• Microbiology and Biotechnology Letters
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• v.24 no.2
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• pp.178-184
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• 1996

Dryfilm method by using 3M Petrifilm$^{TM}$ has been examined to replace conventional agar method for isolation of microorganisms from foods. The objectives of the present study were to evaluate suitability of dryfilm method as a microbial isolation method and to determine the effect of antimicrobial agent on dryfilm for isolation of microorganisms from foods. Five different foods, milk, ground beef, fishery surimi, Takju and wheat flour were used to isolate the natural microflora in foods and the inoculated Escheri chia coli. Standard method agar (SMA, Difco) and Petrifilm$^{TM}$ aerobic count (PAC, 3M) were used to isolate total microorganisms from foods. Violet red bile agar (VRBA), brilliant green lactose bile (BGLB) broth and Petrifilm$^{TM}$ coliform count (PCC, 3M) were used to isolate coliforms from foods. E. coli broth (EC broth) and Petrifilm$^{TM}$ E. coli count (PEC, 3M) were used to isolate E. coli from foods. Acidified potato dextrose agar (APDA) and Petrifilm$^{TM}$ yeast & mold count (PYMC, 3M) were used to isolate yeasts and molds from foods. Total aerobic plate counts isolated from five different foods by SMA and PAC (3M) were riot significantly different each other at P<0.05 level and were highly correlated each other ($\geq$0.96). Mugwort extract as an antimicrobial agent did not affect microbial enumeratiion of Dryfilm. Significantly higher number of coliform colonies were formed on VRBA than PCC (3M) from ground beef, but they were not significantly different in coliform colonies from milk samples. PCC (3M) and BGLB were not significantly different for enumeration of coliforms in milk and beef samples. Significantly higher number of E. coli were isolated by EC broth than PEC from ground beef, but these were not significontly different for enumeration of E. coli from milk. Yeast and mold counts isolated from Takju and wheat flour by APDA and PYMC (3M) were not significantly different at P<0.05 level. These data indicate that dryfilm method by using 3M Petrifilm$^{TM}$ can be successively used as an alternative to conventional agar method for enumeration of microorganisms in various foods.

• Journal of Microbiology
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• v.41 no.3
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• pp.262-265
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• 2003

Although enumerating bacterial cells is a fundamental step in understanding microbial ecosystems in marine environments, substantial decrease in bacterial counts with increasing sample storage time hampers the accurate estimation of bacterial biomass. We compared the variations in bacterial cell numbers caused by freezing and thawing of sample bottles or slides. Bacterial counts of seawater samples frozen only once in a sampling bottle yielded approximately 95％ of the original numbers after 90 days, whereas 80％ of the original count was obtained for samples prepared on slides. Only 67％ and 58％ of the original counts were recovered in samples repeatedly frozen and thawed in bottles or on slides, respectively. The results indicated that freezing a seawater sample in a bottle increased the consistency of the epifluorescence microscopic enumeration of bacterial cells.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.2
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• pp.283-294
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• 2007

Conventional culture-based methods of enumerating rumen microorganisms (bacteria, archaea, protozoa, and fungi) are being rapidly replaced by nucleic acid-based techniques which can be used to characterise complex microbial communities without incubation. The foundation of these techniques is 16S/18S rDNA sequence analysis which has provided a phylogenetically based classification scheme for enumeration and identification of microbial community members. While these analyses are very informative for determining the composition of the microbial community and monitoring changes in population size, they can only infer function based on these observations. The next step in functional analysis of the ecosystem is to measure how specific and, or, predominant members of the ecosystem are operating and interacting with other groups. It is also apparent that techniques which optimise the analysis of complex microbial communities rather than the detection of single organisms will need to address the issues of high throughput analysis using many primers/probes in a single sample. Nearly all the molecular ecological techniques are dependant upon the efficient extraction of high quality DNA/RNA representing the diversity of ruminal microbial communities. Recent reviews and technical manuals written on the subject of molecular microbial ecology of animals provide a broad perspective of the variety of techniques available and their potential application in the field of animal science which is beyond the scope of this treatise. This paper will focus on nucleic acid based molecular methods which have recently been developed for studying major functional groups (cellulolytic bacteria, protozoa, fungi and methanogens) of microorganisms that are important in nutritional studies, as well as, novel methods for studying microbial diversity and function from a genomics perspective.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.208-214
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• 2009

To avoid ambiguity in counting the number of colony, about 1,500 of colonies grown on B. cereus selective agar plates were grouped into 12 types by morphological difference and then identified by biochemical and 16S rDNA nucleotide sequence. Among them, seven colony types with 11 to 15 mm diameters of halo were identified as B. cereus or B. cereus subsp. cytotoxis. Five mm sized colonies with no halo, which have not been considered as B. cereus according to the manufacturer's manual, were identified as B. cereus. A colony type with double halos of only 6 mm in diameter was also B. cereus. Other three types were proven to be Enterococcus sp., Brevibacillus sp., and B. subtilis, respectively. PCR results showed that only 9 types that are identified as B. cereus strains harbor at least one of B. cereus toxin genes.

