• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.4
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• pp.600-607
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• 2013

This study was performed to investigate the repeated-dose toxicity of Leuconostoc citreum GR1 (Leuc. citreum GR1), a lactic acid bacterium isolated from kimchi, in male and female rats. Sprague-Dawley male and female rats were divided into four group (ten animals in each group) and Leuc. citreum GR1 was administered daily by gavage to rats at dosage levels of 0, 500, 1,000, or 2,000 mg/kg/day for four weeks. There were no bacterial-related deaths or abnormal clinical signs in either gender of rats during the observation period. Furthermore, no differences were found between the control and treatment groups in terms of body weight, food intake, and water consumption. Hematological parameters, serum biochemical analysis, and histopathological examination also showed insignificant dose-dependent alterations. There were also no alterations in organ weights upon administration of Leuc. citreum GR1 alone. These results suggest the oral application of Leuc. citreum GR1, up to a dosage level of 2,000 mg/kg, causes no adverse effects in both male and female rats.

• Food Science and Preservation
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• v.20 no.1
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• pp.121-126
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• 2013

The present study was carried out to investigate the in vivo single-dose acute toxicity of Leuconostoc citreum GR1 (Leuc. citreum GR1), a lactic acid bacteria isolated from kimchi, in ICR male and female mice. The test article was orally administered once to both sexes of mice. The mortalities, clinical findings, autopsy findings, and body weight changes were monitored daily for two weeks. The male and female mice were gavaged with Leuc. kimchi GR1 of four doses (625, 1,250. 2,500 and 5,000 mg/kg). The oral $LD_{50}$ of Leuc. citreum GR1 was considered higher than 5,000 mg/kg. No significant changes in the general conditions, body weights, clinical signs and presence of gross lesions were observed in both sexes of mice to whom Leuc. citreum GR1 was administered orally. The results indicated that the 5,000 mg/kg dose of Leuc. citreum GR1 showed no adverse effect.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.7
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• pp.1125-1132
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• 2013

In the kimchi manufacturing process, the starter is cultured on a large-scale and needs to be supplied at a low price to kimchi factories. However, current high costs associated with the culture of lactic acid bacteria for the starter, have led to rising kimchi prices. To solve this problem, the development of a new medium for culturing lactic acid bacteria was studied. The base materials of a this novel medium consisted of Chinese cabbage extract, a carbon source, a nitrogen source, and inorganic salts. The optimal composition of this medium was determined to be 30% Chinese cabbage extract, 2% maltose, 0.25% yeast extract, and $2{\times}$ salt stock (2% sodium acetate trihydrate, 0.8% disodium hydrogen phosphate, 0.8% sodium citrate, 0.8% ammonium sulfate, 0.04% magnesium sulfate, 0.02% manganese sulfate). The newly developed medium was named MFL (medium for lactic acid bacteria). After culture for 24 hr at $30^{\circ}C$, the CFU/mL of Leuconostoc (Leuc.) citreum GR1 in MRS and MFL was $3.41{\times}10^9$ and $7.49{\times}10^9$, respectively. The number of cells in the MFL medium was 2.2 times higher than their number in the MRS media. In a scale-up process using this optimized medium, the fermentation conditions for Leuc. citreum GR1 were tested in a 2 L working volume using a 5 L jar fermentor at $30^{\circ}C$. At an impeller speed of 50 rpm (without pH control), the viable cell count was $8.60{\times}10^9$ CFU/mL. From studies on pH-stat control fermentation, the optimal pH and regulating agent was determined to be 6.8 and NaOH, respectively. At an impeller speed of 50 rpm with pH control, the viable cell count was $11.42{\times}10^9(1.14{\times}10^{10})$ CFU/mL after cultivation for 20 hr - a value was 3.34 times higher than that obtained using the MRS media in biomass production. This MFL media is expected to have economic advantages for the cultivation of Leuc. citreum GR1 as a starter for kimchi production.