• Asian-Australasian Journal of Animal Sciences
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• v.33 no.7
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• pp.1103-1112
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• 2020

Objective: To measure whether a microbial additive could effectively improve the fermentation quality of delayed-sealing (DS) silage, we studied the effects of inoculants of lactic acid bacteria (LAB) and cellulase enzyme on microbial populations, ensiling characteristics, and spoilage loss of DS silage of Napier grass in Africa. Methods: Quick-sealing (QS) and DS silages were prepared with and without LAB (Lactobacillus plantarum) inoculant, cellulase enzymes, and their combination. The QS material was directly chopped and packed into a bunker silo. The DS material was packed into the silo with a delay of 24 h from harvest. Results: In the QS silage, LAB was dominant in the microbial population and produced large amounts of lactic acid. When the silage was treated with LAB and cellulase, the fermentation quality was improved. In the DS silage, aerobic bacteria and yeasts were the dominant microbes and all the silages were of poor quality. The yeast and mold counts in the DS silage were high, and they increased rapidly during aerobic exposure. As a result, the DS silages spoiled faster than the QS silages upon aerobic exposure. Conclusion: DS results in poor silage fermentation and aerobic deterioration. The microbial additive improved QS silage fermentation but was not effective for DS silage.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.6
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• pp.832-840
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• 2014

This study aimed to investigate the effects of storage duration and temperature on the characteristics of wet brewers grains (WBG) as feeds for ruminant animals. Four storage temperatures ($5^{\circ}C$, $15^{\circ}C$, $25^{\circ}C$, and $35^{\circ}C$) and four durations (0, 1, 2, and 3 d) were arranged in a $4{\times}4$ factorial design. Surface spoilage, chemical composition and microorganism density were analyzed. An in vitro gas test was also conducted to determine the pH, ammonia-nitrogen and volatile fatty acid (VFA) concentrations after 24 h incubation. Surface spoilage was apparent at higher temperatures such as $25^{\circ}C$ and $35^{\circ}C$. Nutrients contents decreased concomitantly with prolonged storage times (p<0.01) and increasing temperatures (p<0.01). The amount of yeast and mold increased (p<0.05) with increasing storage times and temperatures. As storage temperature increased, gas production, in vitro disappearance of organic matter, pH, ammonia nitrogen and total VFA from the WBG in the rumen decreased (p<0.01). Our results indicate that lower storage temperature promotes longer beneficial use period. However, when storage temperature exceeds $35^{\circ}C$, WBG should be used within a day to prevent impairment of rumen fermentation in the subtropics such as Southeast China, where the temperature is typically above $35^{\circ}C$ during summer.

• Korean Journal of Food Science and Technology
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• v.7 no.2
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• pp.61-68
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• 1975

This study was conducted (1) to isolate the film-forming yeast from the commercially available soy sauce, (2) to identify the state of soy sauce fermentation by the use of yeasts, (3) to confirm characteristics of yeasts. The result were as follows. 1. These yeast strains in the soy sauce fermentation test showed full fermentation of whole sugar content, reduction of the pure extract and relative reduction in total nitrogen. Soy sauce color was somehow faded to lower the stability of soy sauce. 2. In anti-fungal activity test butylparaben at a higher level 60 ppm., sodium propionate 2,400 ppm, sodium benzoate 800 ppm., menadion 165 ppm, showed their anti-fungal effect, while alcohol did not show the effect in the 3% additive group. 3. The optimum sodium chloride concentration for these strains in the 2% G.Y.P. medium was 5% and optimum temperature was $30^{\circ}C$. The extinction temperature was $62^{\circ}C$ for strain No-1 and No-3, and was $65^{\circ}C$ for No-2 and No-4. 4. The film-forming soy sauce turned out in the gas chromatogram to possess much flavor of low boiling point as compared with the standard. These flavors were considered due to flavor spoilage of the soy sauce. 5. These isolated yeasts were identified Saccharomyces rouxii (film-forming yeast) in the Lodder's taxanomic study.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.630-634
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• 2001

