In order to develop antimicrobial substances, many kinds of medicinal herbs were extracted with absolute ethanol and then antimicrobial activities against various microorganisms were investigated. Ethanol extract from cinnamon bark showed the strongest antimicrobial activity on the growth of almost all submitted microorganisms. Specially, molds such as Aspergillus sp. and Pencillium sp. were inhibited strongly. Therefore, the crude antimicrobial substance from the ethanol extract was fractionated with various solvents such as n-hexane, chloroform, ethyl acetate, and n-butyl alcohol and then their antimicrobial activities were tested. Among the various solvent fractions from the ethanol extract, n-hexane fraction was the best in antimicrobial activity especially against molds. There were no significant changes in antimicrobial activity of the n-hexane fraction by heat treatment at 100℃ for 60 min or 121℃ for 15 min and by the change of pH 4.0-10.0. We could get the results that the n-hexane fraction of cinnamon bark extract showed not only antimutagenicity but also no mutagenicity by Ames test with Salmonella typhimurium TA 98 and TA 100.

V. cholerae non-O1 49균주와 V. cholerae O1, V. mimicus, V. vulnificus와 V. parahaemolyticus의 균체지방산(fatty acid methyl ester; FAME)을 gas liquid chromatogrphy로 분석하였다. 이들 분석자료를 통계학적으로 처리하여 Vibrio 종과 V. cholerae의 혈청형별 유연성을 비교 검토하였다. 검출된 지방산은 모두 41종이었고 분포량이 많은 것은 16:0, 16:1 cis 9, 18:1 trans 9/16/cis 11과 15:0 iso 2 OH/16:1 cis 9 였다. 검출된 지방산 중에서도 35종은 V. cholerae를 동정하는데 주요한 인자로 작용되었다. 지방산분포를 UPGMA(비가중수리분석)으로 dendrogram을 작성한 결과 V. cholerae non-O1은 V cholerae O1보다 V mimieus가 더 높은 유사도를 나타내었다. 특히 hydoxy acid는 V. chozerae의 아종단위를 동정하는데 중요하였다. V. choEeore non-O1중에서 O2, O5, O8, O10, O14, O27, O37, O39, O45와 O69의 총 10 종류 혈청형을 대상으로 지방산 조성에 의 한 유사성을 검토한 결과 유사도가 92% 이상 수준에서 7개의 아종를 형성하여 혈청형과 지방산 조성간에는 유의할 만한 상관관계가 있었다. 따라서 V. cholerne non-O1의 동정 및 역학적인 조사시 지방산 분석은 유용하게 활용될 수 있음을 알 수 있었다.

Citrus펙틴을 효소로 가수분해시켜 얻은 펙틴분해물은 분해율이 35%가 되면서부터 항균력이 서서히 나타나기 시작하여 70% 이상에서는 급격히 증가하였으며 완전분해(100%)된 펙틴분해물을 배지에 2.0% 첨가하면 35℃에서 24시간까지 Escherichia coli ATCC l1229의 생육을 완전히 억제하였다. 펙틴분해물의 항균력은 pH 4.9~5.5 범위에서 가장 좋았으며 균종별로는 젖산균을 제외한 대부분의 세균에 대하여 강한 항균력을 나타내었고 젖산균과 곰팡이류에 대해서는 항균효과가 약하였으며 효모에 대하여는 전혀 영향을 미치지 않았다. 즉, 대부분의 세균은 펙틴분해물을 2.0~3.0% 첨가하므로써 35℃에서 48시간까지 생육이 완전히 억제되었으나, Lactococus lactis ATCC 19435, Lactobacillus bulgaricus, Penicllium funiculosum ATCC l1797은 대조구에 비하여 30~40%만이 억제되었으며 Saccharomyces formosensis와 Saccharomyces cerevisiae는 전혀 영향을 받지 않았다. 한편, glycine, ethanol, sodium ascorbate, sodium chloride 또는 sodium acetate 등의 화학보존료를 병용하면 펙틴분해물을 단독으로 사용하였을 때 보다 항균력이 상승하였다. 김치에 펙틴분해물을 1.0% 첨가하여 4℃에 저장하면 섭취하기에 알맞은 김치의 pH를 유지하는 기간이 대조구에 비하여 적어도 15일 이상 연장되었다. 또한 빵속에 펙틴분해물을 1.0%첨가하면 25℃에서 저장 4일째 대조구에 비하여 4 log cycles 그리고 저장 10일까지도 2 log cycles 정도 균의 성장이 억제되었다. 따라서, 펙틴분해물은 천연식품보존제로 이용가능하며 특히, 젖산균이나 효모에 대해서는 항균작용이 미약하거나 없으므로 젖산균이나 효모를 이용하는 발효식품의 품질보존제로서 아주 유용할 것으로 생각된다. 또한 기존의 화학보존료와 병용하므로써 화학보존료의 첨가량을 감소시킬 수 있다는 점에서도 유용하다고 생각된다.

