• 한국포장학회지
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• 제17권2호
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• pp.33-37
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• 2011

변패성 식품의 하나로서 양념돼지불고기의 미생물적 저장수명을 실시간적으로 제어하는 방법으로서 포장 내 $CO_2$ 농도의 측정을 이용하는 방법을 고안하고 동적온도조건에서 그 적용가능성을 확인하였다. 식품으로부터의 $CO_2$ 생산 속도 혹은 포장 내 $CO_2$ 농도변화가 증가하기 시작하는 시점이 미생물적 한계품질에 해당되었고, 이를 저장수명의 결정의 지표로 사용할 수 있는 것으로 나타났다. 이는 또 특정 $CO_2$ 농도에 도달되는 시점, 즉 $CO_2$ 농도변화의 유도기와도 일치하였다. 제안된 logic은 $CO_2$ 농도를 실시간으로 측정하고 무선으로 데이터를 전송할 수 있는 sensor 시스템에 의하여 가능성이 확인되었다.

• 한국식품과학회지
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• 제50권1호
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• pp.55-60
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• 2018

과거 전통방식으로 제조되는 4가지 상업용 시판누룩들을 파이로시퀀싱 방법을 이용하여 미생물군집을 확인하였다. 누룩시료의 진균류 총 유효 sequencing read수는 14,800이였으며 후속 quality trimming, denoising와 chimera removal와 같은 작업을 통해 얻은 평균 sequence read의 수는 3,494이였다. 진균류의 phylum 수준에서 SH, JJ, SS 시료에서는 자낭균류가 우세한 것으로 확인되었으나 SJ는 접합균류가 우세하였다. 발효력과 관계가 있는 것으로 알려진 Saccharomycopsis속 효모분포는 제조과정에서 상대적으로 발효시간이 길었던 SH와 SS의 경우에서 더 많았다. 세균류의 파이로시퀀싱결과 유효 sequencing read수는 31,485이였으며 평균 sequence read는 7,871이였다. 세균의 phylum 수준에서는 모든 시료에서 Firmicutes문이 우세한 것으로 분석되었다. SH의 경우 주로 Lactobacillus속, Leuconostoc속, 기타 Pediococcus속과 이를 포함하는 Lactobacillales목과 Leuconostocaceae과 등 젖산균들이 우세균주로 분포하였다. JJ와 SJ의 경우, 각각 Staphylococcus속과 Bacillus속이 우세균으로 나타났다.

• 한국환경과학회지
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• 제30권8호
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• pp.703-708
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• 2021

To improve the environmental management and resources, in this study, we aimed to investigate the effect of adding oyster shell powder to Hanwoo manure on its characteristics and microbial composition during the storage period. Additives were deposited on top of the manure surface at the rate of 0, 0.5, and 1% of oyster shell powder per 200 g of Hanwoo manure in a plastic container with three replicates; however, untreated manure litter served as the control. Manure characteristics (dry matter, organic matter and crude ash) and microbial composition (lactic acid bacteria, yeast, Bacillus subtilis, Salmonella, and E.coli) were evaluated at day 0, 2, 4, and 8. Manure characteristics exhibited an effect on dry matter, organic matter, and crude ash at day 2 and 8 (p<0.05), and not for day 0 and 4 (p>0.05). With the exception of yeast content at day 4 of storage, lactic acid bacteria, yeast, Bacillus subtilis, Salmonella, and E.coli exhibited no significant differences in all conditions during the storage period. Conclusively, addition of 1% oyster shell powder to Hanwoo manure resulted in slightly better manure characteristics; however, its microbial composition remained unchanged.

• Journal of Electrochemical Science and Technology
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• 제13권2호
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• pp.308-320
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• 2022

The high internal resistance (R_int) that develops across the sediment microbial fuel cells (SMFC) limits their power production (~4/10 mW m^-2) that can be recovered from an initial oil-contaminated sediment (OCS). In the anolyte, R_int is related to poor biodegradation activity, quality and quantity of contaminant content in the sediment and anode material. While on the catholyte, R_int depends on the properties of the catholyte, the oxygen reduction reaction (ORR), and the cathode material. In this work, the main factors limiting the power output of the SMFC have been minimized. The power output of the SMFC was increased (47 times from its initial value, ~4 mW m^-2) minimizing the SMFC R_int (28 times from its initial value, 5000 ohms), following the main modifications. Anolyte: the initial OCS was amended with several amounts of gasoline and kerosene. The best anaerobic microbial activity of indigenous populations was better adapted (without more culture media) to 3 g of kerosene. Catholyte: ORR was catalyzed in birnessite/carbon fabric (CF)-cathode at pH 2, 0.8M Na₂SO₄. At the class level, the main microbial groups (Gammaproteobacteria, Coriobacteriia, Actinobacteria, Alphaproteobacteria) with electroactive members were found at C-anode and were associated with the high-power densities obtained. Gasoline is more difficult to biodegrade than kerosene. However, in both cases, SMFC biodegradation activity and power output are increased when ORR is performed on birnessite/CF in 0.8 M Na₂SO₄ at pH 2. The work discussed here can focus on bioremediation (in heavy OCS) or energy production in future work.

