• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.7
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• pp.1025-1031
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• 2011

The objective of this study was to compare the performances of conventional microbiological media used in isolation of Shigella spp. from foods. Total of six selective media, including MacConkey agar (MAC), Salmonella Shigella agar (SSA), desoxycholate citrate agar (DCA), xylose lysine desoxycholate agar (XLD), hektoen enteric agar (HEA), and CHROMagar, were tested. MAC showed almost the same colony numbers as compared to tryptic soy agar (TSA) while DCA showed significantly lower colony numbers when cultivated Shigella spp. was counted in each medium. In a food recovery test with beef, pork and shrimp, S. sonnei recovered well on CHROMagar (p<0.05). With lettuce and cabbage, S. sonnei displayed significantly significant recovery (p<0.05) on SSA in comparison with other selective media. Heat-injured cells recovered well on MAC and SSA. In a specificity test using Enterobacteriaceae strains, HEA was identified as having the highest specificity among the tested media. However, Morganella spp. could not be differentiated from Shigella spp. on any of the tested selective media. Shigella spp. precluded the possibility of isolation from foods by a single 'best' selective medium. Consequently, a combination of complementary selective media or selection of appropriate media according to cell conditions must be considered for comprehensive isolation.

• Journal of Life Science
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• v.25 no.9
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• pp.1036-1042
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• 2015

By using effective sanitizers, early block for transmission of pathogens is the effective way to prevent epidermic outbreaks. Here we developed a chlorine oxide bubbling type of sanitizing tablets and evaluated the disinfectant and sanitization effects. The sanitizers showed 99.999% of sanitization effect for Escherichia coli ATCC 10536 and Staphylococcus aureus ATCC 6538 strains for 5 min±10 sec on 20±1℃ in clean condition by dilution-neutralization method. It reduced more than 5 log₁₀ cfu/ml of a legal permission standard of colony reduction. When a few used socks and underwear soaked for one hour in the 0.1% of the sanitizing tablets, no microorganisms were grown on CHROMagar plates. However, on CHROMagar plates of the no sanitizing tablets treated control, about 6.5×10⁴ cfu/ml of Staphylococcus sp., Klebsiella sp. and Enterococus sp. were grown. Furthermore, the sanitizing tablets killed approximately 1.5x10⁸ cfu/ml of E. coli BL21 in 5 minutes. Therefore, we concluded that the chlorine based bubbling type of sanitizing tablets satisfied the legal standard for the regulation of food and drug safety for disinfectants and sanitizers to pathogens and daily supplies.

• Microbiology and Biotechnology Letters
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• v.50 no.4
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• pp.488-500
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• 2022

Most fungal infections by opportunistic yeast pathogens such as Candida spp. are the major causes of morbidity and mortality in patients with lowered immune. Previous studies have reported that some strains of Candida secret secondary metabolites play an important role in the decreasing of immunity in the infected patient. In this study, 110 Candida spp. were isolated from different clinical specimens from Baghdad hospitals. Candida isolates were identified by conventional methods, they were processed for Candida speciation on CHROMagar. The results of identification were confirmed by internal transcribed spacer (ITS) sequencing. Phylogenetic trees were analyzed with reference strains deposited in GenBank. Antifungal susceptibility testing was evaluated by the disc diffusion method and performed as recommended by the Clinical and Laboratory Standard Institute (CLSI) M44-A document. Candida isolates investigated produce secondary metabolites gliotoxin with HPLC technique and quantification. Out of 110 Candida isolates, C. albicans (66.36%) was the most frequent isolate, followed by the isolates of C. tropicalis (10.9%) and C. glabrata (6.36%) respectively. Concerning the antifungal susceptibility test, Candida isolates showed a high level of susceptibility to Miconazole (70.9%), Itraconazole (68.2%), and Nystatine (64.5%). The ability of obtained isolates of Candida spp. to produce gliotoxin on RPMI medium was investigated, only 28 isolates had the ability to secret this toxin in culture filtrates. The highest concentrations were detected in C. albicans (1.048 ㎍/ml). Gliotoxin productivity of other Candida species was significantly lower. The retention time for gliotoxin was approximately 5.08 min.

• Korean Journal of Food Science and Technology
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• v.48 no.4
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• pp.323-328
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• 2016

In this study, specific and rapid enrichment and growth conditions for the most important, classic non-O157 enterohemorrhagic Escherichia coli (EHEC) serogroups were assessed. Three enrichment broth types, namely, EC medium with MUG broth, BRILA broth, and mTSB broth with novobiocin, were compared to identify the optimum enrichment broth for EHEC isolation. Four kinds of selective media, namely, ENDO agar, Chromocult agar, TBX agar, and CHROMagar$^{TM}$ STEC medium, were compared to identify the optimum one for non-O157 EHEC isolation. The results suggested that incubation in EC medium with MUG broth at $42^{\circ}C$ for 20 h is optimum for the enrichment of non-O157 EHEC. TBX agar was identified to have the highest specificity among the tested media. Consequently, a combination of complementary selective media according to serotype must be considered for comprehensive isolation of specific EHEC.

