• Microbiology and Biotechnology Letters
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• v.22 no.2
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• pp.210-216
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• 1994

Phage utilizing medium and BL agar supplemented with antibiotic Tc(tetracycline) were developed as selective media for the isolation and counting of bifidobacteria in dairy products. The former was based on the host specificity of phage. When bifidobacteria and Lactobacillus casei HY 2782 were mixed together in dairy product, L. casei HY 2782 was laysed by J1 phage which has host specificity to L. casei HY 2782 whereas bifidobacteria grew well on the selective medium added wIth J1 phage. The latter was found to inhibit the growth of S. salivarius subsp. thermophilus, L. acidophilus, and L. casei, but commercial bifidobacteria grew well in Tc-containing BL agar.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.25-31
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• 2016

An enterococci selective medium was developed to detect the presence of enterococci for use as a fecal contamination indicator. Among several media which have been known to detect enterococci, the following 9 different kinds of media were selected: Enterococci Confirmatory agar, Azide dextrose agar, Bromocresol-purple azide agar, Esculin bile agar, Citrate azide tween carbonate agar, KF Streptococcus agar, BROLACIN agar, Kanamycin esculin azide agar, and Membrane filter Enterococcus selective agar. Various components from the nine media were mixed to develop a more effective enterococcus selective medium. The newly developed medium named as 'Enterococcus Mixed medium' was more effective than the previous 9 media. Enterococci strains (Enterococcus avium KACC 10788, Enterococcus faecium KACC 11954, Enterococcus saccharolyticus KACC 10783, Enterococcus durans KACC 10787, Enterococcus faecalis KACC 11304, and Enterococcus hirae KACC 10779) and non-enterococci strains (Escherichia coli KACC 10005, Staphylococcus aureus subsp. aureus KACC 10768, and Bacillus subtilis KACC 10111) were used to test the new medium. As a result, the enterococci strains grew well on the Enterococcus Mixed medium whereas the non-enterococci strains did not grow well on it. Additionally, growth of enterococci with freshwater and seawater samples was observed to be good on the Enterococcus Mixed medium. The result of this study confirmed that the Enterococcus Mixed medium was effective in detecting the target enterococci.

• KSBB Journal
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• v.11 no.6
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• pp.726-732
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• 1996

Selective adsorption of plant metabolites from a polar dilute solution onto a polycarboxyl ester sorbent (XAD-7) was investigated. Experimental results demonstrated that neutral resins could selectively concentrate specific flavonoids from dilute aqueous mixtures. Adsorption was dependent on the pH of medium, dosage of the resins and medium composition. Especially the medium composition was a key factor for the selective adsorption and it was found that the selective adsorption was dependent on specific sorbent-sorbate-medium characteristics. Under the optimum condition, selectivity increased up to 85% and the yield of recovery was approached to 98%. It was also found that XAD-7 adsorbed flavonoids in the order of hydrophobicity.

• The Plant Pathology Journal
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• v.29 no.4
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• pp.446-450
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• 2013

The ascomycete fungus Fusarium graminearum is a major causal agent for Fusarium head blight in cereals and produces mycotoxins such as trichothecenes and zearalenone. Isolation of the fungal strains from air or cereals can be hampered by various other airborne fungal pathogens and saprophytic fungi. In this study, we developed a selective medium specific to F. graminearum using toxoflavin produced by the bacterial pathogen Burkholderia glumae. F. graminearum was resistant to toxoflavin, while other fungi were sensitive to this toxin. Supplementing toxoflavin into medium enhanced the isolation of F. graminearum from rice grains by suppressing the growth of saprophytic fungal species. In addition, a medium with or without toxoflavin exposed to wheat fields for 1 h had 84% or 25%, respectively, of colonies identified as F. graminearum. This selection medium provides an efficient tool for isolating F. graminearum, and can be adopted by research groups working on genetics and disease forecasting.