The effect of chitosan on the quality of processed milk was investigated to minimize the microbial spoilage occurred by contaminant bacteria and yeast. Yeast and bacteria isolated from commercial processed milk were identified as Saccharomyces cerevisiae and Pseudomonas fluoresence by Api 20C and 20E Aux kit, respectively. The growth of isolated yeast and bacteria inhibited in YM broth and TSB containing 0.03% chitosan at $25^{\circ}C$ and $37^{\circ}C$ for 24hour, respectively. Viable cells of processed milk artificially contaminated with Saccharomyces cerevisiae and Pseudomonas fluoresence were reduced about 2~3 l$og_{10}$ cycle by addition of 0.03% chitosan pH, acidity and total bacteria were changed from after storage for 10 day at $4^{\circ}C$, 7 day at 1$0^{\circ}C$ and 1day at $25^{\circ}C$in chitosan no added processed milk during storage for 15day. But, The change of physico-chemical and microbiological charcteristics could not observe in 0.3% chitosan added processed milk during storage 15 day at $4^{\circ}C$, 1$0^{\circ}C$ and $25^{\circ}C$, respectively. The sensory quality of processed milk with 0.3% chitosan was different significantly from control in taste, texture and overall acceptability(p<0.05).

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1358-1364
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• 2000

A mixed culture of bacteriocin-producing lactic acid bacteria and yeast was used to prepare unique fermented fruit and vegetable beverage which contains bacteriocin. Fruit and vegetable broth fermented by Lactococcus lactis 11454 showed inhibitory activity against foodborne pathogens such as Listeria monocytogens and Staphylococcus aureus, and Streptococcus mutans which is a major causative agent for dental caries. Bacteriocin was detected at the end of fermentation of fruit and vegetables and its antimicrobial activity was stable for 5 weeks during storage at $4^{\circ}C$. These results suggest that the presence of bacteriocin in beverages during fermentation and storage will provide a safeguard against foodborne pathogens and spoilage bacteria. To improve flavor of the fermented broth, post-fermentation of the fermented broth was carried out at $4^{\circ}C$ by using yeast isolated from raw material mixture. Total acidity of the post-fermented broth was slightly decreased, but significant increase in the concentration of succinic acid was observed in the post-fermented broth. It was also observed that bitter and disagreeable taste compounds such as phthalates were decreased, and mild acidic and fruity flavor esters and alcohols were increased by the post-fermentation of the fermented broth with yeast.

• Journal of Microbiology and Biotechnology
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• v.22 no.8
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• pp.1101-1106
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• 2012

Market fresh makgeolli was stored at different temperatures of $4^{\circ}C$ and $25^{\circ}C$ to assess the change of the microbial diversity according to the storage temperature and period. Yeast counts increased until day 3 of storage and decreased thereafter. General and lactic acid bacterial counts continuously increased during storage. The data indicated that the control of growth of microorganisms, particularly general bacteria and lactic acid bacteria (LAB), is essential. Total acid levels started to decrease in the makgeolli stored at $4^{\circ}C$, and increased from day 6 of storage in the makgeolli stored at $25^{\circ}C$. The increase of total acid in the non-refrigerated condition greatly affected the quality of makgeolli. In both the fresh makgeolli samples stored at $4^{\circ}C$ and $25^{\circ}C$, yeast (Saccharomyces cerevisiae) and molds (Aspergillus tubingensis, Candida glaebosa, and Aspergillus niger) were noted. Denaturing gradient gel electrophoresis (DGGE) band patterns were almost constant regardless of the storage period. As for bacteria, Lactobacillus crustorum, L. brevis, and Microlaena stipoides were found in the makgeolli stored at $4^{\circ}C$, and L. crustorum, Lactobacillus sp., L. plantarum, L. brevis, L. rhamnosus, and L. similis were found in the makgeolli stored at $25^{\circ}C$. In particular, in the makgeolli stored at $25^{\circ}C$, L. crustorum and L. plantarum presented dark bands and were identified as the primary microorganisms that affected spoilage of fresh makgeolli.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.9
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• pp.1274-1280
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• 2015

This study was conducted to assess the effects of microbial and chemical combo additives on nutritive values, fermentation indices and aerobic stability of whole crop barley silage. Barley forage (Youngyang) was harvested at about 30% dry matter (DM) by treatments, chopped to 5 cm length and treated with distilled water only (CON), Lactobacillus plantarum (INO), propionic acid (PRO) or an equal mixture of INO and PRO (MIX). Barley forages were ensiled in 4 replications for 0, 2, 7, and 100 days. On 100 days of ensiling, MIX silage had higher (p<0.05) in vitro DM digestibility than CON silage, but lower (p<0.05) acid detergent fiber concentration. The pH in all treated silages was lower (p<0.05) than CON silage. The MIX silage had higher (p<0.05) lactate concentration and lactate to acetate ratio than in CON, but lower (p<0.05) yeast count. Aerobic stability in CON, PRO, and MIX silages were higher (p<0.05) than in INO silage. It is concluded that microbial and chemical combo additives using L. plantarum and propionic acid could efficiently improve nutritive values of barley silage in terms of increased in vitro DM digestibility compared to other treatments. In addition, all treatments except CON reduced yeast count which is the initiate microorganism of aerobic spoilage.

