Korean Fermented Food Research Articles

Autoinducer-2 associated inhibition by Lactobacillus sakei NR28 reduces virulence of enterohaemorrhagic Escherichia coli O157:H7

Abstract Bacteria use quorum sensing (QS) to regulate the expression of certain target genes for social behaviour. A LuxS/AI-2 signalling system serves to control the virulence of some pathogenic bacteria by mechanisms such as motility, biofilm formation and attachment, and is typical of the enterohaemorrhagic Escherichia coli O157:H7 (EHEC) associated with infections of the human intestine. The LuxS/AI-2 signalling system presents an interesting potential as antimicrobial target for appropriate AI-2 inhibitors, and thus widens the scope for treatment or prevention of infections by pathogens such as EHEC. Probiotic lactic acid bacteria (LAB) are primary candidates for this approach because of their general acceptability, safety and adaptation to the intestinal and/or food ecosystem. In this paper, we report on Lactobacillus sakei NR28 as a new candidate strain for AI-2 related quorum quenching. It is considered to be a putative probiotic strain and was originally isolated from kimchi, a traditional Korean fermented food known for its special health features. This study has shown that AI-2 activity and the associated virulence factors of the EHEC ‘wild-type’ strain E. coli ATCC 43894, were significantly reduced by L. sakei NR28, while, at the same time, the cell viability of the EHEC strain was not affected. In addition, the purified AI-2 molecule, a luxS-deficient mutant of EHEC strain ATCC 43894, and an AI-2 independent EHEC mimicking strain of Citrobacter rodentium were used to determine the relationship between the virulence reducing effect of L. sakei NR28 and its AI-2 inhibiting ability. Our results showed that L. sakei NR28 has a reducing effect on the pathogenicity of the ‘wild-type’ EHEC strain ATCC 43894 by AI-2 signalling inhibition.

Characterization of a glutamate decarboxylase (GAD) gene from Lactobacillus zymae.

Lactic acid bacteria (LAB) were isolated from Kimchi, a Korean traditional fermented vegetable food. LAB accumulating GABA (γ-aminobutyric acid) in the culture media were screened by TLC analysis. One isolate, GU240, produced the highest amount of GABA among the 3,000 isolates and identified as a Lactobacillus zymae strain. Glutamate decarboxylase (GAD) gene was cloned and over-expressed in E. coli BL21(DE3) using pET26b(+). The recombinant GAD was purified by using a Ni-NTA column. Its size was 53kDa by SDS-PAGE. Maximum GAD activity was at pH 4.5 and 41°C and the activity was dependent on pyridoxal 5'-phosphate. Km and Vmax of LzGAD were 1.7mM and 0.01mM/min, respectively, when glutamate was used as a substrate.

Improved production of poly-γ-glutamic acid by Bacillus subtilis D7 isolated from Doenjang, a Korean traditional fermented food, and its antioxidant activity.

The objectives of this study was to improve poly-γ-glutamic acid (γ-PGA) production by Bacillus subtilis D7 isolated from a Korean traditional fermented food and to assess its antioxidant activity for applications in the cosmetics and pharmaceutical industries. Strain D7 produced γ-PGA in the absence of L-glutamic acid, indicating L-glutamic acid-independent production. However, the addition of L-glutamic acid increased γ-PGA production. Several tricarboxylic acid cycle intermediates and amino acids could serve as the metabolic precursors for γ-PGA production, and the addition of pyruvic acid and D-glutamic acid to culture medium improved the yield of γ-PGA markedly. The maximum yield of γ-PGA obtained was 24.93 ± 0.64g/l in improved medium, which was about 5.4-fold higher than the yield obtained in basal medium. γ-PGA was found to have 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (46.8 ± 1.5%), hydroxyl radical scavenging activity (52.0 ± 1.8%), 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonate (ABTS) radical scavenging activity (42.1 ± 1.8%), nitric oxide scavenging activity (35.1 ± 1.3%), reducing power (0.304 ± 0.008), and metal chelating activity (91.3 ± 3.5%). These results indicate that γ-PGA has a potential use in the food, cosmetics, and biomedical industries for the development of novel products with radical scavenging activity. As far as we are aware, this is the first report to describe the antioxidant activityof γ-PGA produced by bacteria.