• Journal of Animal Science and Technology
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• 제65권1호
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• pp.96-112
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• 2023

Rye (Secale cereale L.) is a valuable annual forage crop in Korea but there is limited information about the impact of chemical and biological additives on fermentation characteristics of the crop. This experiment was conducted to investigate fermentation dynamics of wilted forage rye treated with the following six additives; control (no additive), sodium diacetate applied at 3 g/kg wilted forage weight (SDA3), 6 g/kg wilted forage weight (SDA6), inoculations (10⁶ CFU/g wilted forage) of Lactobacillus plantarum (LP), L. buchneri (LB), or LP+LB. The ensiled rye sampled at 1, 2, 3, 5, 10, 20, 30, and 45 days indicated that the acidification occurred fast within five days of storage than the rest of the storage period. The microbial inoculants decline the pH of ensiled forage, more rapidly than the control or SDA treated, which accompanied by the decrease of water-soluble carbohydrates and increase of lactic acid. Compared with the control silage, all treatments suppressed ammonia-nitrogen formation below to 35 g/kg DM throughout the sampling period. Suppression of total microbial counting occurred in SDA6, LP, and LP + LB. The lactic acid production rates were generally higher in microbial inoculation treatments. Acetic acid concentration was lowest in the LP-treated silage and highest in the SDA- and LB-treated silages. The in vitro dry matter (DM) digestibility and total digestible nutrients were the highest in the silage treated with SDA (6 g/kg) at day 45 of ensiling. Based on lower ammonia-nitrogen concentrations and higher feed value, ensiling forage rye treated with SDA at 6 g/kg is promising through enhanced silage quality.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제4권2호
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• pp.86-94
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• 2023

Climate change is more rapid in the Arctic than elsewhere in the world, and increased precipitation and warming are expected cause changes in biogeochemical processes due to altered microbial communities and activities. It is crucial to investigate microbial responses to climate change to understand changes in carbon and nitrogen dynamics. We investigated the effects of increased temperature and precipitation on microbial biomass and community structure in dry tundra using two depths of soil samples (organic and mineral layers) under four treatments (control, warming, increased precipitation, and warming with increased precipitation) during the growing season (June-September) in Cambridge Bay, Canada (69°N, 105°W). A phospholipid fatty acid (PLFA) analysis method was applied to detect active microorganisms and distinguish major functional groups (e.g., fungi and bacteria) with different roles in organic matter decomposition. The soil layers featured different biomass and community structure; ratios of fungal/bacterial and gram-positive/-negative bacteria were higher in the mineral layer, possibly connected to low substrate quality. Increased temperature and precipitation had no effect in either layer, possibly due to the relatively short treatment period (seven years) or the ecosystem type. Mostly, sampling times did not affect PLFAs in the organic layer, but June mineral soil samples showed higher contents of total PLFAs and PLFA biomarkers for bacteria and fungi than those in other months. Despite the lack of response found in this investigation, long-term monitoring of these communities should be maintained because of the slow response times of vegetation and other parameters in high-Arctic ecosystems.

• 한국식품과학회지
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• 제35권6호
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• pp.1110-1116
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• 2003

신선 편의가공 양파제품의 적정 포장방법을 탐색하고자 polyolefin계 유연 필름(LDPE, PP)을 이용한 수동 MAP, 20% $O_2/10%\;CO_2/70%\;N_2$ 혼합기체 또는 에틸렌 흡수제를 첨가한 능동 MAP, LDPE 필름으로 감압 포장한 MVP 등의 적용 가능성을 조사하였다. 박피 양파의 포장방법을 달리하여 $10^{\circ}C$에서 28일간 저장하면서 이화학적, 미생물, 관능적 품질변화를 측정하여 개별 품질인자에 대한 포장처리 효과를 검토하였다. 전체적으로 포장방법에 따른 저장중 박피 양파의 표면색, 중량 감소, 미생물 증식은 차이를 분명하게 구분하기 어려웠으나, 외관품질과 부패율 측면에서는 일정한 차이를 식별할 수 있었다. 결과적으로 기체투과성 LDPE 필름에 일정수준의 진공을 적용하여 밀봉 포장한 MVP가 다른 포장구에 비해 상대적으로 박피 양파의 저장품질을 우수하게 유지하는 것으로 확인되었다.