• Journal of Microbiology and Biotechnology
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• v.11 no.4
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• pp.577-584
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• 2001

An antimicrobially active bacterium which was identified as Bacillus brevis, was isolated from kimchi. The antimicrobial activity was found against various Gram-positive and Gram-negative bacteria including some pathogens food-spoilage microorganisms, and some yeast strains. The antimicrobial activity was especially strong against Bacillus anthracis and Shigella dysenteriae. The strong activity was observed during an early stationary phase in the culture when incubated at $37^{\circ}C$ with initial medium pH of 6.8. The antimicrobial activity was found to be stable at $90^{\circ}C$ for 30 min and in the pH range of 3-11, and it was insensitive to organic solvents including acetone, acetonitrile, ethanol, and methanol. Analysis of the bacterocin on tricine-sodium dodecyl sulfate-polyacrylamide gel suggested a molecular mass of approximately 4.5-6.0 kDa. The antimicrobial substance was characterized as a bacteriocin, because of its proteinaceous nature and low molecular weight. The bacteriocin could potentially be used as a food preservative, because of its thermostable property and broad antimicrobial spectrum.

• Microbiology and Biotechnology Letters
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• v.8 no.3
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• pp.155-166
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• 1980

Studies have teen undertaken to investigate the degree of microbial contamination in the subsidiary materials which have been known as an important source of microorganisms associated with spoilage of fish sausage and fish paste products. Twenty hinds of food ingredients including starch, spices and condiments, 59 samples in total collected from commercial fish sausage processing plants and supermarket in the period of July to October 1979, were examined for standard plate count, coliform and fecal coliform, mold and yeast, thermoduric microorganisms, aerobic sporeformers (mesophilic and thermophilic), anaerobic sporeformers (mesophilic and thermophilic) and sulfide spoilage anaerobes. The results obtained are summarized as follows. 1. Among the food ingredients examined, corn starch, black pepper, hot pepper, onion, garlic, ginger, beef extract and frank marked high bacterial contamination with general and sporeforming microorganisms. And bacterial content of marked samples were generally higher than that of the samples from plants. 2. The high standard plate count caused by high content of these bacteria like thermoduric, mesophilic or thermophilic sporeforming aerobes. 3. Bacterial content of food ingredients such as black pepper and beef extract being used in plants, and black pepper, hot pepper, onion and garlic from the market were exceeded the bacterial standards being enforced in Japan and U. S. A. 4. Average standard plate count was in the range of 10$^4$to 10$^{5}$ /g for black pepper, wheat flour, onion and garlic collected from plants, and 10$^{5}$ to 10$^{7}$ /g for black pepper, hot pepper, onion and garlic from market. No plate count was observed in pepper essence and coloring material. 5. Coliform organism was detected in starch, black pepper, hot pepper, onion, garlic, ginger and gluten that showed high standard plate but no fecal coliform in the samples except black pepper and hot pepper. 6. Average mold and yeast count was 140 to 460/g for corn starch, wheat flour and black pepper from plants, and 10$^3$/g for black pepper and hot pepper from market. No count was observed in the other ingredients. 7. Sulfide spoilage sporeforming anaerobes boiled for 5 min. at 10$0^{\circ}C$ and incubated at 55$^{\circ}C$ was not detected in all the samples examined.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.1
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• pp.111-116
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• 2007

We examined the antimicrobial activity of electrolyzed alkaline water against spoilage microorganisms in rice warehouses. Dominant microbial species were isolated from paddy, dust and air samples of three different warehouses located in Gyeongnam. We used electrolyzed alkaline water (EW) manufactured over various treatment times. The acidities (pH) of EW treated for 30 sec, 1, 2, 3, and 4 min were 8.89, 8.91, 9.20, 9.35, and 9.22, respectively. HClO contents were 150.7, 314.2, 191.8, 104.1, and 255.3 ppm, respectively. EW inhibited bacteria, yeasts, and molds; also, it inhibited three yeast species strongly. The antimicrobial effects of EW increased as pH values and HClO contents increased. EW obtained after 30 sec treatment retained the antimicrobial activities after 14 days whereas EW obtained after 1 and 2 min treatments retained the antimicrobial activities after 21 and 24 days, respectively.