• 농업과학연구
• /
• 제40권2호
• /
• pp.131-137
• /
• 2013

The inhibitory effect of citrus peel extract, onion peel extract, calcium lactate and phosvitin on microbial growth was investigated in seasoned chicken breast meat during aerobic storage at $4^{\circ}C$, $10^{\circ}C$ and $20^{\circ}C$. Citrus peel and onion peel extract significantly improved (p<0.05) the microbial quality of the sample by reducing the initial counts of the microbial flora compared to control and other two treatments. Data clearly revealed that the counts of the total aerobic bacteria significantly increased with the increase in storage temperature. The shelf life of all samples stored under $20^{\circ}C$ was less than 6 days, while the shelf life of citrus and onion treatment can be extended more than 9 days at $4^{\circ}C$ and more than 6 days at $10^{\circ}C$ in aerobic storage condition. These results indicated that citrus and onion peel extracts are efficient treatment methods to prevent microbial spoilage of seasoned chicken products during storage at $4^{\circ}C$. However, there was an adverse effect of addition of citrus and onion peel extract on several sensory attributes which need to be improved by reformulation of seasoning.

• 한국수산과학회지
• /
• 제54권5호
• /
• pp.751-760
• /
• 2021

This study investigated the changes in water quality parameters and microbial colonies when ozone was applied to a semi-recirculating aquaculture system (semi-RAS) for the olive flounder Paralichthys olivaceus (500 g in average weight). Concentrations of ozone-produced oxidants (OPO) in rearing tanks were maintained at 0, 0.014, 0.025 mg/L as Cl₂ for 26 days. Except total ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, phosphate phosphorus, chemical oxygen demand, and total suspended solids decreased significantly with increasing OPO concentration in daily and weekly monitoring (P<0.05). Colony forming unit (CFU) counts of heterotrophic marine bacteria decreased in an OPO concentration-dependent manner. Overall reduction rates of microbial colonies in the treatments were 80% higher than those of the control (P<0.05). During the experiment, the OPO concentration-driven ozonation was reliably practiced without any adverse effects on the animals cultured in semi-RAS. Considering the biohazard, operating cost, and stability of ozonation, an OPO concentration of 0.014 mg/L would be sufficient to control water quality parameters and microbial colonies in a semi-RAS.

• 한국응용과학기술학회지
• /
• 제37권4호
• /
• pp.778-785
• /
• 2020

본 연구의 목적은 포졸란의 항생제 내성균과 장내 유해 미생물 억제에 관한 체외배양 항균 활성을 조사하는 것이었다. 대조군 (CON, 포졸란 무첨가 대조군)과 DP0.3 (증류수와 포졸란 분말 0.3%를 혼합하여 제조한 배지군), DP0.5 (증류수와 포졸란 분말 0.5%를 혼합하여 제조한 배지군), PE (포졸란 분말 추출물을 이용하여 제조한 배지군)으로 구분하였다. Lacctobacillus casei 균수는 CON과 비교할 때 DP0.3 처리군에서 유의하게 높았으나 (P<0.05) 기타 처리구 사이의 차이는 없었다. Clostridium butyricum, E. coli, Salmonella typhimurium 균수는 CON과 비교할 때 포졸란 처리구가 유의하게 낮았다 (P<0.05). Clostridium butyricum, Salmonella typhimurium 균수는 DP0.3, DP0.5와 PE 사이, E. coli 균수는 DP0.5와 PE 사이의 유의차가 있었다 (P<0.05). MRSA와 VRE의 균수는 CON과 비교할 때 포졸란 처리구가 유의하게 낮았다 (P<0.05). MRSA 균수는 DP0.5와 DP0.3, PE 사이의 차이가 있었고, VRE 균수는 PE> DP0.3> DP0.5> CON 처리구 순서로 유의하게 높았다(P<0.05). 이와 같은 결과를 통해 포졸란의 항생제 내성균 및 장내 유해 미생물에 대한 항균활성이 확인됨에 따라 가축용 천연항균제, 보조사료 규산염제로써의 활용이 가능할 것으로 보인다.

