• Animal Bioscience
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• v.35 no.12
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• pp.1871-1880
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• 2022

Objective: The primary goal was to identify the effectiveness of chemical or biological additives in delaying the deterioration of early-harvested wilted rye silage after exposure to air. Methods: Rye harvested as a whole plant at the early heading stage was wilted for 24 h. The wilted forage was divided into treatments including sodium diacetate (SDA) at 3 (SDA3) and 6 g/kg (SDA6), Lactobacillus plantarum (LP), L. buchneri (LB), or their equal mixture (LP+LB) at 1×10⁶ colony-forming unit/g fresh matter. Results: After 60 d of conservation in 20-L silos, lactic acid was greater in LP and LP+LB silages than other treatments (102 vs 90.2 g/kg dry matter [DM]). Acetic acid was greatest in SDA6 (32.0 g/kg DM) followed by LB (26.1 g/kg DM) and was lowest in LP treatment (4.73 g/kg DM). Silage pH was lower with microbial inoculation and the lowest and highest values were observed in LP and untreated silages, respectively. After 60 d, neutral detergent fiber concentration was lowest in SDA6 silages, resulting in the greatest in vitro DM digestibility (846 g/kg DM). Aerobic stability was longest in SDA6 (176 h) followed by LB treatment (134 h). Instability after aerobiosis was greatest in LP silages (68 h), about 8 h less than untreated silages. After aerobic exposure, yeast and mold numbers were lowest in SDA6 silages, resulting in DM loss minimization. Exhaustion of acetic acid and lactic acid after aerobic exposure was lowest with SDA6 but greatest with untreated and LP silages. Conclusion: Treatment of early-cut wilted rye forage with SDA at 6 g/kg resulted in silages with higher feeding value and fermentation quality, and substantially delayed deterioration after aerobic exposure, potentially qualifying SDA at this load for promotion of silage quality and delaying aerobic spoilage of early-harvested (low DM) rye forage.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.2
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• pp.332-338
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• 2020

Objective: Aim of this study was to evaluate the influence of freeze-dried acid whey addition and the use a game meat (fallow deer) on a microbial content and the biogenic amines formation in dry fermented sausages. Methods: The experiment involved dry fermented sausages made in two variants from beef and from fallow deer. Each variant was divided into five groups: control (with a curing mixture), reference (with a sea salt), sample with a liquid acid whey and two samples with the addition of reconstituted freeze-dried acid whey in different concentrations. Changes in lactic acid bacteria (LAB), Enterobacteriaceae content and biogenic amines content were determined. Results: The microbial content changes suggest that addition of acid whey slightly affected LAB content in comparison with the control and reference sample, but the addition of freezedried acid whey resulted in a reduction of Enterobacteriaceae content in the sausages from fallow deer or a similar level in the beef sausages compared with the control and reference sample. Both changes in LAB and Enterobacteriaceae content were more evident in case of sausages made from fallow deer. Addition of acid whey (liquid and a higher amount of freezedried) and use of fallow deer meat to produce the sausages resulted in a significant reduction of total biogenic amines content. Conclusion: The addition of acid whey (liquid and higher amount of freeze-dried) resulted in a significant reduction of total biogenic amines content in dry fermented sausages made from fallow deer meat.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.24-29
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• 2013

In the present study, the effects of prebiotics and prebiotics+probiotics on intestinal microflora and fermentation products were evaluated in a pig in vitro fermentation model. The substrates used in this study were iso-malto oligosaccharide (IMO), partially digested chicory-inulin (CI), raffinose (RA), and cyclodextrin (CD) as prebiotics and Lactobacillus reiteri as probiotics. For a pig in vitro fermentation, the experimental diet for growing pigs was predigested using digestive enzymes secreted by small intestine and this hydrolyzed diet was mixed with a buffer solution containing 5% fresh swine feces. The mixture was then incubated with either prebiotics or prebiotics+probiotics for 24 h. Samples were taken at 24 h, and viable counts of microflora, gas, pH, volatile organic compounds (VOCs) and short-chain fatty acid (SCFA) were analyzed. The viable count of Enterobacteriaceae was significantly decreased (p<0.001) in all treatments containing prebiotics and prebiotics+probiotics when compared to the control. However, the number of lactic acid bacteria increased in the prebiotics and prebiotics+probiotics treatment. The pH values in the fermentation fluid decreased in all treatments when compared to the control, and their effects were greater in the prebiotics+probiotics group than prebiotics group. Fermentation with prebiotics resulted in a reduction in malodorous compounds such as ammonia, hydrogen sulfide and skatole when compared to the prebiotics+probiotics group. Short-chain fatty acid production was also higher for treatment with prebiotics+probiotics than treatment with prebiotics. In conclusion, the results of this study demonstrated that fermentation with prebiotics was effective in reducing the formation of malodorous compounds and prebiotics+probiotics was effective in increasing lactic acid bacteria and SCFA and reducing the pH. Moreover, further studies will be needed to determine whether the results observed in the in vitro model would occur in pigs that ingest these prebiotics or probiotics.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.107-107
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• 2017

