사료자원에 서식하는 세균의 소화효소활성, 항생제내성 및 병원성에 관한 특성

이권정 ( Kwon Jung Yi ),조상섭 ( Sang Seop Cho ),김수기 ( Soo-ki Kim ) 한국가축위생학회 2017 韓國家畜衛生學會誌 Vol.40 No.2

Among different types of spoilage, microbial contamination can cause feed decomposition, which results in decreases in feed intake and productivity, infection, and breeding disorder. During the storage time, various microbes have a chance to inoculate with depreciation of feed and to infect the animals. We investigated bacteria that inhabit diverse feed ingredients and complete feed which have been stored for a few months. We isolated and identified 30 genera and 62 species of bacteria. Among these 62 species, 21 species were of non-pathogenic bacteria, 18 species were of pathogenic bacteria, 9 species were of opportunistic pathogens, and 14 species were of unknown bacteria. Pantoea allii and 24 species showed proteolytic enzyme activity. We also confirmed that 6 species including Pseudomonas psychrotolerans showed α-amylase activity, and 29 species including Burkholderia vietnamiensis showed cellulase activity. Microbacterium testaceum and 3 species showed resistance to Ampicillin, Kanamycin, Streptomycin, Gentamicin, Carbenicillin, and Erythromycin (50 μg/mL). Using mealworm larvae (Tenebrio molitor L.) as a model for pathogenicity, we confirmed that 8 species including Staphylococcus xylosus had pathogenicity for mealworm larvae. Especially, Enterobacter hormaechei, Staphylococcus xylosus, and Staphylococcus hominis were reported as being pathogenic for humans. This research suggests that hygienic management of animal feed is essential because beneficial and harmful bacteria can inhabit animal feed differently during storage and distribution.

고온 조건에서 사료 내 생균제의 생존성 및 오염미생물의 생장 억제 효과

김겸헌,이권정,이아란,장인환,송인근,김동운,김수기,Kim, Gyeom-Heon,Yi, Kwon-Jung,Lee, Ah-Ran,Jang, In-Hwan,Song, In-Geun,Kim, Dong-Woon,Kim, Soo-Ki 한국미생물학회 2014 미생물학회지 Vol.50 No.4

여름철의 고온으로의 온도 상승에 따른 사료빈 내의 생균제 L. plantarum, S. cerevisiae 및 B. subtilis의 생존성을 실험실의 가상 조건에서 분석하였다. 상온인 $25^{\circ}C$에서 멸균 사료와 비멸균 사료에 단일 혹은 혼합 균주 첨가 시 pH 변화와 생균제들의 생장을 상호 비교하였다. pH는 멸균 사료와 비멸균 사료 모두에서 4일째에 가장 감소한 것은 같았으나 비멸균 사료에서는 2일째까지는 상승하는 변화의 양상을 보여주었다. 멸균 여부 혹은 혼합 여부와 관계없이 S. cerevisiae와 B. subtilis의 생균수는 일정하게 유지되었지만 L. plantarum의 경우에는 그 수가 모두 줄어드는 것을 확인할 수 있었다. 따라서 3종의 혼합 생균제는 상호 길항작용은 없는 것으로 나타났다. 멸균 및 비멸균 사료에 생균제를 첨가한 후 $60^{\circ}C$의 고온 환경에서 사료의 pH 와 단일접종 생균제의 생존성을 조사하였다. 멸균 및 비멸균 사료 사이에 뚜렷한 pH의 변화는 관찰되지 않았으며 B. subtilis의 pH가 가장 낮게 관찰되었다. 고온 하에서 L. plantarum과 S. cerevisiae 균주는 생존할 수 없었으며, 내열성을 가진 B. subtilis 균주는 생존하면서 사료에 자연적으로 생존하는 오염세균의 증식을 억제하였다. 또 B. subtilis를 접종한 비멸균 사료에서 2일째부터 오염 곰팡이가 관찰되지 않았다. 따라서 내열성이 강한 B. subtilis 균주를 사용하면, 여름철 사료빈 내에 병원성 세균과 곰팡이의 오염을 억제할 수 있는 것으로 나타났다. The aim of this study was to investigate the effect of high temperature on the viability of probiotic organisms (Bacillus subtilis, Lactobacillus plantarum, and Saccharomyces cerevisiae) mixed with animal feed under controlled conditions by simulating a farm feed bin in the summer. Following inoculation of probiotics into the feed, the pH and probiotic viability were monitored during an 8-day incubation at room temperature. Sterile and non-sterile feeds displayed different patterns of pH changes, with increased pH in non-sterile feed at 2 days, but a pattern of decreasing pH at 4 days. The viabilities of S. cerevisiae and B. subtilis after mono/co-inoculation were maintained without substantial changes during the incubation, whereas L. plantarum viability tended to decline. In both non-sterile and sterile feeds, the probiotics were maintained or grew without any antagonistic effects. Probiotic viability was also tested upon a shift to high temperature ($60^{\circ}C$). There was no distinct change in pH between sterile and non-sterile feeds after the temperature shift. L. plantarum and S. cerevisiae could not survive at the high temperature, whereas B. subtilis displayed normal growth, and it inhibited the growth of contaminant microbes. Fungal growth was not observed in non-sterile feed 2 days after supplementation with B. subtilis. Therefore, heat resistant B. subtilis could be safely used in feed bins to inhibit microbial contamination, even at high temperatures. The prevention of elevated temperature in feed bins is necessary for the utilization of L. plantarum and S. cerevisiae during the summer season.