Vibrio mimicus is a closely related species with V. cholerae, and has been reported to be associated with gastrointestinal infections. Although extraintestinal infections of these vibrios have also been reported in Japan and Southeast Asia. But little research papers on V. mimicus was reported in Korea. Therefore, we tried to isolate V. mimicus from the environmental sea water from April to July in Pusan, Korea. Among the isolated strains, we selected the strongest hemolytic strain and then named V. mimicus SM-9. In this paper, we checked the antibiotic susceptibility and psychrotrophic characteristics of the isolated strain. Hemolytic activity of the hemolysin produced by the isolated strain was also measured. V. mimicus was not detected from the sea water samples in April and May, but its detection rate was relatively high in June and July in Pusan, Korea. The bacteriological characteristics of V. mimicus SM-9 were Gram-negative rods, motile, oxidase positive, Voges-Proskauer negative and sucrose negative. In 23 kinds of antibiotics susceptibility test, V. mimicus SM-9 showed susceptibility to the most of antibiotics submitted while it was resistive against lincomycin, oxacillin, rifampin and vancomycin. Hemolytic activity of the hemolysin produced by V. mimicus SM-9 was highest in stationary phase of the growth curve in BHI broth at 37℃ and its activity was reached 18 HU per ml of culture supernatant. For checking the psychrotrophic property of V. mimicus SM-9, the decreasing rate of the strain in phosphate buffer solution and yellowtail flesh homogenate was examined during the storage at 4, 0, -4 and -20℃. The decreasing rates of the selected strain stored in phosphate buffer solution were greater than those in fish homogenate. Decreasing rates of V. mimicus SM-9 stored in phosphate buffer solution were not significantly different by the storage temperatures. The viable cell counts of the strain were decreased as 5 log cycles after 120 hours at all the tested temperatures. While decreasing numbers of the strain in fish homogenates were 2-4 log cycles after 120 hours. The decreasing pattern of the strain numbers were very slow after 200 hours at all the stored temperatures.

The ethanol extract from the root bark of Morus alba showed the strongest antimicrobial activity on the growth of almost all the tested microorganisms which were food-borne pathogens and food-related microorganisms. In order to isolate and purify of antimicrobial substance extracted from the root bark of Morus albs, the antimicrobial substance from the ethanol extract which exhibited a strong antimicrobial activity was purified by solvent fractionation, silica gel column chromatography, TLC and HPLC. Among the fractions fractionated by 4 kinds of solvents from the ethanol extract, the antimicrobial activity of ethyl acetate fraction had the strongest antimicrobial activity against B. subtilis. Unknown compounds were isolated from the ethyl acetate fraction by silica gel column chromatography, TLC and HPLC and the compounds showed strong absorbance at 207, 217 and 285 nm, therefore, it was supposed to be a kinds of aromatic compound.