Leuconostoc citreum 61 isolated from Kimchi, a Korean traditional food, decreases IgE synthesis via suppression of non‐antigen‐specific B cell responses (LB353)

Allergic diseases are described as immunological conditions characterized by an increased synthesis of IgE with a predominance of Th2 cells over Th1 cells. Consumption of food containing microorganisms is encouraged to restore the imbalance of Th 1 and Th2 cells. The objective of this study is to evaluate immunomodulatory effects of some strains among Leuconostoc citrum (LC) species isolated from Kimchi, a traditional Korean fermented food. After screening, we chose LC 61 and LC 64, which were identified and designated by our laboratory, for their ability to induce strong responses in tumor necrosis factor‐alpha and interleukin (IL)‐12 secretion by mouse peritoneal macrophages. When mouse splenocytes were incubated with these strains under the Th2 polarizing conditions in which anti‐CD3 antibody and recombinant IL‐4 were added into the culture media, a six to seven fold higher level of interferon (IFN)‐gammaγwas observed but with little effect on IL‐4. Further, we examined the ability of LC 61 to regulate the aberrant Th2 response in vivo using the ovalbumin (OVA)‐induced allergy model. Oral feeding began 2 weeks before the sensitization and challenge of OVA and continued throughout the experimental period. Mice fed LC 61 showed a reduced level of total IgE, but not OVA‐specific IgE, in serum. CD40 (+) cells in the spleen from LC treated mice increased but there was no change in the population of CD4(+), CD8(+), and CD19(+) cells, indicating that LC 61 favored antigen presenting cells that belong to innate immunity. Of note, LC 61 significantly increased the population of CD19(+)CD80(‐) cells accompanied by a decrease in the population of CD19(+)CD80(+) cells. Upon OVA restimulation, splenocytes from LC 61 treated mice showed increased levels of IFN‐gammaγand IL‐4. From our results, the anti‐allergic effect of LC 61 seems to be mediated by the suppression of bystander B cell, and possibly T cell too, activation required for IgE synthesis, not by the modulation of allergen‐specific responses. We provide evidence that LC 61 isolated from Kimchi can be a beneficial probiotic strain for restoring the dysregulated Th1 and Th2 immune responses.

된장으로부터 분리된 Bacillus subtilis CBD2의 생육특성 및 amylase 활성

In this study, one GRAS strain was screened from doenjang, a traditional Korean fermented food, as a microorganism producing amylase due to the formation of a clear zone on the medium including soluble starch. From the analysis of the gene sequence of 16S ribosomal RNA, the strain was identified as Bacillus subtilis and was therefore named Bacillus subtilis CBD2. When the nutrient broth medium was prepared with 3% NaCl, 5% glucose, and the initial medium pH 7.0, the B. subtilis CBD2 showed maximum growth. Among soluble starch, corn starch, maize amylopectin, and wheat starch, soluble starch was the most effective carbon source in the production of amylase by B. subtilis CBD2. The amylase from B. subtilis CBD2 showed the highest activities at pH 8.0 and 50°C, and corn starch was the most proper substrate for the enzyme activity. When corn starch was used as a substrate, the production of sugars through enzyme activity increased for 24 h, and then the enzyme activity became constant.

아밀로이드 베타에 의해 유도된 인지 및 기억능력 손상에 대한 김치의 보호 효과

Kimchi is a Korean traditional fermented food with various health functionalities. However, the protective effects of kimchi against Alzheimers disease (AD) have not been studied yet. In this study, the protective activities of kimchi extract against oxidative stress and AD were investigated in an amyloid beta (Aβ)-induced AD model using ICR mice. Kimchi extract exerted strong scavenging activities against 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radical. In addition, T-maze, object cognition, and water maze tests were carried out using the AD model. The Aβ 25-35 -injected groups showed impairment of cognition and memory. However, the abilities of novel object recognition and new route awareness were improved by administration of kimchi extract (100 and 200 mg/kg/day) for 2 weeks. Furthermore, the results on water maze test indicated that kimchi extract exerted protective activity against cognitive impairment induced by Aβ 25-35 . The present study suggested that kimchi protected against Aβ-induced impairment of memory and cognition as well as attenuated oxidative stress.

