• 한국축산식품학회지
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• 제36권5호
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• pp.617-625
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• 2016

Pastırma, a dry-cured meat product, is produced from the whole muscle and/or muscles obtained from certain parts of beef and water buffalo carcasses. The purpose of this study was to determine the effects of different levels of sodium nitrite on changes in the physicochemical and microbial quality during the production of pastırma. The changes in residual nitrite, salt, pH, moisture, thiobarbutiric acid reactive substances (TBARS), colour (L*, a*, b*), total aerobic mesophilic bacteria (TAMB), lactic acid bacteria (LAB), Micrococcus/Staphylococcus (M/S), mould-yeast (M-Y), and Enterobacteriaceae counts of pastırma with 0, 50, 100 and 150 ppm sodium nitrite were determined during the production. The nitrite levels and the production stages had significant effects (p<0.01) on residual nitrite, TBARS, pH, salt, and colour values. The TBARS values of the pastırma with nitrite were significantly lower (p<0.05) than the control. The final TAMB, LAB, M/S, and M-Y counts of pastırma with 150 ppm nitrite were significantly (p<0.05) lower than the control. Also, the a* (relative redness) values of control pastırma were significantly lower (p<0.05) than the pastırma with nitrite. The production stages had a significant effect (p<0.01) on the moisture.

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

• 한국환경과학회지
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• 제32권12호
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• pp.925-932
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• 2023

The objective of this study was to investigate the effects of microbial additive on the meat quality and fatty acid (FA) profiles of growing-finishing pigs. A total of 180 growing-finishing pigs (Landrace × Yorkshire × Duroc; mixed sex; 14 weeks of age; 58.0 ± 1.00 kg) were randomly distributed into three treatments with three pens consisting of 20 growing-finishing pigs per pen for 60 days. The experimental treatments were as follows: 0, 0.5, and 1.0% microbial additive. The crude protein, cooking loss, drip loss, water holding capacity, and shear force in loin muscle were no significant differences among treatments (p>0.05), except for the moisture and crude fat contents. The pH and TBARS of loin muscle shown no significant differences among treatments (p>0.05). However, the L^* and a^* values of loin muscle were the highest in the 1.0% supplementation group compared with the other treatments (p<0.05). The b^* value of loin muscle was the highest in the control group compared with the other treatments (p<0.05). Linolenic acid, eicosapentaenoic acid, docosapentaenoic acid, docosahexaenoic acid, and n-3 FAs contents of loin muscle were the highest in 1.0% supplementation group compared with the other treatments (p<0.05). In conclusion, using 1.0% microbial additive supplementation can improve meat quality by increasing polyunsaturated FA concentration and meat color in pig loins.

• Fisheries and Aquatic Sciences
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• 제27권1호
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• pp.23-34
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• 2024

While scientific information on the spatial variation of soda lake Microalgae is important to limnological studies, little information was reported from the Ethiopian Rift Valley Lake, Lake Chitu. This study aimed to understand the spatial distribution of the dominant Microalgae taxa in Lake Chitu, Ethiopia. The collection of samples and in situ measurements of some physico-chemical parameters were recorded at three sites for one cycle in November 2021. Fourteen species or genera of Microalgae were identified. Among those, Bacillariophyta were the most important with regard to species abundance and the rarest in species richness. Cyanophyta were the second-most important group in terms of species richness and rarity. Comparatively, all microalgae taxa were rare at both the anthropogenic areas (AA) and the flooding area (FA), which could be mainly due to intensive human and animal intervention and associated with extreme turbidity. Among Cyanophyta, Chroococcus minutus, Microcystis aeruginosa, and Spirulina platensis/fusiformis were predominant at both AA and FA, revealing their adaptation to less clear water and pollution. But S. platensis/fusiformis attained the highest abundance at the FA, indicating their preference for water in a highly nutrient-enriched area. We concluded that the spatial variation of microalgae diversity in relation to water quality parameters has implications for the importance of microalgae as a baseline indicator of water quality assessment tools in lakes.