The ethanol extract from the root bark of Mores alba showed the strongest antimicrobial activity on the growth of almost all the tested microorganisms which were foodborne pathogens d food-related microorganiama. Therefore, fatty acid composition, amino acid composition and shape change of microorganisms treated with the ethanol extract from the root bark of Mores alba were examined. In effects of treatment with the ethanol extract on the fatty acid compositions of B. aubtilis, S. aureus and E. coli, fatty aicd compositions such as hexadecanoic acid (16:0) and octadecanoic acid (18:0)/octadecadienoic acid (18:2) of the tested strains were increased but pentadecanoic acid (15:0), heptadecanoic acid (17:0) and octadecenoic acid (18:1) of E. subtilis, pentadecanoic acid (15:0) of S. ctureus and hexadecenoic acid (16:1) and octadecenoic acid (18:1) of E. coli were decreased. The ethanol extract did not significantly affect the amino acid composition of the tested strains. Tranamisaion electron micrographa of microorganisms treated with the ethanol extract exhibited morphological changes that irregularly contracted cell surface in S. aureus and destructed cell walls in B. subtilis and E. coli.

In order to develop a natural food preservative, the root bark of Morus alba was extracted with several solvents, and then antimicrobial activity was investigated. The optimum extracting condition for the antimicrobial substance from the sample, minimum inhibitory concentration (MIC) of the extracted substance against microorganisms were also examined. The antimicrobial activity of the ethanol extract from the sample was atronger than those of the extracts by the other solvents such as water, methanol, ethyl acetate and acetone. The optimum extracting condition for antimicrobial substance from the sample was shaking extraction twice for 5 hours at room temperature in case of 7 times of absolute ethanol added to the crushed root bark of Morus albs. The ethanol extract from the root bark of Mores albs had strong antimicrobial activity against Gram positive bacteria(MIC, 6.4-19.2 g/ml) such as B. subtilis, B. cereus, L. monocytogenes and S. aureus. Especially, Bacillus species was the most susceptible to the extracted substance. The ethanol extract showed antimicrobial activity against Gram negative bacteria(MIC, 160-1600 g/ml) and yeasts(MIC, 1600 g/ml) such as C. albicans and S. acidifaeciens. The extract also showed growth inhibition against molds such as A. niger, A. parasiticus, A. versicolar and T. uiride.

Bacteriocins from lactic acid bacteria have attracted much attention in recent years because of their useful worth in increasing safety and extending shelf life of foods. These substances show an inhibitory effect against some food spoilage bacteria and food-borne pathogens. The inhibitory effect of the bacteriocin produced by lactic acid bacteria against Listeria monocytogenes(L. monocytogenes) was examined in this study. The culture supernatants of 5 kinds of bacteria among the 10 kinds of tested lactic acid bacteria had the inhibitory activity against Listeria sp., various Gram positive and Gram negative bacteria. Bacteriocin produced by Lactobacillus plantarum(Lact. plantarum) LMG 7945 was the most active toward L. monocytogenes. Bacteriocin production of the Lact, plantarum LMG 7945 cultured on MRS broth was increased late logarithmic phase over early stationary phase. This bacteriocin was stable at heat treatment and acidic pH relatively; The activity was retained after heating at 121 for 15min and was active in the pH range of 2-4 but was lost above pH 5.

The effect of the ethanol extract from salviae miltiorrhizae radix (Salvia miltiorrhiza) on the microbial growth and the stability of the extracted antimicrobial material were investigated. The ethanol extract had strong growth inhibition activity (MIC, 3.13-50.0 pg/ml) against Gram-positive bacteria such as B. subtilis, L. monocytogenes and S. aureus. Among Gram-positive bacteria tested, B. subtilis was the most susceptible to the extracted substance. While the antimicrobial activity of the ethanol extract was weak (MIC, 400-800 ug/ml) to E. coli and yeasts (C. albicans. Sacch. diastaticus). The ethanol extract had bactericidal action at higher concentration than MIC against B. subtilis, while the extract had only bacteriostatic action against S. aureus. The extracted antimicrobial substance was stable in the pH range of 4.0 to 10.0, heat treatment at 121℃ for 15 min, and freezing and thawing