Safety Assessment of Starters for Traditional Korean Fermented Foods

Most microorganisms have been used for foods for such a long period of time with no question posed for their safety. However, the progress of food processing technology has activated international food trades, and the consumers and authorities of import countries have come to question the safety of microorganisms used in foods. At present, the most widely known safety standards are Generally Recognized as Safe (GRAS) status from the US Food and Drug Administration (FDA) and Qualified Presumption of Safety (QPS) status by the European Food Safety Authority (EFSA). GRAS status is not for the safety of microorganisms themselves but for the permissibility of strains or cultures in specific food uses. QPS provides a qualified generic approval to a defined taxonomic unit. The increase of commercialized traditional fermented foods in Korea has spurred the starter development for traditional food fermentations. However, starter development in Korea has been carried out based on the technological properties of microorganisms with no research on developing a standardized tool for safety assessment. In the globalization of traditional Korean fermented foods, technological properties as well as safety of future starters should be guaranteed, and establishment of the safety assessment regulation for microorganisms used for foods is necessary.

Microbial diversity in Korean fermented foods by using molecular biological tools

Microbial diversity in Korean fermented foods by using molecular biological tools

CheonggukjangEthanol Extracts Inhibit a Murine Allergic Asthma via Suppression of Mast Cell-Dependent Anaphylactic Reactions

Cheonggukjang (CGJ), a traditional Korean fermented soybean food, exerts immunomodulatory effects. Asthma is the most common chronic allergic disease to be associated with immune response to environmental allergens. In the pathogenesis of asthma, histamine is one of the important inflammatory mediators released from granules of mast cells. In this study, we evaluated the therapeutic effect of CGJ on a mouse model of ovalbumin (OVA)-induced asthma via the suppression of histamine release. C57BL/6 mice were sensitized by intraperitoneal injection of OVA or a phosphate-buffered saline (PBS) control and then challenged with OVA inhalation. Mice were treated intraperitoneally with either 70% ethanol-extracted CGJ (CGJE) (100 mg/kg/day) or equivalent PBS. Asthma-related inflammation was assessed by bronchoalveolar lavage fluid cell counts and histopathological and immunohistochemical analysis of lung tissues. To elucidate the mechanisms of asthma inhibition by CGJE treatment, we also examined degranulation and histamine release of compound 48/80-induced rat peritoneal mast cells (RPMCs). Treatment with CGJE downregulated the number of eosinophils and monocytes in the lungs of mice challenged with OVA and suppressed histopathological changes, such as eosinophil infiltration, mucus accumulation, goblet cell hyperplasia, and collagen fiber deposits. Moreover, CGJE alleviated compound 48/80-induced mast cell degranulation and histamine release from RPMCs through inhibition of calcium (Ca²⁺) uptake as well as ear swelling by infiltration of inflammatory cells. These findings demonstrated that CGJE can be used as an antiasthmatic dietary supplements candidate for histamine-mediated asthma.

Genome sequence of the chromate-resistant bacterium Leucobacter salsicius type strain M1-8(T.).

Leucobacter salsicius M1-8T is a member of the Microbacteriaceae family within the class Actinomycetales. This strain is a Gram-positive, rod-shaped bacterium and was previously isolated from a Korean fermented food. Most members of the genus Leucobacter are chromate-resistant and this feature could be exploited in biotechnological applications. However, the genus Leucobacter is poorly characterized at the genome level, despite its potential importance. Thus, the present study determined the features of Leucobacter salsicius M1-8T, as well as its genome sequence and annotation. The genome comprised 3,185,418 bp with a G+C content of 64.5%, which included 2,865 protein-coding genes and 68 RNA genes. This strain possessed two predicted genes associated with chromate resistance, which might facilitate its growth in heavy metal-rich environments.