• Korean Journal of Microbiology
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• v.48 no.1
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• pp.22-28
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• 2012

Vibrio parahaemolyticus is one of the major agents responsible for food poisoning during summer in Korea, which is transmitted via seawater or seafoods. Recently, distribution of the bacteria in the marine environment has been increased due to global warming. Great concern also has been raised regarding public hygiene as well as marine culture by the emergence of pathogens with antibiotic resistance. Therefore, distribution of V. parahaemolyticus and antibiotic resistance of the isolates were monitored in 7 coastal areas of Kyonggi Province and Incheon by sampling seawater, fishes and clams monthly. V. parahaemolyticus was detected from 47.7% of 966 samples (seawater 61.9%, seafoods 41.8%) analyzed using $CHROMagar^{TM}$ and TCBS agar plates as well as multiplex PCR. Among 13 antibiotics tested, resistance to vancomycin and ampicillin was observed in 97.3% and 87.3% of the isolates, respectively, and the ratios of them resistant to cephalothin (48.8%) and rifampin (46.1%) were also high. The isolates were most highly sensitive to chloramphenicol (91.7%) and trimethoprim-sulfamethoxazole (91.8%). The ratio of sensitivity for other antibiotics was also high in the descending order of gentamycin (82.3%), tobramycin (74.8%), nalidixic acid (71.6%), tetracyclin (69.4%), cefotaxime (63.0%). About 69% of the isolates showed multiple drug resistance toward 3 antibiotics including vancomycin and ampicillin. Two of them exhibited resistance for 11 antibiotics used in this study. Plasmid profile analysis of the isolates with antibiotic resistance revealed that 55.1% of them retained plasmids of 24 different types. However, no clear inter-relationship between the resistance and the plasmid profile has been observed.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.569-573
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• 2010

A quantitative detection method for Salmonella in seafood was developed using a SYBR Green-based real-time PCR assay. The assay was developed using pure Salmonella DNA at different dilution levels [i.e., 1,000 to 2 genome equivalents (GE)]. The sensitivity of the real-time assay for Salmonella in seeded seafood samples was determined, and the minimum detection level was 20 CFU/g, whereas a detection level of 2 CFU/ml was obtained for pure culture in water with an efficiency of ${\geq}85%$. The real-time assay was evaluated in repeated experiments with seeded seafood samples and the regression coefficient ($R^2$) values were calculated. The performance of the real-time assay was further assessed with naturally contaminated seafood samples, where 4 out of 9 seafood samples tested positive for Salmonella and harbored cells <100 GE/g, which were not detected by direct plating on Salmonella Chromagar media. Thus, the method developed here will be useful for the rapid quantification of Salmonella in seafood, as the assay can be completed within 2-3 h. In addition, with the ability to detect a low number of Salmonella cells in seafood, this proposed method can be used to generate quantitative data on Salmonella in seafood, facilitating the implementation of control measures for Salmonella contamination in seafood at harvest and post-harvest levels.

• Journal of Microbiology and Biotechnology
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• v.21 no.9
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• pp.954-959
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• 2011

There have been a number of studies conducted in order to compare the efficiencies of recovery rates, utilizing different protocols, for the isolation of L. monocytogenes. However, the severity of multiple cell injury has not been included in these studies. In the current study, L. monocytogenes ATCC 19112 was injured by exposure to extreme temperatures ($60^{\circ}C$ and $-20^{\circ}C$) for a one-step injury, and for a two-step injury the cells were transferred directly from a heat treatment to frozen state to induce a severe cell injury (up to 100% injury). The injured cells were then subjected to the US Food and Drug Administration (FDA), the ISO-11290, and the modified United States Department of Agriculture (mUSDA) protocols, and plated on TSAyeast (0.6% yeast), PALCAM agar, and CHROMAgar Listeria for 24 h or 48 h. The evaluation of the total recovery of injured cells was also calculated based on the costs involved in the preparation of media for each protocol. Results indicate that the mUSDA method is best able to aid the recovery of heat-injured, freeze-injured, and heat-freeze-injured cells and was shown to be the most cost effective for heat-freeze-injured cells.

• Journal of Food Hygiene and Safety
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• v.27 no.2
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• pp.169-175
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• 2012

Five kinds of selective media, such as mannitol salt agar (MSA), Baird-Parker agar (BPA), Baird-Parker supplemented with rabbit plasma fibrinogen (BPA+RPF), CHROMagar Staphylococcus aureus (CSA), and Petrifilm Staph Express count system (Petrifilm), were compared to recommend the optimum selective media for isolation of Staphylococcus aureus from agricultural products. Seventy four target and non target bacteria were inoculated on five selective media to analyze sensitivity and specificity. In the recovery test of injured S. aureus cells, S. aureus was exposed to acid (1% lactic acid for 10 min), heat ($60^{\circ}C$ for 90s), and cold ($-20^{\circ}C$ for 1h) conditions. And artificially contaminated agricultural products (iceberg lettuce, green pepper, and cherry tomato) was enumerated on five selective media. The sensitivity of BPA+RPF, CSA, Petrifilm, MSA, and BPA were 100%, 100%, 100%, 90.5%, 90.5%, respectively. In addition, the specificity of BPA+RPF, CSA, MSA, BPA and Petrifilm were 100%, 100%, 84.6%, 75.0%, 67.3%, respectively. However, no difference among five selective media was observed in recovery on injured S. aureus cell and enumeration from agricultural products. This results suggest that BPA+RPF and CSA are the optimum media for detection of S. aureus from agricultural products.