• Current Research on Agriculture and Life Sciences
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• 제30권2호
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• pp.105-109
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• 2012

Blacken spoilage is one of the common problems during the cold storage of dried persimmon in Korea. We collected the spoiled dried persimmon in the refrigerator and classified them to 4 types depending on their appearances. Furthermore we isolated blacken spoilage inducing bacteria from type D of dried persimmons. Among the isolates we identified the seven blacken spoilage inducing bacteria. They are Aeromonas hydrophila DP1, Cedecea davisae DP2, Ewingella americana DP3, Flavimonas oryzihabitans DP4, Providencia rettgeri DP5, Providencia rustigianii DP6 and Serratia plymuthica DP7. Strains were identified based on their morphological, cultural and physiological properties. We also found that Ewingella americana DP3, Flavimonas oryzihabitans DP4 were the major blacken spoilage inducing bacteria during dried persimmon storage.

• 한국식품과학회지
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• 제52권3호
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• pp.296-303
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• 2020

Hop-resistant lactic acid bacteria (LAB) are well-known, major beer-spoilage bacteria. The hop-gradient agar containing ethanol (c-HGA+E) method has been used to examine hop-resistance of beer-spoilage LAB. However, the selection of beer-spoilage bacteria by the c-HGA+E method is either too selective or too inclusive. Furthermore, it is accompanied by a complicated experimental procedure, high-cost and time. To overcome these disadvantages, the modified hop-gradient agar with ethanol (m-HGA+E) method was developed. The most remarkable modifications were the shape of the petri dish and the inoculation method for bacteria. The efficiency and validation of the m-HGA+E approach were proven by the formation of colonies at different hop concentrations in the bottom layer, co-culture with the bacteriocin producer and by PCR detection of hop-resistant genes. This study demonstrated that m-HGA+E is a rapid, economical, and easy method to monitor potential hop-resistant beer-spoilage LAB during the beer brewing process.

• 한국축산식품학회지
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• 제29권3호
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• pp.289-295
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• 2009

The aim of this research was to develop predictive models for the growth of spoilage bacteria (total viable cells, Pseudomonas spp., and lactic acid bacteria) on frankfurters and to estimate the shelf-life of frankfurters under aerobic conditions at various storage temperatures (5, 15, and $25^{\circ}C$). The primary models were determined using the Baranyi model equation. The secondary models for maximum specific growth rate and lag time as functions of temperature were developed by the polynomial model equation. During 21 d of storage under various temperature conditions, lactic acid bacteria showed the longest lag time and the slowest growth rate among spoilage bacteria. The growth patterns of total viable cells and Pseudomonas spp. were similar each other. These data suggest that Pseudomonas spp. might be the dominant spoilage bacteria on frankfurters. As storage temperature increased, the growth rate of spoilage bacteria also increased and the lag time decreased. Furthermore, the shelf-life of frankfurters decreased from 7.0 to 4.3 and 1.9 (d) under increased temperature conditions. These results indicate that the most significant factor for spoilage bacteria growth is storage temperature. The values of $B_f$, $A_f$, RMSE, and $R^2$ indicate that these models were reliable for identifying the point of microbiological hazard for spoilage bacteria in frankfurters.

• Food Science and Biotechnology
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• 제18권5호
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• pp.1243-1252
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• 2009

User-friendly software was developed to determine the shelf-life of perishable Korean seasoned side dishes in real time based on growth models of spoilage and pathogenic microorganisms. In the program algorithm, the primary spoilage and fastest-growing pathogenic organisms are selected according to the product characteristics, and their growth is simulated based on the previously monitored or recorded temperature history. To predict the growth of spoilage organisms with confidence limits, kinetic models for aerobic bacteria or molds/yeasts from published works are used. Growth models of pathogenic bacteria were obtained from the literature or derived with regression of their growth rate data estimated from established software packages. These models are also used to check whether the risk of pathogenic bacterial growth exceeds that of food spoilage organisms. Many example simulations showed that the shelf-lives of the examined foods are predominantly limited by the growth of spoilage organism rather than by pathogenic bacterial growth.

• 한국식품과학회지
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• 제19권5호
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• pp.453-455
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• 1987

팽창된 깐포도 및 복숭아 통조림을 시중에서 수거하여 부패현상을 검사한 결과 pH가 비교적 낮은 깐포도 통조림은 52개의 팽창관중 6개가 또 pH가 비교적 높은 복숭아 통조림은 23개 중 19개가 미생물에 의해 부패되었음을 알았다. 깐포도 통조림의 주요 부패 미생물은 Saccharomyces cerevisiae였고, 복숭아 통조림의 주요 부패 미생물은 S. cerevisiae 및 Torulopsis stellata로 밝혀졌다. 기타 Lactobacillus 및 Leuconostoc속의 젖산균도 흔히 발견되었으며, 포자형성세균으로는 Bacillus licheniformis가 한 개의 통조림에서 발견되었다.