한국 전통 발효식품에서 분리한 인산가용화 효모의 특성

한국 전통 발효식품에서 분리한 효모로부터 인산 가용화 활성이 우수한 5균주를 선발하였다. 선발한 균주 중 2균주는 Pichia anomala로 동정되었고, 3균주는 각각 Pichia farinosa, Candida versatilis, Pichia subpelliculosa로 동정되었다. 인산 가용화 효모는 <TEX>$20{\sim}35^{\circ}C$</TEX>의 온도에서 잘 자라는 중 온성 효모였으며 P. farinosa Y669는 <TEX>$45^{\circ}C$</TEX>의 고온에서도 생장하였다. C. versatilis Y907 균주는 pH 5~6의 좁은 pH 범위에서 생장하였고 15%의 NaCl 농도까지 내성을 나타내는 호염성 균주였다. 그 외 4균주는 pH 4.0~8.0에서 생장하였으며 NaCl 10% 농도에서 내성을 나타내었다. 인산 가용화 균주는 토양에서도 8주 동안 <TEX>$10^7{\sim}10^8$</TEX> cfu/g의 밀도를 유지하며 생존하였다. 분리균주 중 인산 가용화 활성은 P. subpelliculosa Y1101가 가장 우수하였으며 배양 11일 후 697.2 ug/mL의 유리인산을 생성하였다. Of 1,100 yeast strains which were isolated from various Korean fermented foods, screened for phosphate solubilization, five strains showed the ability to solubilize tricalcium phosphate. The 26S rDNA domain D1-D2 sequence analysis revealed the identification of strain Y393 and Y524 as Pichia anomala (99.8 and 100% identity, respectively), Y669 as Pichia farinosa (100% identity), Y901 as Candida versatilis (100% identity), and Y1101 as Pichia subpelliculosa (100% identity). All the phosphate solubilizing strains showed mesophilic characteristics. The temperature range for growth of 4 strains was <TEX>$20{\sim}35^{\circ}C$</TEX> and P. farinosa Y669 was able to grow up to <TEX>$45^{\circ}C$</TEX>. The strain C. versatilis Y907 was able to grow at pH range of 5.0~6.0 and showed halophilic characteristics with tolerance to 15% of NaCl concentration. The Phosphate solubilizing yeast strains were survived well in bed soil for 8 weeks which were maintained densities of <TEX>$10^7{\sim}10^8$</TEX> cfu/g. The highest phosphate solubilizing activity was observed in P. subpelliculosa Y1101. It solubilized 697.2 ug/mL of phosphorus from tricalcium phosphate with decrease in pH from 6.8 to 4.37 after 11 days of inoculation.

Characteristics and immuno-modulatory effects of Weissella cibaria JW15 isolated from Kimchi, Korea traditional fermented food, for probiotic use

In this study, characteristics and immuno-modulatory effects of Weissella cibaria JW15 isolated from Kimchi, traditional Korean fermented food, were examined for investigation of the capacity of potentially probiotic strains. We measured acid, bile, and heat tolerance, adhesive properties to intestinal epithelial cells, and inhibitory activity against pathogens. JW15 could survive at pH 3.0 for 2 hr, but not at pH 2.0. JW15 also showed tolerance to 0.3% oxgall bile salt, and heat tolerance at 70°C and 80°C for 5 min, respectively. Adhesive ability to Caco-2 cells was similar to that of Lactobacillus rhamnosus GG (LGG), a well-known commercial probiotic. JW15 exhibited antimicrobial activities to pathogenic bacteria such as Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, and Salmonella enteritidis. The immuno-modulatory effects of JW15 were compared with those of LGG, a well-known immune enhancer. For analysis, production of nitric oxide (NO), NF-κB (Nuclear factor κB), Interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) was measured. The concentration of NO induced by JW15 was higher than that by LGG at low concentration (1 × 10 7 cfu/mL). Low and high (5 × 10 7 CFU/mL) concentration of JW15 induced statistically higher production of NF-κB, IL-1β, and TNF-α than that produced by LGG, respectively. In conclusion, Weissella ci\-baria JW15 had ability as a probiotic strain, including acid, bile, and heat tolerance, adhesive properties to intestinal epithelial cells, and inhibitory activity against pathogens. In addition, JW15 showed better immuno-modulatory effects than LGG when NO, NF-κB, IL-1β, and TNF-α were measured. According to these results, the characteristics and immunomodulating activity of Weissella cibaria JW15 are suitable for consideration as a potential probiotic.