3D bioprinting is a technology to produce complex tissue constructs through printing living cells with hydrogel in a layer-by-layer process. To produce more stable 3D cell-laden structures, various materials have been developed such as alginate, fibrin and gelatin. However, most of these hydrogels are chemically bound using crosslinkers which can cause some problems in cytotoxicity and cell viability. On the other hand, thermosensitive hydrogels are physically cross-linked by non-covalent interaction without crosslinker, facilitating stable cytotoxicity and cell viability. The examples of currently reported thermosensitive hydrogels are poly(ethylene glycol)/poly(propylene glycol)/poly(ethylene glycol) (PEG-PPG-PEG) and poly(ethylene glycol)/poly(lactic acid-co-glycolic acid) (PEG/PLGA). Chitosan, which have been widely used in tissue engineering due to its biocompatibility and osteoconductivity, can be used as thermosensitive hydrogels. However, despite the many advantages, chitosan hydrogel has not yet been used as a bioink. The purpose of this study was to develop a bioink by chitosan hydrogel for 3D bioprinting and to evaluate the suitability and potential ability of the developed chitosan hydrogel as a bioink. To prepare the chitosan hydrogel solution, ${\beta}-glycerolphosphate$ solution was added to the chitosan solution at the final pH ranged from 6.9 to 7.1. Gelation time decreased exponentially with increasing temperature. Scanning electron microscopy (SEM) image showed that chitosan hydrogel had irregular porous structure. From the water soluble tetrazolium salt (WST) and live and dead assay data, it was proven that there was no significant cytotoxicity and that cells were well dispersed. The chitosan hydrogel was well printed under temperature-controlled condition, and cells were well laden inside gel. The cytotoxicity of laden cells was evaluated by live and dead assay. In conclusion, chitosan bioink can be a candidate for 3D bioprinting.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.5
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• pp.660-664
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• 2003

An attempt was made to evaluate the effects of total mixed rations (TMR) containing 17.5% forage neutral detergent fiber (NDF) from paragrass, paragrass+cassava chips and corn silages on the performance of dairy cows in the tropics. Experimental dietary treatments contained a similar content of total NDF, total non-fiber carbohydrates, crude protein and energy. Maximum and minimum temperature humidity index during the experimental period were 79.1-80.6 and 66.8-68.6, respectively. Among silage sources, there were no differences (p>0.05) in concentrations of acetic and propionic acids and butyric acid was undetectable. Concentration of lactic acid was higher (p<0.01) in corn silage but its pH was lower (p<0.01) than in paragrass and paragrass+cassava silages. Dairy cows on TMR containing corn silage not only gained more weight (161 and 46 vs. -189 g/d) but also consumed more feed (18.47, 15.84 and 14.49 kg/d), and produced more milk (23.89, 22.03 and 20.83 kg/d), 4% fat corrected milk (25.47, 24.05 and 22.02 kg/d), solids-not-fat (1.99, 18.3 and 1.73 kg/d) and total solid (3.10, 2.85 and 2.64 kg/d) compared with those on TMR containing paragrass+cassava and paragrass silages, respectively (p<0.01). Dairy cows on TMR containing paragrass+cassava silage were better in these respects (p<0.01). These results suggest that in formulating diets on an equal NDF basis for different forage qualities, diets higher in forage quality can stimulate higher DMI for dairy cows in the tropics and thus improve productivity.

• Microbiology and Biotechnology Letters
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• v.41 no.4
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• pp.442-448
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• 2013

Lactic acid bacteria (LAB) are a representative group of probiotics and used in many fermented foods and beverages. Several recent studies have shown that LAB are present in makgeolli which is a traditional Korean alcoholic beverage. However, most LAB are intolerant of more than 6% (v/v) alcohol concentrations. For this reason, alcohol-tolerant LAB are isolated from kimchi, makgeolli and nuruk using alcohol containing selective media. After being cultured in MRS broth containing 13% (v/v) alcohol, the two strains which showed the highest increasing O.D values, were finally selected. As results of 16S rRNA gene sequencing and biochemical characterization using an API kit, the two species were identified as Pediococcus acidilactici K3 and S1. In addition, the identified two strains produced bacteriocins against Staphylococcus aureus. When compared with the P. acidilactici type strain, the two selected strains possessed two to three time higher growth on 12-13% (v/v) alcohol containing MRS broth. The viability of P. acidilactici K3 and S1 when inoculated in makgeolli and stored at $10^{\circ}C$ did not decrease through a period of one month indicating that the selected strains can be used for LAB containing makgeolli.