착유우용 배합사료의 부패과정 중 발생하는 저분자 유기화합물의 분석

김용탁 ( Yong Tak Kim ),이권정 ( Kwon Jung Yi ),김겸헌 ( Gyeom-heon Kim ),김동운 ( Dong Woon Kim ),김수기 ( Soo Ki Kim ),문형인 ( Hyung-in Moon ) 한국가축위생학회 2016 韓國家畜衛生學會誌 Vol.39 No.3

In this study, we analyzed for the changes of low organic compounds during 4 weeks incubation though inoculation of harmful microorganisms on commercial feed. Two percent of overnight cultures of Exiguobacterium acetylicum, Acinetobacter calcoaceticus, Aspergillus flavus and Fusarium graminearum were inoculated in feed, respectively. After adjusting moisture level to 50% for the promotion of feed spoilage, pH was decreased to 4.58∼5.03 and microorganism was ranged to 6∼10 log₁₀CFU/g. The compounds were compare between aflatoxin G1 producing feeds and aflatoxin G1 non-producing feeds. Aflatoxins G1 were detected by the immunoaffinity column clean-up method with HPLC-FLD, and were confirmed in samples incoulated by Aspergillus flavus and Acinetobacter calcoaceticus. Koiganal II, cy-clohexanol and butadien-one were detected from samples (the non-sterilized inoculated feed) by Aspergillus flavus and Acinetobacter calcoaceticus. Respectively as aflatoxin G1 pre-detected substance, Koiganal II, cyclohexanol and butadien-one may be useful substance for the pre-detection of aflatoxin G1.

Characteristics of Eggshell Powder as Carriers of Probiotics

Woo-Do Lee(이우도),Kai-Min Niu(우개민),Jeong-Min Lim(임정민),Kwon-Jung Yi(이권정),Bong-Joo Lee(이봉주),Kang-Woong Kim(김강웅),Kyoung-Duck Kim(김경덕),Sang-Woo Hur(허상우),Hyon-Sob Han(한현섭),Soo-Ki Kim(김수기) 한국생명과학회 2018 생명과학회지 Vol.28 No.1

계란 가공 부산물인 난각(ES: Eggshell)은 탄산칼슘 함량이 높아 사료에 첨가하여 칼슘원으로 이용되고 있다. 본 연구에서는 ES를 생균제의 부형제인 운반체로서 활용 가능성을 처음으로 시도하였다. L. plantarum을 대두박(SBM: Soybean meal), 난각조각(ESL: Eggshell powder with large particles), 난각미세분말(ESF: Eggshell powder with fine particles), 그리고 이들의 복합운반체인 SBM+ESL과 SBM+ESF에 생균제를 흡착시켜 그 부착상태를 주사전자현미경으로 확인하였다. 이 중 복합운반체인 SBM+ESF는 상온에서 4주 동안 pH 7~8을 유지하면서 L. plantarum의 가장 높은 생존율을 보였다. 본 연구에 사용한 모든 생균제들은 보존기간 동안 4℃에서는 높은 생존율을 보였다. 30℃에서는 유산균수는 크게 감소하였으나, B. licheniformis는 높은 생존율을 유지하였고 B. subtilis, B. amyloliquefaciens와 S. cerevisiae는 2 log10 (CFU/g)정도 감소하였다. 상기 연구결과는 사료의 칼슘원으로 이용되는 난각미세분말(ESF)을 대두박과 혼합하여 사용하면 B. licheniformis를 비롯한 일부 생균제의 생존성을 향상시켜 부형제(운반체)로도 사용할 수 있음을 밝혔다. Eggshell (ES) is a by-product of table eggs with high content of calcium carbonate which can be used as a calcium source in feed. In this study, we have first illuminated the potential application of ES as a novel carrier for probiotics. The carriers used in the study include a SBM (Soybean meal), ESL (Eggshell powder with large particles), ESF (Eggshell powder with fine particles), and the complex carriers (SBM+ESL, SBM+ESF). The structure of carriers absorbed by L. plantarum was confirmed by SEM image. Among these carriers, the complex carrier SBM+ESF showed the highest viability of L. plantarum with pH 7~8 during four weeks storage at room temperature. The SBM+ESF was further tested as a carrier for various probiotic strains at 4℃ or 30℃. All the probiotic strains showed high viability at 4℃ storage. However, a significant reduction of Lactobacillus cells was observed at 30℃ storage. B. lichenifomis maintained high viability whereas B. subtilis, B. amyloliquefaciens, and S. cerevisiae showed the reduction of 2 log10 (CFU/g). These results suggest that if the ESF as a calcium source in feed was mixed with SBM, it can be used as an effective complex carrier for improving the viability of some probiotics including B. licheniformis.

