• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.8
• /
• pp.1258-1264
• /
• 2005

We determined the effect of chlorine dioxide ($ClO_{2}$) treatment on microbial growth and quality of saury. Saury samples were treated with aqueous $ClO_{2}$ at 3, 10, and 50 ppm. After the treatment, saury samples were stored at -20$^{\circ}C$ and 4$ ^{\circ}C$, respectively. Saury samples treated with $ClO_{2}$ had significantly lower total bacterial counts during storage. In particular, treatment of 50 rpm $ClO_{2}$ decreased total bacterial count most significantly among the $ClO_{2}$ treated saury samples. After 4 days, populations of total bacteria for the control reached 6.43 log CFU/g, while the sample treated with 50 ppm of $ClO_{2}$ had 5.47 log CFU/g at the 9th day of storage. $ClO_{2}$ treatment also delayed increase in the population of psychrotrophic bacteria on saury. The pH of saury samples decreased with increase of $ClO_{2}$ concentration. Volatile basic nitrogen (VBN) and thiobarbituric acid reactive substance (TBARS ) values of saury samples increased during storage, regardless of $ClO_{2}$ concentration. Sen-sory evaluation of saury samples showed that treatment with $ClO_{2}$ could improve the quality of saury. These results indicate that $ClO_{2}$ treatment could be useful in improving microbial safety and quality of saury.

• Asian-Australasian Journal of Animal Sciences
• /
• v.25 no.9
• /
• pp.1248-1254
• /
• 2012

The effect of silage additives on ensiling characteristics and nutritive value of Napier grass (Pennisetum purpureum) silages was studied. Napier grass silages were made with no additive, fermented juice of epiphytic lactic acid bacteria (FJLB), molasses or cassava meal. The ensiling characteristics were determined by ensiling Napier grass silages in airtight plastic pouches for 2, 4, 7, 14, 21 and 45 d. The effect of Napier grass silages treated with these additives on voluntary feed intake, digestibility, rumen fermentation and microbial rumen fermentation was determined in 4 fistulated cows using $4{\times}4$ Latin square design. The pH value of the treated silages rapidly decreased, and reached to the lowest value within 7 d of the start of fermentation, as compared to the control. Lactic acid content of silages treated with FJLB was stable at 14 d of fermentation and constant until 45 d of ensiling. At 45 d of ensiling, neutral detergent fiber (NDF) and acid detergent fiber (ADF) of silage treated with cassava meal were significantly lower (p<0.05) than the others. In the feeding trial, the intake of silage increased (p<0.05) in the cow fed with the treated silage. Among the treatments, dry matter intake was the lowest in the silage treated with cassava meal. The organic matter, crude protein and NDF digestibility of the silage treated with molasses was higher than the silage without additive and the silage treated with FJLB. The rumen parameters: ruminal pH, ammonia-nitrogen ($NH_3$-N), volatile fatty acid (VFA), blood urea nitrogen (BUN) and bacterial populations were not significantly different among the treatments. In conclusion, these studies confirmed that the applying of molasses improved fermentative quality, feed intake and digestibility of Napier grass.

• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.4
• /
• pp.480-485
• /
• 2004

Fatty acid methyl ester (FAME) technology was evaluated as a monitoring tool for quantification of Nocardia amarae causing a nuisance foaming problem in activated sludge process. The identified signature peak was 19:1 alcohol as a reliable unique peak to N. amarae. Chemostat study revealed that the distribution and quantity of fatty acid peaks were dependent on the growth stage of Nocardia. The FAME results were similar for two relatively high dilution rates; however, the amounts of signature peaks extracted from the 4 and 6 day cultures were significantly higher. This dependence of signature peaks on the physiological state of the organism may be a useful information to assess the health of microbial populations in activated sludge. A laboratory scale batch foaming potential experiment provided a critical foaming level depending on Nocardia population. This critical Nocardia level determined in this study was in terms of either the threshold filament intersections number or the threshold signature FAME amount. The threshold peak area of signature FAME (19:1 alcohol) and corresponding filament counts were 430PA/mg VSS and $1.45{\times}10^6$ intersections/g VSS, respectively. The threshold signature FAME level could be effectively applied as a criterion for diagnosing foam occurrence in activated sludge system.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.10
• /
• pp.1808-1819
• /
• 2017