• Journal of Food Hygiene and Safety
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• v.23 no.3
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• pp.191-197
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• 2008

This work was intended for the identification of markers that are found only in the spoiled red pepper powder. When analyzed by GC/MASS, the spoiled red pepper powder contains characteristic naphthalene derivatives, 1, 2, 3, 5, 6, 7, 8, $8\alpha$-octahydro-1, $8\alpha$-dimethyl-7-(1-methylethenyl)-naphthalene and 2-isopropenyl-$4\alpha$, 8-dimethyl-1, 2, 3, 4, $4\alpha$, 5, 6, $8\alpha$-octahydronaphthalene, which have not found in the normal red pepper powder. In addition, microscopic observation and microbial enumeration of the red pepper powder had been performed. Images by scanning electron microscopy showed that the surfaces of spoiled pepper powder were rough with many kinds of microbes, compared with those of normal red pepper powder. A good correlation between the bacterial and fungal counts in the same sample was observed and could be clearly classified into two groups, the normal and the spoiled group, by difference in the microbial counts. These results suggest that the spoiled red pepper powder can be identified by a combination of GC/MASS, microbial counts, and scanning electron microscopy.

• Journal of Microbiology and Biotechnology
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• v.29 no.8
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• pp.1240-1247
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• 2019

This study was conducted to examine the inactivation effect of the combined treatment of high hydrostatic pressure (HHP; 400 MPa for 1, 3, and 5 min) and cationic surfactant washing (0.05% benzethonium chloride, BEC) against Listeria monocytogenes inoculated on fresh-cut broccoli (FCB). Washing with BEC at concentrations exceeding 0.05% resulted in 2.3 log-reduction of L. monocytogenes counts on FCB, whereas HHP treatment had approximately 5.5-5.6 log-reductions regardless of the treatment time. Scanning electron microscopy corroborated microbial enumeration, revealing that the combined treatment was more effective in removing L. monocytogenes from FCB than individual treatment with HHP or BEC. Color and total glucosinolate content were maintained after the combined treatment, although the hardness of the FCB slightly decreased. The results clearly suggest that the combined treatment of HHP and BEC washing has potential value as a new sanitization method to improve the microbial safety of FCB.

• Environmental Engineering Research
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• v.21 no.2
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• pp.211-218
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• 2016

Cheonggye-cheon is a partly restored urban stream located in central Seoul. We monitored fecal contamination using three different fecal indicators, total coliforms (TC), fecal coliforms (FC) and E. coli, to assess differences in each indicator on days of varying weather conditions. Presumptive TC, FC and E. coli colonies were identified by their 16S rRNA sequences. The results showed that enumeration of E. coli provided a better reflection of fecal contamination of the stream than TC and FC. The main sources of contamination were the inflow of fecal-polluted groundwater from the vicinity of a subway line and two inflowing streams. The fecal contamination was worsened on days with heavy rain because untreated sewage from a collecting facility flowed into the stream. Moreover, growth potential of fecal indicator (E. coli) in situ induced by algal exudates was measured. Our results suggest that an appropriate standard based on E. coli rather than TC and FC should be established for improving water quality management strategies of Cheonggye-cheon in the future.

• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.232-236
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• 2006

Effect of Bifidobacterium longum BO-11 isolated from healthy adult feces on Baechu-kimchi made of chinese cabbage was evaluated. Upon enumeration of bifidobacteria using BS medium, microorganisms grew slowly in kimchi during fermentation at $4^{\circ}C$. Taste preference of bifidobacteria-added kimchi was higher than that of conventional kimchi without bifidobacteria.

• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.2
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• pp.135-140
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• 1988

A laboratory experiment was conducted to find out the number of soil microorganisms, identification and enumeration of soil microbial species on the mineral and volcanic ash soil with different cropping system of the Jeju Island. The results obtained were summarized as follows: 1. The number of bacteria was high in mineral soil with rotation of upland crops than that of volcanic ash soil with continuous cropping system. 2. According to identification of soil bacteria, the most of bacteria were composed to short rod with Gram negative. Among the bacteria species, Rhizobium spp. and Flavobacterium spp. were most high population in both of mineral and volcanic ash soil. 3. The number of fungi in mineral soils were reduced by the rotated cultivation of upland crops but no significant differences were observed in volcanic ash soil with continuous cropping system. On the other hand, Aspergillus spp., Fusarium spp., and Penicillium spp. were most high population in both of mineral and volcanic ash soil. 4. Comparing of the number and species ot microorganism to the cash crops soil in main land, about 10 to 100 times for bacteria and more than two times for the number and species of fungi were lowered in Jeju Island soil.