• Food Science and Biotechnology
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• v.18 no.5
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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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• v.31 no.2
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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.

• Current Research on Agriculture and Life Sciences
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• v.30 no.2
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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.

• Korean Journal of Food Science and Technology
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• v.52 no.3
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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.

• Korean Journal of Food Science and Technology
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• v.19 no.5
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• pp.453-455
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• 1987

Swollen commercially canned grapes and peaches were collected to investigate the microorganisms involved in their spoilage. 6 of 52 grape and 19 of 23 peach samples were found to be spoiled by microorganisms. Yeasts were the only spoilage microorganisms of canned grapes with Saccharomyces cerevisiae as the leading spoilage yeast. Yeasts and bacteria were found from spoiled canned peaches. S. cerevisiae and Torulopsis stellata were the most important spoilage yeasts of canned peaches. Lactic acid bacteria, belonging to genera of Lactobacillus and Leuconostoc, were the most frequently found spoilage bacteria. Only one spore-forming bacterium, Bacillus licheniformis, was involved in the spoilage of canned peaches.

• Journal of Dairy Science and Biotechnology
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• v.35 no.3
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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.

• Journal of Microbiology and Biotechnology
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• v.23 no.12
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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.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.260-263
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• 2006

In this study, we investigated the antimicrobial effect of 14 different herbal petal extracts on various foodborne and food spoilage bacteria. Herbal petal extracts were prepared with 70% ethanol followed by sequential hexane, chloroform, ethyl acetate, n-butanol, and water fractionation. Antimicrobial activity was highest in the ethanol fraction from roselle (Hibiscus sabdariffa L.) petals as determined by the paper disc method. The roselle ethanol extract retarded the growth of food spoilage bacteria in kimbap (rice rolled in dried laver). Foodborne microorganisms (e.g. Bacillus cereus and Clostridium perfringens), on the other hand, were most efficiently inhibited by the ethyl acetate fraction of the roselle petal extract as determined by growth inhibition curves. Our study shows that roselle petals harbor antimicrobial activity against foodborne and food spoilage microorganisms. The critical ingredient is highly enriched in the ethyl acetate fraction of the extract.

• Food Science and Industry
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• v.52 no.3
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• pp.220-228
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• 2019

Rapid development of next-generation sequencing (NGS) technology is available to study microbes in genomic level. This NGS has been widely used in DNA/RNA sequencing for genome sequencing, metagenomics, and transcriptomics. The food microbiology area could be categorized into three groups. Food microbes including probiotics and food-borne pathogens are studied in genomic level using NGS for microbial genomics. While food fermentation or food spoilage are more complicated, their genomic study needs to be done with metagenomics using NGS for compositional analysis. Furthermore, because microbial response in food environments are also important to understand their roles in food fermentation or spoilage, pattern analysis of RNA expression in the specific food microbe is conducted using RNA-Seq. These microbial genomics, metagenomics, and transcriptomics for food fermentation and spoilage would extend our knowledge on effective utilization of fermenting bacteria for health promotion as well as efficient control of food-borne pathogens for food safety.

• Journal of Food Hygiene and Safety
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• v.28 no.4
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• pp.306-311
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• 2013

This study was conducted to investigate spoilage bacteria on organic and conventional fresh produce in Korea. Three samples (perilla leaf, cabbage, and romaine lettuce) of organic and conventional fresh produce were stored at $4^{\circ}C$ for 14 days and examined for spoilage bacteria on TSA. Isolated bacteria from organic and conventional fresh produces were identified using 16S rRNA sequencing method. Population of total aerobic bacteria on conventional perilla leaf, cabbage, and romaine lettuce were 7.59, 7.01, and $5.84{\log}_{10}CFU/g$, and populations of total aerobic bacteria were 6.72, 6.15, and $5.85{\log}_{10}CFU/g$, for organic perilla leaf, cabbage, and romaine lettuce, respectively. Major spoilage bacteria of organic and conventional fresh produces were similar however their levels were little different. For example, a major spoilage bacterium resulting the highest level on conventional perilla leaf was Stenotrophomonas maltophilia whereas that was Microbacterium sp. for organic produce. From these results, microflora or spoilage microorganism could be different depending on their cultivation types as conventional or organic produces and this information might be used for developing effective preservation method for different types of fresh produce.