• 한국식품위생안전성학회지
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• 제28권4호
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• pp.306-311
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• 2013

본 연구는 부패미생물의 종류와 차이를 알아보기 위해 유기농산물과 일반농산물(깻잎, 양배추, 상추)을 구입하여 $4^{\circ}C$에 14일 저장한 후 일반목적배지를 사용하여 미생물을 분리 및 16S rRNA sequencing방법을 이용하여 동정하였다. 유기농산물 깻잎, 양배추, 상추의 총균수는 $5-7{\log}_{10}CFU/g$ 수준이었고, 일반농산물의 총균수는 $5-8{\log}_{10}CFU/g$ 수준이었다. 유기농산물보다는 일반농산물이 총균수를 더 많이 내재하고 있으나 유의적인 차이는 나타나지 않았다(p > 0.05). 유기농산물 깻잎에서 발견된 주요 균은 Microbacterium sp.이었으며, 일반농산물 깻잎에서 발견된 주요균은 Stenotrophomonas maltophilia이었다. 또한, 유기농산물에서 부패를 일으킬 수 있는 균인 Klebsiella pneumonia가 발견되었으며, 일반농산물보다 유기농산물에서 발견된 균의 종류가 더 많은 것을 확인할 수 있었다. 이에 본 연구 결과는 부패미생물에 대한 이해를 높이고 농산물의 신선도 및 유통기한을 늘리기 위한 새로운 살균소독제 및 부패 억제제를 개발하는데 좋은 기초자료로 사용될 수 있을 것으로 사료된다.

• Journal of Dairy Science and Biotechnology
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• 제31권2호
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• pp.179-186
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• 2013

Pseudomonas spp. are Gram-negative psychrophilic bacteria, which can proliferate at refrigeration temperature. The bacteria produce heat-stable enzymes that can degrade fat and protein in foods. Hence, Pseudomonas spp. are related to the spoilage of milk, dairy products, and meat products under cold storage, causing economic loss. In the food industry, various methods have been used to remove bacteria including Pseudomonas spp. in food-related conditions, but they can be resistant to antimicrobials and sanitizers because they form biofilms regulated by quorum sensing (cell density-dependent cell-to-cell signaling). Since Pseudomonas cells in biofilms can cross-contaminate foods resulting in food spoilage and the survival of food-borne pathogens in food-related conditions, efficient decontamination technology and microbiological criteria should be established to reduce the occurrence of food spoilage by Pseudomonas spp.

• 한국식품위생안전성학회지
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• 제13권4호
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• pp.383-387
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• 1998

본 연구는 포장두부에서 부패 세균을 분리.동정하고, 부패균주의 생육 특성과 내열성을 조사하여 두부 제조공정의 위생관리를 위한 기초 자료로 제시할 목적으로 수행되었다. 포장두부의 부패에 관여하는 세균을 분리하여 Vitek system을 이용하여 동정한 결과, Strain No. T1은 Enterobacter amnigenus일 확률이 92%, Strain No T2는 Flavobacterium indologenes일 확률이 96%이었다. 이들 균주는 $35^{\circ}C$와 pH6.5일 때 가장 생육이 왕성하였다. Enterobacter amnigenus T1의 내열성을 검토한 결과, $60^{\circ}C$에서 2분 처리하였을 경우 초기보다 56.3%, $70^{\circ}C$에서는 37.8%, $80^{\circ}C$에서는 34.0%, $90^{\circ}C$에서 처리했을 때는 22.2%가 잔존하였고, Flavobacterium indologenes T2 경우는 $60^{\circ}C$에서 2분 동안 처리하였을 때 74.8%, $70^{\circ}C$에서는 65.7%, $80^{\circ}C$에서는 37.3%, $90^{\circ}C$에서 처리했을 경우는 9.3%가 잔존하였다.

• 한국축산식품학회지
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• 제37권4호
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• pp.535-541
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• 2017

This study investigated the psychrotrophic bacteria isolated from chicken meat to characterize their microbial composition during refrigerated storage. The bacterial community was identified by the Illumina MiSeq method based on bacterial DNA extracted from spoiled chicken meat. Molecular identification of the isolated psychrotrophic bacteria was carried out using 16S rDNA sequencing and their putrefactive potential was investigated by the growth at low temperature as well as their proteolytic activities in chicken meat. From the Illumina sequencing, a total of 187,671 reads were obtained from 12 chicken samples. Regardless of the type of chicken meat (i.e., whole meat and chicken breast) and storage temperatures ($4^{\circ}C$ and $10^{\circ}C$), Pseudomonas weihenstephanensis and Pseudomonas congelans were the most prominent bacterial species. Serratia spp. and Acinetobacter spp. were prominent in chicken breast and whole chicken meat, respectively. The 118 isolated strains of psychrotrophic bacteria comprised Pseudomonas spp. (58.48%), Serratia spp. (10.17%), and Morganella spp. (6.78%). All isolates grew well at $10^{\circ}C$ and they induced different proteolytic activities depending on the species and strains. Parallel analysis of the next generation sequencing and culture dependent approach provides in-depth information on the biodiversity of the spoilage microbiota in chicken meat. Further study is needed to develop better preservation methods against these spoilage bacteria.

• Asian-Australasian Journal of Animal Sciences
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• 제23권7호
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• pp.960-964
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• 2010

Water-cooked salted ducks were tray-packaged and stored under refrigeration ($4{\pm}1^{\circ}C$) in order to evaluate the quality changes during storage. pH, total volatile basic nitrogen (TVB-N), sensory and microbiological analysis were determined at 0, 2, 4, 6, 8, 9 and 10 days of storage. pH value and TVB-N (mg N/100 g) varied from $6.47{\pm}0.16$ to $6.69{\pm}0.10$ and from $5.90{\pm}0.93$ to $13.42{\pm}2.46$, respectively. Sensory results indicated that ducks were unacceptable at the 10th day of storage. The predominant spoilage bacteria at the end of the shelf-life were Brochothrix thermosphacta, lactic acid bacteria (LAB) and minor components were Enterobacteriaceae, members of Micrococci, yeasts and moulds. Pseudomonads were also detected. Both total bacteria and the various spoilage ones, overall, increased from the initial sampling to the final day.