• 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.

• Journal of Dairy Science and Biotechnology
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• 제35권3호
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• pp.152-161
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• 2017

Cheese is an excellent substrate for yeast and mold growth. These organisms can cause cheese spoilage, resulting in significant food wastage and economic losses. In the context of cheese spoilage, the presence and effects of spoilage or pathogenic bacteria are well documented. In contrast, although yeasts and molds are responsible for much dairy food wastage, only a few studies have examined the diversity of spoilage fungi. This article reviews the spoilage yeasts and molds affecting cheeses in various countries. The diversity and number of fungi present were found to depend on the type of cheese. Important fungi growing on cheese include Candida spp., Galactomyces spp., Debaryomyces spp., Yarrowia spp., Penicillium spp., Aspergillus spp., Cladosporium spp., Geotrichum spp., Mucor spp., and Trichoderma spp.. In addition, several mold spoilage species, such as Aspergillus spp. and Penicillium spp., are able to produce mycotoxins, which may also be toxic to humans. There are many ways to eliminate or reduce toxin levels in foods and feeds. However, the best way to avoid mycotoxins in cheese is to prevent mold contamination since there are limitations to mold degradation or detoxifications in cheese. Chemical preservatives, natural products, and modified atmosphere packaging have been used to prevent or delay mold spoilage and improve product shelf life and food safety.

• 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.

• 한국환경농학회지
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• 제37권3호
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• pp.221-228
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• 2018

BACKGROUND: Spoilage fungi can reduce the shelf life of fresh fruits and cause economic losses by lowering quality. Especially, mulberry fruits have high sensitivity to fungal attack due to their high water content (> 70%) and soft texture. In addition, the surface of these fruits is prone to damage during harvesting and postharvest handling. However, any study on postharvest spoilage fungi in mulberry fruit has not been reported in Korea. This study aimed to examine the spoilage fungi occurring in mulberry fruits during storage after harvest. METHODS AND RESULTS: In this study, we isolated postharvest spoilage fungi from mulberry fruits stored in refrigerator (fresh fruits) and deep-freezer (frozen fruits) and identified them. In the phylogenetic analysis based on comparisons of the ITS rDNA sequences, the 18 spoilage fungi isolated from mulberry fruits and the 25 reference sequences were largely divided into seven groups that were subsequently verified by high bootstrap analysis of 73 to 100. Alternaria spp. including A. alternate and A. tenuissima, were the most frequently isolated fungi among the spoilage isolates: its occurrence was the highest among the 18 isolates (38.9%). CONCLUSION: The findings of this study will be helpful for increasing the shelf life of mulberry fruits through the application of appropriate control measures against infection by spoilage fungi during 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.

• 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.

• 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.

• 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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• 제19권1호
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• pp.25-30
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• 2004

숙주나물과 콩나물은 blanching후 변질 속도가 크게 차이가 나는 바 이들이 Bacillus subtilis, Bacillus cereus, Pseudomonas fluorescens, Listeria monocytogenes등 4종의 부패성 및 식중독 미생물의 증식에 미치는 영향을 조사하였다. 숙주나물과 콩나물의 조리과정 중 blanching조건이 달라 각각의 조건에서 두 시료 모두 blanching하여 생균수를 측정한 결과 blanching 한 후 미생물 수는 저장시간에 따라 증가하나 그 차이가 없었다. 최소배지에 숙주나물과 콩나물 농축물 및 부패성 미생물을 접종한 후 생균수를 측정한 결과 숙주나물에 접종한 모든 균들의 초기 균수가 높았으나 24시간 이후 비슷한 증식양상을 나타내었다. 그러나 숙주나물과 콩나물의 여액을 배지로 사용하여 실험한 결과 미생물의 증식 양상은 균주 마다 다른 것으로 나타났다. 저장기간 동안 색도를 측정한 결과 숙주나물의 경우 24시간에는 색차가 거의 없다가 48시간 이후 현저한 차이를 보였고, 콩나물의 경우 24시간에 다른 계통의 색으로 변하다가 48시간 이후 현저하게 많은 차이를 보여 다른 양상을 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제23권12호
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• pp.1717-1725
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• 2013

Traditional soybean paste from Shandong Liangshan and Tianyuan Jiangyuan commercial soybean paste were chosen for analysis and comparison of their bacterial and fungal dynamics using denaturing gel gradient electrophoresis and 16S rRNA gene clone libraries. The bacterial diversity results showed that more than 20 types of bacteria were present in traditional Shandong soybean paste during its fermentation process, whereas only six types of bacteria were present in the commercial soybean paste. The predominant bacteria in the Shandong soybean paste were most closely related to Leuconostoc spp., an uncultured bacterium, Lactococcus lactis, Bacillus licheniformis, Bacillus spp., and Citrobacter freundii. The predominant bacteria in the Tianyuan Jiangyuan soybean paste were most closely related to an uncultured bacterium, Bacillus licheniformis, and an uncultured Leuconostoc spp. The fungal diversity results showed that 10 types of fungi were present in the Shandong soybean paste during the fermentation process, with the predominant fungi being most closely related to Geotrichum spp., an uncultured fungal clone, Aspergillus oryzae, and yeast species. The predominant fungus in the commercial soybean paste was Aspergillus oryzae.