• Food Science of Animal Resources
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• v.35 no.1
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• pp.143-148
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• 2015

Yogurt powder is fermented milk processed in the form of dry yogurt, and has advantages such as stability, storability, convenience, and portability. China and Vietnam are important export target countries because of the increased demand for dairy products. Therefore, we surveyed dairy product standardization in order to establish an export strategy. Lactic acid bacteria counts are unregulated in Korea and Vietnam. In China, lactic acid bacteria counts are regulated at $1{\times}10^6$ colonyforming units (CFU)/mL and detected at $6.24{\pm}0.33\;Log\;CFU/mL$. All three countries have regulated standards for total bacterial counts. In China, total bacterial counts of milk powder are regulated to n=5, c=2, m=50,000, M=200,000 and detected at $6.02{\pm}0.12\;Log\;CFU/mL$, exceeding the acceptable level. Lactic acid bacterial counts appeared to exceed total bacterial counts. Coliform group counts, Staphylococcus aureus, Listeria monocytogenes, and Salmonella species were not detected. Acidity is not regulated in Korea and Vietnam. In China, acidity was regulated to over $70^{\circ}T$ and detected $352.38{\pm}10.24^{\circ}T$. pH is unregulated in all three countries. pH was compared to that of general fermented milk, which is 4.2, and that of the sample was $4.28{\pm}0.01$. Aflatoxin levels are not regulated in Korea and China. In Vietnam, aflatoxin level is regulated at 0.05 ppb. Therefore, all ingredients of the yogurt powder met the safety standards. This data obtained in this study can be used as the basic data in assessing the export quality of yogurt powder.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.4
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• pp.585-594
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• 2018

Objective: This study was to determine the bacterial diversity and monitor the community dynamic changes during storage of vacuum-packaged sliced raw beef as affected by Lactobacillus sakei and Lactobacillus curvatus. Methods: L. sakei and L. curvatus were separately incubated in vacuumed-packaged raw beef as bio-protective cultures to inhibit the naturally contaminating microbial load. Dynamic changes of the microbial diversity of inoculated or non-inoculated (control) samples were monitored at $4^{\circ}C$ for 0 to 38 days, using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Results: The DGGE profiles of DNA directly extracted from non-inoculated control samples highlighted the order of appearance of spoilage bacteria during storage, showing that Enterbacteriaceae and Pseudomonas fragi emerged early, then Brochothrix thermosphacta shared the dominant position, and finally, Pseudomonas putida showed up became predominant. Compared with control, the inoculation of either L. sakei or L. curvatus significantly lowered the complexity of microbial diversity and inhibited the growth of spoilage bacteria (p<0.05). Interestingly, we also found that the dominant position of L. curvatus was replaced by indigenous L. sakei after 13 d for L. curvatus-inoculated samples. Plate counts on selective agars further showed that inoculation with L. sakei or L. curvatus obviously reduced the viable counts of Enterbacteraceae, Pseudomonas spp. and B. thermosphacta during later storage (p<0.05), with L. sakei exerting greater inhibitory effect. Inoculation with both bio-protective cultures also significantly decreased the total volatile basic nitrogen values of stored samples (p<0.05). Conclusion: Taken together, the results proved the benefits of inoculation with lactic acid bacteria especially L. sakei as a potential way to inhibit growth of spoilage-related bacteria and improve the shelf life of vacuum-packaged raw beef.

• Journal of Animal Science and Technology
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• v.54 no.4
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• pp.299-305
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• 2012

This study was conducted to compare the microbial and physico-chemical quality characteristics in Kimchi-fermented sausages added with sodium nitrite (SN) and green tea extract (GTE). The sausages were fermented at $24^{\circ}C$/RH 89% for 17 hr and then dried at $10^{\circ}C$/RH 70~80% for 9 days. The total bacteria count, lactic acid bacteria count and pH value ranged from 8.7 Log CFU/g sausage, 8.1~8.3 Log CFU/g sausage and 4.35~4.36, respectively, at 9 d of ripening, but did not show significant differences during ripening among all sausages. The lipid oxidation (TBARS) was inhibited by both GTE and SN, but GTE had lower (p<0.05) inhibitory effect, compared with SN. The $b^*$ value of GTE-added sausage was higher than that of the control sausage, but $a^*$ and $b^*$ values of SN-added sausage remained higher than other sausages during ripening. Therefore, it had lower effect on lipid oxidation and color stabilities than SN while GTE improved the lipid oxidation stability in Kimchi-fermented sausage. However, both GTE and SN did not influence the growth of lactic acid bacteria.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.631-636
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• 2002

Lethality of high intensity light pulse on the pre-determined microbial populations has been investigated. Prior to the treatment, Lactobacillus plantarum, Lactobacillus brevis, Leuconostoc mesenteroides and Pediococcus pentosaceus were cultivated separately onto the surface of Lactobacilli MRS agar. Pre-determined microbial populations were applied to the test media and these sample were exposed to high intense light source with an exposure time ranging from 1 to $2500\;{\mu}s$. Results showed that at least 200 light pulses of $1\;{\mu}s$ duration were required to reduce L. Plantarum cells by 90% at 25 kV, the greater the number of light pulses, the larger the reduction in viable cell numbers. Viable cells of L. plantarum and the others were reduced by more than 5 and 6 log cycles at the upper exposure level of $750\;{\mu}s$, respectively. These study shows that pulsed light emissions can significantly reduce populations of lactic acid bacteria on exposed surface with exposure times. Killing efficiency for L. plantarum significantly increased with decreasing the distance between the lamp and the surface of samples.