In vitro antifungal, probiotic and antioxidant properties of novel Lactobacillus plantarum K46 isolated from fermented sesame leaf

This study aimed to describe the diversity of antifungal lactic acid bacteria (LAB) in popular traditional Korean fermented food. A total of 22 LAB strains was selected and subjected to a monophasic identical approach using 16S rRNA gene sequence analysis. Antifungal LAB associated with fermented food was identified as Lactobacillus plantarum (9), Lactobacillus graminis (5), Lactobacillus pentosus (4), Lactobacillus sakei (2), Lactobacillus paraplantarum (1), and Leuconostoc mesenteroides subsp. mesenteroides (1). Novel Lactobacillus plantarum strain K46 exhibited comparatively better antifungal activity against several spoilage fungi, and was deposited in the Korean Collection for Type Cultures (KACC91758P). Antifungal substances from the spent medium in which K46 was cultivated were extracted with ethyl acetate. Antifungal activity was assessed using the broth micro dilution technique. Compounds were characterized based on infrared, 13C nuclear magnetic resonance (NMR), and 1H NMR spectral data. The minimum inhibitory concentration (MIC) of the compounds against Aspergillus clavatus, Aspergillus oryzae, Penicillium chrysogenum and Penicillium roqueforti was 2.5 mg/mL and that against Aspergillus fumigatus, Aspergillus niger, Curvularia lunata and Gibberella moniliformis was 5.0 mg/mL. K46 was able to survive gastrointestinal conditions simulating the stomach and the duodenum passage with the highest percentage of hydrophobicity. In addition, its resistance to hydrogen peroxide and highest hydroxyl radical and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities, with inhibition rates of 43.53 % and 56.88 %, respectively, were to its advantage. An antimicrobial susceptibility pattern was an intrinsic feature of this strain, thus consumption does not represent a health risk to humans. The results showed the potential of K46 strain as an antifungal, probiotic and antioxidant culture, and hence it was determined to be suitable for application in functional foods.

Cyclic dipeptides from lactic acid bacteria inhibit proliferation of the influenza a virus

We isolated Lactobacillus plantarum LBP-K10 from the traditional Korean fermented food kimchi. When organic acids were removed, the culture filtrate of this isolate showed high antiviral activity (measured using a plaque-forming assay) against the influenza A (H3N2) virus. Two fractions that were active against influenza A virus were purified from the culture filtrate using a C18 column with high-performance liquid chromatography. These active fractions were crystallized and identified to be the cyclic dipeptides cis-cyclo (L-Leu-L-Pro) and cis-cyclo(L-Phe-L-Pro) using gas chromatography-mass spectrometry; this identification was confirmed by X-ray crystallography. These cyclic dipeptides were identified in the culture filtrate of other lactic acid bacteria, including Lactobacillus spp., Leuconostoc spp., Weissella spp., and Lactococcus lactis.

젖산 생성능이 우수한 김치 유래 젖산균의 분리 및 두유 발효 특성

Lactic acid bacteria were selected on the basis of lactic acid producing ability from kimchi, a traditional Korean fermented food. Among the initial screening of over 150 strains selected from the sample, 27 strains were selected as lactic acid producing bacteria, and 4 strains were finally selected based on their ability to produce relatively high levels of lactic acid. The four strains were identified as Lactobacillus (L.) plantarum Gk04, Pediococcus pentosaceus Gk07, L. brevis Gk35 and L. curvatus Gk36 by the conventional morphological, cultural, physiological and biochemical characteristics, as well as by 16S rRNA sequence analysis. Among the identified lactic acid bacteria, L. curvatus Gk36 was used for soymilk fermentation. The viable cell counts and acidity values measured for the L. curvatus Gk36 were comparable to the commmercial L. acidopillus. Thus, the L. curvatus Gk36 is a potential probiotic strain to prepare fermented soy products, such as kephir, yogurt, tempeh and soy sauce.

Production of γ-Aminobutyric Acid by Lactobacillus brevis 340G Isolated from Kimchi and Its Application to Skim Milk

The Lactobacillus brevis 340G strain isolated from traditional Korean fermented food (kimchi) produced 15.50mMof γ-aminobutyric acid (GABA) after 48 h of cultivation in MRS media containing 1% L-monosodium glutamate(MSG). The culture conditions of Lb. brevis 340G were optimized for GABA production. Lb. brevis 340G was cul-tivated at 30oC in optimized MRS media containing 3% sucrose and 2% yeast extract with 3% MSG, resulting inmaximum GABA production (68.77mM) after 54 h of cultivation. Skim milk fermented with Lb. brevis 340G pro-duced 4.64mM of GABA in the presence of 1% MSG. These results suggest that Lb. brevis 340G could be usedas a starter for functional fermented foods and skim milk fermented with Lb. brevis 340G could be further devel-oped to become functional dairy food fortified with GABA.