Knowledge on the functional characteristics and temporal variation of anaerobic bacterial populations is important for better understanding of the microbial process of two-stage anaerobic reactors. However, owing to the high diversity of anaerobic bacteria, close attention should be prioritized to the frequently abundant bacteria that were defined as core bacteria and putatively functionally important. In this study, using MiSeq sequencing technology, the core bacterial community of 98 operational taxonomic units (OTUs) was determined in a two-stage upflow blanket filter reactor treating pharmaceutical wastewater. The core bacterial community accounted for 61.66% of the total sequences and accurately predicted the sample location in the principal coordinates analysis scatter plot as the total bacterial OTUs did. The core bacterial community in the first-stage (FS) and second-stage (SS) reactors were generally distinct, in that the FS core bacterial community was indicated to be more related to a higher-level fermentation process, and the SS core bacterial community contained more microbes in syntrophic cooperation with methanogens. Moreover, the different responses of the FS and SS core bacterial communities to the temperature shock and influent disturbance caused by solid contamination were fully investigated. Co-occurring analysis at the Order level implied that Bacteroidales, Selenomonadales, Anaerolineales, Syneristales, and Thermotogales might play key roles in anaerobic digestion due to their high abundance and tight correlation with other microbes. These findings advance our knowledge about the core bacterial community and its temporal variability for future comparative research and improvement of the two-stage anaerobic system operation.

• Food Science of Animal Resources
• /
• v.35 no.4
• /
• pp.564-571
• /
• 2015

Grape seeds and pericarp are rich in procyanidins, a class of natural antioxidants and antimicrobials that can provide phytonutrients for healthy eating and extend food shelf life. The objective of this study was to assess the effect of procyanidins as preservatives in pork meat patties for 14 d. Pork patties were treated with 0, 0.1, or 0.3% procyanidin, and meat color, pH, volatile basic nitrogen (VBN), 2-thiobarbituric acid reactive substance (TBARS) values, and microbial populations were determined during storage at 4℃ for 14 d. The color of pork patties treated with procyanidin showed lower lightness and higher redness values than untreated controls, and procyanidin treatment reduced pH values significantly (p<0.05). VBN values decreased significantly (p<0.05) with the 0.3% procyanidin treatment and increased significantly (p<0.05) during storage. TBARS values were markedly lower in procyanidin-treated meat than in the untreated control. In addition, procyanidin suppressed total bacterial colony and Escherichia coli counts significantly (p<0.05) relative to the control samples. Our findings suggest that procyanidin could be used as a food preservative in pork patties due to its natural antioxidation and antimicrobial activities, and that it may contribute to an improved healthy diet.

• Journal of Wetlands Research
• /
• v.14 no.3
• /
• pp.419-428
• /
• 2012

Taxonomic identification of phytoplankton has been a difficult task, even for the experienced taxonomist. Many non-descript, yet abundant, phytoplanktons do exist without distinguishing features which cause difficulties in morphological identification. Using PCR(polymerase chain reaction)-DGGE(denaturing gradient gel electrophoresis)method, which is known to be a powerfulfingerprinting technique to analyze diversity and dynamics of microbial populations, this study aimed to find the way to overcome the limitation of morphological identification. As a result, a total of 46 bands from samples in five lakes were detected in September and 27 bands in November. Fingerprinting results showed convenient and comparative analyses among each sampling site. In this study, PCR-DGGE method was used to figure out diversity and dynamics of plankton community in the lakes of North-Han River system. Also, the possibility of DGGE technique as an identification tool for phytoplankton was estimated.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.5
• /
• pp.831-838
• /
• 2018

Trophic interactions of introduced biocontrol fungi with soil animals can be a key determinant in the fungal proliferation and activity. This study investigated the trophic interaction of an introduced biocontrol fungus with soil nematodes. The biocontrol fungus Trichoderma harzianum ThzID1-M3 and the fungivorous nematode Aphelenchoides sp. (10 per gram of soil) were added to nonsterile soil, and microbial populations were monitored for 40 days. Similar results were obtained when the experiment was duplicated. ThzID1-M3 stimulated the population growth of indigenous nematodes (p < 0.05), regardless of whether Aphelenchoides sp. was added. Without ThzID1-M3, indigenous nematodes did not increase in number and the added Aphelenchoides sp. nematodes almost disappeared by day 10. With ThzID1-M3, population growth of nematodes was rapid between 5 and 10 days after treatment. ThzID1-M3 biomass peaked on day 5, dropped at day 10, and then almost disappeared at day 20, which was not influenced by the addition of nematodes. In contrast, a large quantity of ThzID1-M3 hyphae were present in a heat-treated soil in which nematodes were eliminated. Total fungal biomass in all treatments peaked on day 5 and subsequently decreased. Addition of nematodes increased the total fungal biomass (p < 0.05), but ThzID1-M3 addition did not affect the fungal biomass. Hyphae of total fungi when homogenously distributed did not support the nematode population growth; however, hyphae of the introduced fungus did when densely localized. The results suggest that soil fungivorous nematodes are an important constraint on the hyphal proliferation of fungal agents introduced into natural soils.

