Hygiene and Safety
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• v.9 no.3
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• pp.141-149
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• 1994

To investigate the distribution of Vibrio parahaemopyticus in the southern 4 coastal areas, Vibrio parahaemolyticus was isolated from seawater, shellfish and sediment from May to October in 1991, and antimicrobial effect of grapefruit seed extract (GFSE) on the growth of isolated strains were examined. In the 120 sample from 4 coastal areas, 16 strains of Vibrio parahaemolyticus were isolated and identified. The distribution serotype of isolated strains was 10 types of monovalent k-antiserum. Especially k-5 and k-28 were highly distribyted with 3 and 4 strains. 31.3% of isolated strains showed positive on Kanagawa phenomenon test. All isolated Vibrio parahaemolyticus were sensitive to chloramphenicol and gentamycin, 5 and 6 strains were resistant to streptomycin and colistin, respectively. Isolated strains were compared with geographical, month and sample. The distribution of 16 isolated Vibrio parahamolyticus was high at Hadong with 50%(8 strains), on July with 43.8%(7 strains) and from seawater with 37.5%(6 strains) respectively. Minimal inhibitory level of GFSE to Vibrio parahaemolyticus was 50 ppm. With 100 ppm treatment of GFSE, the destroy of cell membrane function, outflow of cell ingredients and ghost morphology of cell were investigated.