• 한국축산식품학회지
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• 제28권5호
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• pp.675-680
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• 2008

The physical quality and microbial safety of Korean beef jerky was evaluated at various steps during its preparation. Microbial counts in raw beef demonstrated mesophillic bacteria at 4.20 Log CFU/g, psychrotrophic bacteria at 3.85 Log CFU/g, anaerobic bacteria at 4.90 Log CFU/g, and yeast and molds at 1.92 Log CFU/g. Spore-forming bacteria and coliforms were not detected in raw beef samples. Spices and spiced meats showed similar trends in microbial counts, demonstrating minimal microbial contamination during these stages of preparation. The final beef jerky product exhibited counts of mesophillic bacteria at 1.15-1.66 Log CFU/g, psychrotrophic bacteria at 1.15-1.66 Log CFU/g, and anaerobic bacteria at 0.81-1.72 Log CFU/g. Spore-forming bacteria, yeast and molds, and coliforms were not detected in beef jerky. Significant differences from added ingredients occurred for instron textural profile analysis traits for hardness. In general, Korean beef jerky with humectant and tenderizer had lower hardness than control (without humectant and tenderizer). Also, the sample added with 0.01% protease from Streptomyces griseus had lower hardness than all samples. All samples had 0.7l to 0.72 water activities, and the color and pH were not shown in significant changes of all samples.

• Preventive Nutrition and Food Science
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• 제9권2호
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• pp.121-125
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• 2004

Effects of chemical treatment with a citric acid solution or ozonated water on microbiological changes in lettuce and cabbage during storage were studied. Fresh lettuce and cabbage samples were cut into small pieces and treated by soaking in either ozonated water or a citric acid solution. After treatment, populations of total bacteria, yeast and mold, and E. coli were determined. Numbers of microorganisms increased during storage, but ozonated water and citric acid treatments retarded the increase in microbial growth. Among treatments, 1 % citric acid treatment was the most effective in terms of microbiological change and inhibition of polyphenoloxidase (PPO). For lettuce, citric acid treatment decreased the microbial growth overall by 1.5 log CFU/g and inhibited the PPO activity by 80%. These results indicate that chemical-treated lettuce and cabbage retained a better quality than those of the control during storage.

• 한국축산식품학회지
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• 제33권4호
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• pp.439-447
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• 2013

Time-temperature integrators (TTIs) are simple and cost-efficient tools which may be used to predict food quality. Enzymatic TTIs are devised to indicate food quality in the form of color alterations from green to red, based on the cumulative impacts of temperature and time period on the enzymatic reactions. In this study, the quality of ground beef patties was investigated for the parameters of pH levels, color, VBN, water holding capacity, and total microbial counts, depending on various storage temperatures (5, 15, and $25^{\circ}C$). TTIs were attached to the surface of the ground beef patties in order to evaluate the degree of correlating colorimetric changes with the determined quality parameters. Through the Arrhenius equation, activation energy and constant reaction rates of TTI, VBN, and total microbial counts were calculated as to observe the relationship between enzymatic reactions of the TTI and food spoilage reactions of the ground beef patties. VBN and total microbial counts were already increased to reach decomposition index (VBN: 20, total microbial count: 7-8 Log CFU/g) of meat at middle stage of storage period for each storage temperature. Although activation energy of TTI enzymatic reactions and food spoilage reactions of the ground beef patties were similar, the change of TTI color was not a coincidence for food spoilage at $5^{\circ}C$ and $15^{\circ}C$ of storage temperature. It was suggested that TTI should be designed individually for storage temperature, time, type of meat, or decomposition index of meat.