• 한국식품위생안전성학회지
• /
• 제15권3호
• /
• pp.252-255
• /
• 2000

본 연구는 육류와 가금육, 유가공 공장의 생산라인에서 미생물 오염수준을 측정함에 있어 ATP bioluminescence법이 적용될 수 있는지를 조사하기 위해 수행되었다. 도축장, 도계장, 유가공 공장 생산라인에서 시료를 채취하였으며 ATP bioluminescence법과 표준평판법을 병행하여 나타난 결과치(log RLU/ml, CFU(log/ml))를 상호 비교하여 상관계수를 측정하였다. 모든 시료(n=408)에서의 상관계수는 0.93이었으며 이중 쇠고기, 돼지고기, 닭고기는 0.93(n=220), 육, 유가공장 생산라인 또한 0.93(n=187)로 비교적 높게 나타나 ATP bioluminescence법이 기존의 표준평판법에 비해 상관계수가 높으므로 식품생산현장에서 신속하고 편리하게 세균의 오염여부를 판정할 수 있는 방법이라고 생각된다.

• Journal of Microbiology and Biotechnology
• /
• 제25권12호
• /
• pp.2049-2057
• /
• 2015

Various salt concentrations (1.0%, 1.3%, 1.6%, 1.9%, and 2.1% labeled as sample A, B, C, D, and E, respectively) were investigated for microbial diversity, identification of Lactic Acid Bacteria (LAB) in salted kimchi cabbage, prepared under laboratory conditions. These samples were stored at 4°C for 5 weeks in proper aluminum-metalized pouch packaging with calcium hydroxide gas absorber. A culture-independent method known as polymerase chain reaction - denaturing gradient gel electrophoresis was carried out to identify LAB distributions among various salt concentration samples that had identified 2 Weissella (W. confusa and W. soli), 1 Lactobacillus (Lb. sakei), and 3 Leuconostoc (Lc. mesenteroides, Lc. lactis, and Lc. gelidum) in the overall kimchi samples. The pH, titratable acidity, viable cell counts, and coliform counts were not affected by salt variations. In order to assess sensory acceptance, the conducted sensory evaluation using a 9-point hedonic scale had revealed that samples with 1.3% salt concentration (lower than the manufacturer's regular salt concentration) was more preferred, indicating that the use of 1.3% salt concentration was acceptable in normal kimchi fermentation for its quality and safety. Despite similarities in pH, titratable acidity, viable cell counts, coliform counts, and LAB distributions among the various salt concentrations of kimchi samples, the sample with 1.3% salt concentration was shown to be the most preferred, indicating that this salt concentration was suitable in kimchi production in order to reduce salt intake through kimchi consumptions.

• Asian-Australasian Journal of Animal Sciences
• /
• 제21권11호
• /
• pp.1635-1641
• /
• 2008

This study investigated the effects of solid-state fermentation of a compound pig feed on its microbial and nutritional characteristics as well as on pig performance and nutrient digestibility. A mixed culture containing Lactobacillus fermentum, Saccharomyces cerevisae and Bacillus subtilis was used for solid-state fermentation and solid-state fermented feed samples were collected on days 0, 1, 2, 3, 5, 7, 10, 15, 20 and 30 for microbial counts and chemical analysis. Lactic acid bacteria increased rapidly during the first three days of fermentation and then slowly declined until day 10 and, thereafter, the counts were maintained at about 6.7 log cfu/g for the duration of the fermentation period. Enterobacteria also increased during the first two days, and then fell below the detectable level of the analysis (3.0 log cfu/g). The pH of the fermentation substrate declined from 6.1 at the start of fermentation to 5.7 by day 30. The water-soluble protein content increased from 8.2 to 9.2% while the concentration of acetic acid increased from 16.6 to 51.3 mmol/kg over the 30-day fermentation. At the end of the 30-day fermentation, the solid-state fermented feed was used in a pig feeding trial to determine its effects on performance and nutrient digestibility in growing-finishing pigs. Twenty crossbred barrows ($14.11{\pm}0.77kg\;BW$) were allotted into two dietary treatments, which comprised a regular dry diet containing antibiotics and a solid-state fermented feed based diet, free of antibiotics. There was no difference due to diet on pig performance or nutrient digestibility. In conclusion, solid-state fermentation resulted in high counts of lactic acid bacteria and low counts of enterobacteria in the substrate. Moreover, feeding a diet containing solid-state fermented feed, free of antibiotics, can result in similar performance and nutrient digestibility in growing-finishing pigs to a regular diet with antibiotics.