• Asian-Australasian Journal of Animal Sciences
• /
• v.12 no.3
• /
• pp.417-421
• /
• 1999

This experiment examined the effects of feeding Aspergillus oryzae (AO) culture to laying hens, on fecal microbial populations, fecal pH and moisture content, egg quality, and metabolizabilities of several nutrients. Sixteen commercial 38-wk-old laying hens were randomly allotted to four diets: control; with 0.15% locally produced AO culture; with 0.3% locally produced AO culture, and; or with 0.3% imported AO. Each treatment consisted of four replicates (cages) containing one bird per cage according to a completely randomized design. After 4 wk, AO were recovered in the feces of birds fed the AO diets, indicating that AO might pass through the fore-gut alive and become active in the hind gut. The number of Lactobacillus spp. in feces was higher in all treated groups than that of the control, indicating that AO would provide a beneficial environment for the Lactobacillus spp. to proliferate in the intestine. The number of fecal E. coli was significantly reduced by the addition of AO. A similar trend was also found for aerobic bacteria. Although not significant, fecal moisture contents tended to be reduced by the addition of AO. Fecal pH was not significantly different among the treatments. The addition of AO did not affect the various economic traits of eggs. Metabolizabilities of gross energy and dry matter measured during the 5th wk were increased by the AO supplementation. It appears that AO culture alone could be used as a probiotic supplement for layers.

• Asian-Australasian Journal of Animal Sciences
• /
• v.33 no.3
• /
• pp.373-381
• /
• 2020

There is a need for newer feed additives due to legal prohibition on inclusion of growth promoting antibiotics in livestock diets in several countries due to antimicrobial resistance. In this context, rare earth elements (REE) have gained attention among animal nutritionists as potential growth promoters. Currently, several studies have reported better weight gain, milk production, egg laying capacity and feed conversion efficiency among different breeds of farm animals following supplementation with REE, with however largely inconsistent results. Furthermore, REE supplementation has also shown to improve ruminal fibrolytic and proteolytic activities as well as flavor of meat with negligible residues in edible tissue, however the mechanism behind this action is still unclear. According to existing research, due to their poor absorption and similarity with calcium REE might exert their action locally on gut microbial populations within the gastrointestinal tract (GIT). Moreover, REE have also shown anti-inflammatory, anti-oxidative as well as immune stimulating effects. The present review aims to broaden the knowledge about use of REE as feed additives for livestock and sum up efficacy of REE supplementation on performance and health of animals by comparing the findings. Till date, researches with REE have shown properties that make them a promising, new and safe alternative feed additive but further exploration is recommended to optimize effects and clarify discrepancy of various results before practical proposals can be drafted.

• Journal of Microbiology and Biotechnology
• /
• v.12 no.1
• /
• pp.166-171
• /
• 2002

The genus Leuconostoc is generally recognized as a favorable microorganism associated with a good taste of Kimchi and Lactobacillus plantarum is responsible for the overripening and acidification of Kimchi. A rapid and reliable PCR-based method to monitor the change of these lactic acid bacterial populations during Kimchi fermentation was attempted. A Leuconostoc-specific primer set was chosen from the conserved sequences of 16S rRNA genes among Leuconostoc species. The Lb. plantarum-specific primer set was the internal segments of a Lb. plantarum-specific probe which was isolated after randomly amplified polymorphic DNA (RAPD) analysis and tested for identification. The specificity of this protocol was examined in DNA samples isolated from a single strain. In agarose gel, as little as 10 pg of template DNA could be used to visualize the PCR products, and quantitative determination was possible at the levels of 10 pg to 100 ng template DNA. For the semi-quantitative determination of microbial changes during Kimchi fermentation, total DNAs from the 2 h-cultured microflora of Kimchi were extracted for 16 days and equal amounts of DNA templates were used for PCR. The intensities of DNA bands obtained from PCR using Leuconostoc-specific and Lb. plantarum-specific primer sets marked a dramatic contrast at the 1 ng and 100 ng template DNA levels during Kimchi fermentation, respectively. As the fermentation proceeded, the intensity of the band for Leuconostoc species increased sharply until the 5th day and the levels was maintained until the 11 th day. The sharp increase for Lb. plantarum occurred after 11 days with the decrease of Leuconostoc species. The results of this study indicate that Leuconostoc species were the major microorganisms at the beginning of Kimchi fermentation and reach their highest population during the optimum ripening period of Kimchi.