• 한국환경보건학회지
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• 제35권6호
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• pp.517-525
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• 2009

The water quality of Lake Shihwa had been rapidly deteriorating since 1994 due to wastewater input from the watersheds, limited water circulation and the lack of a wastewater treatment policy. In 2000, the government decided to open the tidal embankment and make a comprehensive management plan to improve the water quality, especially inflowing stream water around Shihwa and Banwol industrial complex. However, the water quality and microbial community have not as yet been fully evaluated. The purpose of this study is to investigate the influent water quality around the industrial area based on chemical and biological analysis, and collected surface water sample from the Siheung Stream, up-stream to down-stream through the industrial complex, Samples were collected in July 2009. The results show that the downstream site near the industrial complex had higher concentrations of heavy metals (Cu, Mn, Fe, Mg, and Zn) and organic matter than upstream sites. A combination of DGGE (Denaturing Gradient Gel Electrophoresis) gels, lists of K-WQI (Korean Water Quality Index), cluster analysis, MDS (Multi-Dimensional Scaling) and PCA (Principal Component Analysis) has demonstrated clear clustering between Siheung stream 3 and 4 and with a high similarity and detected metal reducing bacteria (Shewanella spp.) and biodegrading bacteria (Acinetobacter spp.). These results suggest that use of both chemical and microbiological marker would be useful to fully evaluate the water quality.

• 한국식품과학회지
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• 제31권5호
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• pp.1392-1396
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• 1999

우유의 저온살균시 품질손상의 원인이 되는 fouling발생을 극소화시키면서 균을 사멸시키기 위하여 마이크로파를 이용한 우유의 살균에 대한 연구를 시도하였다. 이에따라 연속식 마이크로파 HTST 시스템을 설계 제작한 후, 우유를 HTST$(72^{circ}C$, 15초)법으로 살균하되 열수만을 이용한 경우(MP0)와 마이크로파로 온도를 올린 후 열수에서 holding한 경우(MP1)와 마이크로파만을 활용한 경우(MP2)의 세가지로 구분하여 미생물의 사멸효과를 총생균수, 대장균수, 저온성세균수 및 phosphatase 활성으로 구분하여 비교해 보았다. 총균수와 저온성 세균수의 경우 세가지 HTST살균법 모두 살균후 초기균수의 3 log 정도 감소하는 살균효과를 보여주었다. 살균방법별 살균효과는 MP0>MP2>MP1의 순서를 보였고 유의차(p<0.05)도 있는 것으로 나타났으나 원유의 초기미생물수와 함께 통계처리할 경우는 살균방법 사이의 유의차는 보이지 않았다. 대장균과 phosphatase activity의 경우 세가지 HTST 살균법 모두 살균후 우유의 배양실험에서 대장균 집락이 확인되지 않거나 살균후 음성(negative)인 것으로 나타나 살균방법 사이의 살균효과에 차이가 없음을 확인시켜주었다. 따라서 마이크로파 단독처리(MP2) 또는 마이크로파로 승온시킨 후 원하는 온도에서 holding하는 병용법(MP1)을 활용할 경우 통상적 HTST법에서 문제가 되는 fouling을 방지하면서 거의 대등한 살균효과를 얻을 수 있을 것으로 예상하였다 얻어진 연구결과를 토대로 우유 및 타 액상식품의 살균에도 확대 적용할 수 있으리라 기대된다.

• 미생물학회지
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• 제49권2호
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• pp.150-155
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• 2013

Pyrosequencing을 이용하여 영산강 유역의 세균 군집 현황을 조사하였다. 영산강 본류 및 지천 14개 지점을 선정하여 5-7월동안 시료채취를 하였다. 총 42개의 시료를 가지고 총 989,380 reads을 얻었으며 taxonomic 분류와 OTU 분포도 분석을 실시하였다. Phylum 계층의 세균 구조 결과를 통해서 지천의 특성, 토지 이용, 시기적인 요인 등 환경적 요인에 따라 세균 군집 구조가 민감하게 변하는 경향을 나타내었다. 또한, OTU 분석을 근거한 오염원 추적기법(microbial source tracking; MST)을 통해 분변오염을 추적해보았다. Firmicutes가 가장 수질에 영향을 주는 taxa로 관찰되었다. 본 연구를 통해서, 현재 사용하는 수질 지표, BOD, pH 등에 더하여 pyrosequencing을 이용한 세균군집 조사 결과가 보다 효율적인 하천의 물관리 정책을 위해서 유용한 정보가 될 수 있을 것으로 기대한다.