• 한국축산식품학회지
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• 제38권3호
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• pp.487-497
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• 2018

Controlling of microorganisms in the industrial process is important for production and distribution of hatching and table eggs. In the previous study, we reported that chlorine dioxide ($ClO_2$) gas of a proper concentration and humidity can significantly reduce the load of Salmonella spp. on eggshells. In this study, we compared microbial reduction efficacy on egg's surface using hatching eggs and table eggs, internal quality of table eggs, and hatchability after both the conventional method (washing and UV expose, fumigation with formalin) and $ClO_2$ gas disinfection. Application of 40 ppm $ClO_2$ gas to the table and hatching eggs, respectively, reduced the aerobic plate count (APC) with no statistical difference compared with the conventional methods. Additionally, we didn't observed that any significant difference in albumin height, Haugh unit (HU), and yolk color, this result confirms that 40 ppm $ClO_2$ had no effect on the internal quality of the table eggs, when comparing with the UV treatment method. The hatchability of hatching eggs was not statistical different between formaldehyde fumigation and 80 ppm $ClO_2$ gas treatment, though the value was decreased at high concentration of 160 ppm $ClO_2$ gas. From these results, we recommend that $ClO_2$ gas can be used as a safe disinfectant to effectively control egg surface microorganisms without affecting egg quality.

• 한국축산식품학회지
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• 제39권1호
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• pp.139-150
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• 2019

This study aimed to determine the suitable point of sale and consumption of different quality grade (QG) Hanwoo short loin during aging period, based on physicochemical, sensory, and microbiological quality. Short loins obtained from the carcasses of 13 Hanwoo steers and 2 bulls with 5 different QGs (1++, 1+, 1, 2, and 3) were analyzed over 28 d. QG and aging time had significant effect on water holding capacity, color, shear force, total volatile basic nitrogen (TVBN) content, and sensory traits. Higher QG groups generally exhibited a lower shear force, nucleotide content, and water holding capacity, and higher $L^*$, $a^*$, and $b^*$ values. Acceptable tenderness (shear force <5.4 kg) in QG 1++, 1+, 1, and 2 was achieved on days 7, 14, 16, and 18, respectively, and QG 3 showed a shear force of 6.8 kg, even after 28 d. Regardless of QG, TVBN content below threshold levels (20-30 mg%) was observed throughout the 28 d aging period, while total plate counts above 7 Log CFU/g were seen at 21 d. In conclusion, it is recommended that Hanwoo beef with QG 1++, 1+, and intermediate QG (1 and 2) should be sold or consumed between 7 and 21, 14 and 21, 16 and 21 d, respectively. Beef with QG 3 should be sold or consumed within 21 d, based on microbial growth, even though it has not achieved desirable tenderness. For this reason, an additional tenderizing process is recommended before this beef is ready for consumption.

• Animal Bioscience
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• 제36권12호
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• pp.1842-1852
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• 2023

Objective: Hairy vetch is considered to improve the nutritional value of corn because of its high protein and mineral levels. To better understand the mechanism underlying hairy vetch regulated whole-plant corn silage fermentation, this experiment investigated the fermentation quality and bacterial community of whole-plant corn and hairy vetch mixture. Methods: Whole-plant corn and hairy vetch were mixed at ratios of 10:0 (Mix 10:0), 8:2 (Mix 8:2), 6:4 (Mix 6:4), 4:6 (Mix 4:6), 2:8 (Mix 2:8), and 0:10 (Mix 0:10) on a fresh weight basis. After ensiling 60 days, samples were collected to examine the fermentation dynamics, ensiling characteristics, and bacterial communities. Results: Mix 0:10, Mix 2:8, and Mix 4:6 showed poor fermentation characteristics. Mix 8:2 and Mix 6:4 silages showed high quality, based on the low pH, acetic acid, and ammonia nitrogen levels and the high lactic acid, crude protein, and crude fat contents. The bacterial diversity was affected by the mixing ratio of the two forage species. The genus Lactobacillus dominated the bacterial community in Mix 10:0 silage, whereas with the addition of hairy vetch, the relative abundance of unclassified-Enterobacter increased from 7.67% to 41.84%, and the abundance of Lactobacillus decreased from 50.66% to 13.76%. Conclusion: The silage quality of whole-plant corn can be improved with inclusion levels of hairy vetch from 20% to 40%.