Behavior of flavonoid glycosides contained in Korean red pepper paste (Gochujang) during fermentation: Participation of a β-glucosidase inhibitor

Gochujang is a red pepper-soybean paste and a popular Korean fermented food. The aim of this study was to investigate the behavior of flavonoids and activity of β-glucosidase during fermentation of gochujang prepared using Aspergillus oryzae. The content of flavonoid glycosides (genistin, daidzin, apigenin 7-O-β-d-glucopyranoside, and quercetin 3-O-α-l-rhamnopyranoside) and their aglycones did not change significantly during preparation of gochujang. However, β-glucosidase was produced by A. oryzae. The polar layer of the gochujang methanol (MeOH) extract more strongly inhibited the β-glucosidase activity of the crude enzyme extracted from gochujang than that of the nonpolar layer. The red pepper extract and high salt solution of the gochujang ingredients showed high β-glucosidase inhibition activity. These results indicate that flavonoid glycosides were not hydrolyzed by the β-glucosidase produced by A. oryzae during gochujang fermentation, which may have been due to the salt and hydrophilic compound(s) present in red pepper as main ingredients of gochujang.

Characterization of a Fibrinolytic Enzyme Secreted by Bacillus amyloliquefaciens CB1 and Its Gene Cloning

Bacillus amyloliquefaciens CB1 was isolated from cheonggukjang, a Korean fermented soy food. B. amyloliquefaciens CB1 secretes proteases with fibrinolytic activities. A gene homologous to aprE of Bacillus subtilis, aprECB1, was cloned from B. amyloliquefaciens CB1, and DNA sequencing showed that aprECB1 can encode a prepro-type serine protease consisting of 382 amino acids. When aprECB1 was introduced into B. subtilis WB600 using an E. coli-Bacillus shuttle vector, pHY300PLK, transformants showed fibrinolytic activity and produced a 28 kDa protein, the size expected for the mature enzyme. The 28 kDa fibrinolytic enzyme was purified from the culture supernatant of B. subtilis WB600 transformant. AprECB1 was completely inhibited by phenylmethylsulfonyl fluoride and almost completely inhibited by EDTA and EGTA, indicating that it is a serine metalloprotease. AprECB1 exhibited the highest specificity for N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide, a known substrate for α-chymotrypsin. Aα and Bβ chains of fibrinogen were quickly degraded by AprECB1, but the γ-chain was resistant.

소규모 국내생산 식물 발효식품의 바이오제닉아민 잔류특성

본 연구에서는 식물을 원료로 하여 제조된 발효식품들 중 지금까지 BAs에 대한 잔류분석연구가 진행되지 못하였던, 식품군들에 대해 BAs 잔류분석을 실시하였다. 조사대상 식품군으로는 식물 발효진액, 장아찌, 막걸리, 흑마늘, 발효차를 선정하였으며, 발효진액, 막걸리, 흑마늘, 발효차는 HIS, TYR, PUT, CAD, PHE 5종 BAs 의 총 함량이 1,000mg/kg을 초과하지 않았으나, 장아찌시료에서는 19.2-1,214 mg/kg으로 검출되었다. 이러한, 장아찌류의 고잔류 BAs는 간장과 된장 등 원료 장류에 의한 영향이 높을 것으로 사료되며, 장아찌에 대한 BAs 연구는 원료 및 제조 특성별 잔류 분석연구가 보완되어야 할 것이다. Ten major residual biogenic amines including toxic histamine and tyramine were investigated in the plant-based minor Korean fermented food. From the analyses of pickled vegetables, fermented vegetable extracts, fermented tea, black garlic and herbal rice wines, more than 100 mg/kg of histamine were found in pickled soy leaf and pickled mulberry leaf, and also over 1,000 mg/kg of total biogenic amines were found in pickled soy leaf. No sample was found over in black garlic, fermented tea, fermented vegetable extracts and herbal rice wine, less than 100 mg/kg of histamine and/or 1,000 mg/kg of total biogenic amines were observed. Interestingly, all the tested rice wines were found to be over 100 mg/kg of agmatine residue.

World Institute of Kimchi as a leading global institute of fermented foods

"Kimchi" is a world famous fermentated food originating from Korean cuisine. It has many health benefits and in order to systematically understand kimchi, the Korean government has set up the World Institute of Kimchi (WIKIM)--read more about kimchi and WIKIM in this forum article.