• 한국초지조사료학회지
• /
• 제42권4호
• /
• pp.264-269
• /
• 2022

본 연구에서는 미생물 첨가에 따라 거세한우 비육우 분의 이화학적 특성, 미생물 성상, 가스발생량 및 퇴비 부숙도에 미치는 영향을 규명하고자 수행하였다. 이상의 결과를 종합하면, 4주 후, 미생물 첨가구에서 수분, 유기물, 총질소 함량 및 pH가 낮았으며, 나머지 이화학적 특성에서는 차이가 나타나지 않았다. 유산균과 효모균 수는 증가하였으며, 대장균 수는 감소하였다. 12주 후, 미생물 첨가구에서 유산균과 고초균 수는 높았으나, 수분, 효모 및 대장균 수는 낮게 낮았다. 하지만 암모니아, 황화수소 발생량과 퇴비 부숙도는 미생물 첨가에 의한 효과가 나타나지 않았다. 따라서, 거세한우 분에 미생물을 첨가하면 유익균은 증가하고, 병원성 미생물은 감소하여, 비육우의 생산성은 증진될 것으로 사료되지만, 가스 발생량 및 퇴비 부숙도에 대한 추가적인 연구는 지속적으로 수행되어야 할 것으로 사료된다.

• 한국식품과학회지
• /
• 제32권4호
• /
• pp.828-833
• /
• 2000

흰떡과 생면의 저장성을 연장 시키기 위하여 주정 처리와 키토산 처리 및 주정과 키토산의 병용처리를 하여 저장기간에 따른 품질의 변화를 조사하였다. 흰떡의 경우 아무 처리를 하지 않은 대조구는 6일, 주정처리는 27일에 총세균수의 기준치인 $1{\times}10^{6}\;CFU/g$을 넘어섰으며 젖산 1% 용액을 사용한 경우는 20일에 $1{\times}10^{6}\;CFU/g$ 이상이 되었다. 그러나 키토산으로 처리했을 때에는 저장 76일 까지도 총세균수가 기준치 이하를 나타내어 주정처리를 한 경우보다 약 3배 정도의 저장성 연장 효과가 있음을 알 수 있었다. 생면의 경우 대조구와 주정처리구는 7일 만에 총세균수가 기준치를 넘었으며 키토산처리의 경우는 82일이 경과해도 $1{\times}10^{6}\;CFU/g$ 이하의 값을 나타내어 키토산 처리에 의한 저장성 연장 효과를 확인할 수 있었다.

• Journal of Microbiology and Biotechnology
• /
• 제27권5호
• /
• pp.995-1004
• /
• 2017

Culture-dependent methods, such as heterotrophic plate counting (HPC), are usually applied to evaluate the bacteriological quality of hemodialysis water. However, these methods cannot detect the uncultured or viable but non-culturable (VBNC) bacteria, both of which may be quantitatively predominant throughout the hemodialysis water treatment system. Therefore, propidium monoazide (PMA)-qPCR associated with HPC was used together to profile the distribution of the total viable bacteria in such a system. Moreover, high-throughput sequencing of 16S rRNA gene amplicons was utilized to analyze the microbial community structure and diversity. The HPC results indicated that the total bacterial counts conformed to the standards, yet the bacteria amounts were abruptly enhanced after carbon filter treatment. Nevertheless, the bacterial counts detected by PMA-qPCR, with the highest levels of $2.14{\times}10^7copies/100ml$ in softener water, were much higher than the corresponding HPC results, which demonstrated the occurrence of numerous uncultured or VBNC bacteria among the entire system before reverse osmosis (RO). In addition, the microbial community structure was very different and the diversity was enhanced after the carbon filter. Although the diversity was minimized after RO treatment, pathogens such as Escherichia could still be detected in the RO effluent. In general, both the amounts of bacteria and the complexity of microbial community in the hemodialysis water treatment system revealed by molecular approaches were much higher than by traditional method. These results suggested the higher health risk potential for hemodialysis patients from the up-to-standard water. The treatment process could also be optimized, based on the results of this study.

• Journal of Microbiology
• /
• 제41권3호
• /
• pp.262-265
• /
• 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.