• Food Science of Animal Resources
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• v.30 no.1
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• pp.154-162
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• 2010

This study was carried out to compare the efficacy and selectivity of TOS and BS media for enumeration of bifidobacteria in commercial fermented milk products. First, bifidobacteria was isolated from 20 fermented milk products, and all isolated bifidobacteria were identified by genomic technology as Bifidobacterium lactis. The two media significantly differed from each other with regard to the recovery of B. lactis, that is, the recovery of this organism was as much as 6 logs lower on BS medium than on TOS. When the concentration of BS solution (mixture of paromomycin sulfate, neomycin, sodium propionate, and lithium chloride) used in BS medium was reduced to 50% (BS50), a relatively high percentage recovery of bifidobacteria from pure cultures was achieved. Susceptibility tests to antibiotics and tests for selective agents for the isolated bifidobacteria and lactic acid bacteria were conducted. The BS solution inhibited some lactic acid bacteria and Bifidobacterium species, while mupirocin (MU) suppressed the growth of all tested lactic acid bacteria but not Bifidobacterium. As compared with BS50 medium, TOS with or without MU showed good bifidobacteria recovery and readily distinguishable colonies; in particular, TOS supplemented with MU had a high selectivity for bifidobacteria. In conclusion, all results suggested that TOS medium with or without MU was found to be suitable for selective enumeration of bifidobacteria from mixed cultures in fermented milk, and better in that capacity than BS medium.

• Journal of Dairy Science and Biotechnology
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• v.39 no.1
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• pp.9-19
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• 2021

Enterobacter sakazakii (Cronobacter spp.) causes meningitis, necrotizing enterocolitis, sepsis, and bacteremia in neonates and children and has a high mortality rate. For rapid E. sakazakii detection, various differential and selective media containing α-glucosidase substrates, such as 5-bromo-4-chloro-3-indolyl-α-D-glucopyranoside (BCIG) or 4-methylumbelliferyl-α-D-glucoside (α-MUG), have been developed as only E. sakazakii exhibits α-glucosidase activity in the genus Enterobacter. However, Escherichia vulneris (family: Enterobacteriaceae) can also utilize α-glucosidase substrates, thereby resulting in false positives. Various iron sources are known to promote the growth of gram-negative bacteria. This study aimed to develop a selective medium containing α-glucosidase substrates for E. sakazakii detection that would eliminate false positives, such as those of E. vulneris, and to determine the role of iron source in the medium. Three previously developed (TPD) media, i.e., Oxoid, OK, and VRBG, and the medium developed in this study, i.e., NGTE, were evaluated using 58 E. sakazakii and 5 non-E. sakazakii strains. Fifty-four E. sakazakii strains appeared as fluorescent or chromogenic colonies on all four media that were assessed. Two strains showed colonies on NGTE medium and not on TPD media. In contrast, the remaining two strains showed colonies on TPD media and not on NGTE medium. None of the non-E. sakazakii strains showed fluorescent or chromogenic colonies on any of the evaluated media except E. vulneris, which showed colonies on TPD media and not on NGTE medium. This study demonstrated that the newly developed NGTE medium was not only equally efficient in promoting the growth of bacterial colonies when compared with the currently available media but also eliminated false positives, such as E. vulneris.

• The Plant Pathology Journal
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• v.40 no.2
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• pp.106-114
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• 2024

Fusarium head blight (FHB), predominantly caused by Fusarium graminearum and F. asiaticum, is a significant fungal disease impacting small-grain cereals. The absence of highly resistant cultivars underscores the need for vigilant FHB surveillance to mitigate its detrimental effects. In 2023, a notable FHB outbreak occurred in the southern region of Korea. We assessed FHB disease severity by quantifying infected spikelets and grains. Isolating fungal pathogens from infected samples often encounters interference from various microorganisms. We developed a cost-effective, selective medium, named BGT (Burkholderia glumae Toxoflavin) medium, utilizing B. glumae, which is primarily known for causing bacterial panicle blight in rice. This medium exhibited selective growth properties, predominantly supporting Fusarium spp., while substantially inhibiting the growth of other fungi. Using the BGT medium, we isolated F. graminearum and F. asiaticum from infected wheat and barley samples across Korea. To further streamline the process, we used a direct PCR approach to amplify the translation elongation factor 1-α (TEF-1α) region without a separate genomic DNA extraction step. Phylogenetic analysis of the TEF-1α region revealed that the majority of the isolates were identified as F. asiaticum. Our results demonstrate that BGT medium is an effective tool for FHB diagnosis and Fusarium strain isolation.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.279-284
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• 1996