배합사료의 자연부패과정 중 발생하는 저분자 유기화합물의 동정 및 분석

유지민 ( Ji Min Yu ),김용탁 ( Yong Tak Kim ),이권정 ( Kwon Jung Yi ),김동운 ( Dong-woon Kim ),김수기 ( Soo-ki Kim ),문형인 ( Hyung In Moon ) 한국가축위생학회 2017 韓國家畜衛生學會誌 Vol.40 No.4

In this study, the changes of low molecular weight compounds during natural decay process for 4 weeks were analyzed. Natural corruptions were observed in the slate warehouse with summer humidity and temperature throughout the rainy season by using commercially available compound feeds. Koiganal was detected from 14 days of natural decay and corruption with chicken, pig, and Korean cattle feed. Ethyl palmitate, Ethyl pentadecanoate and, Methyl elaidatel were detected from chicken, pig, and Korean cattle feed. So, Koiganal can be useful for monitoring the degree of pollution of corruption of livestock feeds in advance.

도계 후 원료육의 저장기간 동안 가슴육의 품질 특성

황용준(Yong-Joon Hwang),박도희(Do-Hee Park),윤성호(Sung-Ho Yoon),김동준(Dong-Joon Kim),이원복(Won-Bok Lee),연제성(Jae-Sung Yeon),이권정(Kwon-Jung Yi),김수기(Soo-Ki Kim) 한국가금학회 2015 韓國家禽學會誌 Vol.42 No.4

본 연구는 도계 후 원료육의 저장기간에 따른 품질 특성을 조사하여 가공업소에서 반입되는 원료육에 대하여 현행 등급판정기준인 ‘도계 후 2일 이내의 원료육’의 사용이 적합한지 혹은 어느 정도 연장이 가능한지 여부를 판단하기 위하여 처음으로 수행하였다. 당일 도계한 원료육부터 도계 후 4일 경과된 원료육까지 총 40개의 샘플을 3℃의 냉장고에 냉장보관하여 부분육으로 발골 후 가슴육에 대하여 품질 특성을 연구하였다. 도계 후 2일 경과된 원료육과 3일 경과된 원료육을 비교 분석한 결과, 신선도는 각각 6.9와 7.0, 육색은 60.22와 60.51, 총균수는 4.20과 4.31 log10CFU/g, 지방산패도는 0.056과 0.071 mg MDA/kg, 전단력은 1.43과 1.59 kg/㎠, 가열감량은 17.24와 15.66%의 결과를 보였다. 신선도, 육색, 총균수, 지방산패도, 전단력 및 가열감량 모두 본 연구에서 도계 후 2일 경과된 원료육과 3일 경과된 원료육 간에 통계적 유의적인 차이가 없었다. 도계 후 4일 경과된 원료육은 신선도, 총균수, 전단력, 가열감량의 실험에서 2∼3일 경과된 원료육과 통계적 유의적인 차이가 없었으나, 지방산패도는 0.088 mg MDA/kg으로 유의적으로 높은 값을 보였다(P<0.05). 따라서 본 실험의 결과는 도계 후 3일 이내의 원료육도 사용이 가능하다는 것을 시사하였다. 등급판정 시 원료육의 사용 가능 시점을 도계 후 현행 2일에서 3일로 하루 연장할 수 있다면 닭고기 가공 및 유통업체는 원료육 사용 혹은 유통의 폭이 보다 넓어질 것으로 기대된다. This study was first conducted to investigate the effect of post-mortem storage time of chicken meat on the quality of chicken breast, and to determine whether the current grading rule that is ‘using the chicken meat within 2 day post-mortem (PM)’ is appropriate or not at meat processing plants. Different methods such as freshness, lightness (L<SUP>*</SUP>), total number of microbes, 2-thiobarbituric acid reactive substances (TBARS), shear force and cooking loss were performed. Forty samples of different PM time (0∼4 day) of chicken meat were stored in the refrigerator (3℃). As a result of comparing the chicken meat of 2 day and 3 day PM, torrymeter value was 6.9 and 7.0, respectively. The other values are also as follows: lightness (L<SUP>*</SUP>) 60.22 and 60.51, total number of microbes 4.20 and 4.31 log10CFU/g, TBARS value 0.056 and 0.071 mg MDA/kg, shear force 1.43 and 1.59 kg/㎠, and cooking loss 17.24 and 15.66%, respectively. As a result, these two groups were not significantly different (P<0.05). TBARS value of the chicken meat of 4 day PM was 0.088 mg MDA/kg which is significantly higher compared to 2∼3 day PM (P<0.05). Thus, the result of the study suggests that using the chicken meat within 3 day PM is also possible. If the grading rule that is ‘using the chicken meat within 2 day post-mortem (PM)’ is changed to 3 day PM, it will allow processing plants and distributors to more flexibly use or distribute chicken meat.