To develop a selective medium for the isolation and the detection of leuconostocs from the various samples including fermented vegetables, ten strains of leuconostocs and seven strains of lactobacilli were tested for their sensitivity to various antibiotics. The basal-medium containing 5 ${\mu}g/ml$ of novobiocin inhibited the growth of lactobacilli completely, but not that of leuconostocs. On the basis of this result, a new selective medium was developed and to be named NLS medium. This medium contains 1% Tryptone (Difco), 0.1% Yeast Extract (Difco), 2% sucrose, 0.1% Beef Extract (BBL), 0.5% sodium acetate, 0.2% ammonium sulfate, 0.01% magnesium sulfate, 0.2% dipotassium phosphate, 0.05% sorbic acid, 75 ppm sodium azide (Sigma), 0.1% (vol/vol) Tween 80, 30 ${\mu}g/ml$ of Vancomycin (Sigma), 5${\mu}g/ml$ of Novobiocin (Sigma), 0.5${\mu}g/ml$ of cysteine HCI, and 1.5% Agar (Difco). All of the eighty six isolates obtained from some foodstuffs were identified as members of the genus Leuconostoc. Comparative counts with the MRS, PES, LUSM, and NLS medium indicated that the recovery percent was lower than other selective media. Therefore, this result suggested that NLS medium was suitable for the isolation of leuconostocs, but not for counting or enumerating.

• Journal of Food Hygiene and Safety
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• v.31 no.3
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• pp.222-225
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• 2016

In this study, the performance of five selective media for coliform bacteria was evaluated. In total, 83 coliform isolates from ready-to-eat food and 21 reference strains were inoculated in five agar media : Chromocult coliform agar (Merck Millipore), HiCrome coliform agar (Sigma), CHROMagar ECC chromogenic media, Brilliance E. coli/coliform selective agar (OXOID), and endo agar (Merck Millipore). Coliform isolates and reference strains were inoculated on the selective media to test media sensitivity and specificity. The tested media showed the following sensitivities for the isolated strains: Chromocult coliforms agar and HiCrome coliform agar, 94%; Brilliance E. coli/coliform selective agar, 93%; CHROMagar ECC chromogenic media, 92%; and endo agar, 74%. In addition, all media showed 100% specificity, except for endo agar (71%). Moreover Chromocult coliform agar and HICrome coliform agar showed high levels recovery. Taken together, these results identified Chromocult coliform agar and HICrome coliform agar as an effective selective medium for coliforms with higher sensitivity and specificity compared to other media tested in this study.

• Microbiology and Biotechnology Letters
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• v.23 no.2
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• pp.214-219
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• 1995

In fermentation of dairy products, bifidobacteria is used in conjunction with other lactic acid bacteria, such as L. acidophilus, L. bulgaricus and S. thermophilus, rendering the enumeration of bifidobacteria difficult. In order to develop optimum conditions for selective enumeration of bifidobacteria, we examined MIC of several antibiotics against various bifidobacteria and other lactic acid bacteria. The growth of L. acidophilus, L. bulgaricus and S. thermophilus were inhibited by lithium chloride at the concentration of less than 4 mg/ml, whereas growth inhibition of bifidobacteria occurred at concentrations over 6-10 mg/ml. Tetracycline and chloramphenicol were also found to selectively inhibit growth of other lactic acid bacteria at the concentration of 1-3 $\mu$g/ml. Addition of 6 mg/ml lithium chloride, 1 $\mu$g/ml, tetracycline or 3 $\mu$g/ml chloramphenicol to medium was found to be optimal for selective enumeration of bifidobacteria. By using these three inhibitory chemicals in the TPY medium, higher number of bifidobacteria were selectively isolated than with NPNL agar and LP agar.