• 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.

• Journal of Industrial Technology
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• v.28 no.A
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• pp.141-147
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• 2008

Several contaminated bacteria such as Lactobacillus brevis and Pediococcus damnosus in beer production cause beer spoilage by producing off flavours and turbidity. Detection of these organisms is complicated by the strict anaerobic conditions and lengthy incubation times required for their cultivation, consequently there is a need for more rapid detection methods. Recently, two contaminated strains were isolated from vessel of beer production and identified as Lactobacillus species by API kit identificaton as well as 16S-23S ITS sequencing analyses. Two isolated strains were named as Lactobacillus sp. HLA1 and Lactobacillus HLB2, respectively. A polymerase chain reaction (PCR) method was developed for the rapid and specific detection of Lactobacillus sp.. Two sets of primer pairs (HLA1-F/HLA1-R and HLB2-F/HLB2-R) were designed for the amplification of a 1576 base pair (bp) fragment of the HLA1 16S-23S rRNA gene and 1888 bp fragement of the HLB2 16S-23S rRNA. Amplified PCR products were highly specific to detect corresponding bacteria when other contaminated strains were used as PCR templates. However, detection of both strains were limited when $100{\mu}{\ell}$ of cultured samples were mixed with $100m{\ell}$ of beer sample in arbitrary manner. The sensitivity of the assay still needs to be improved for direct detection of the small amounts of bacteria present in beer.

• Microbiology and Biotechnology Letters
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• v.48 no.3
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• pp.322-327
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• 2020

Abortive infection systems (Abi) are phage resistance systems that can be prophage-encoded. Here, two genes encoding an Abi system were identified on a prophage sequence contained by the chromosome of the Levilactobacillus brevis strain UCCLBBS124. This Abi system is similar to the two-component AbiL system encoded by Lactococcus lactis biovar. diacetylactis LD10-1. The UCCLBBS124 prophage-derived Abi system (designated here as AbiL₁₂₄) was shown to exhibit specific activity against phages infecting L. brevis and L. lactis strains. Expression of the AbiL₁₂₄ system was shown to cause reduction in the efficiency of plaquing and cell lysis delay for phages of both species.

• Journal of Dairy Science and Biotechnology
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• v.38 no.4
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• pp.230-236
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• 2020

Heat treatment is a fundamental processing technology in the dairy industry. The main purpose of heat treatment is to destroy pathogenic and spoilage promoting microorganisms to ensure milk safety and shelf life. Despite the development of alternative technologies, such as high-pressure processing and pulse field technology for microbial destruction, heat treatment is widely used in the dairy industry and in other food processes to destroy microorganisms. Heat treatment has contributed greatly to the success of food preservation since Pasteur's early discovery that heat treatment of wine and beer could prevent their deterioration, and since the introduction of milk pasteurization in the 1890s. In Korea, food labeling standards do not stratify heat treatments into low temperature, high temperature, and ultra-high temperature methods. Most milk is produced in Korea by pasteurization, with extended shelf life (ESL : 125--140℃ / 1-10 s). Classification based on temperature (i.e. low, high, and ultra-high), is meaningless.

• Food Science of Animal Resources
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• v.27 no.2
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• pp.185-189
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• 2007

Animals must be inspected prior to and after slaughter to make certain they are free of diseases and unacceptable defects. Since meats are potentially hazardous foods, they should not be accept if there are any signs of contamination, temperature abuse, or spoilage. This survey was aimed to monitor the current situation of country-of-origin labels and sanitation for the meat markets in Seoul, Korea. The markets were divided into groups as to 25 territories in Seoul and the size of markets (large size, medium size, and small size). In terms of size distribution, small butcher shops occupied the highest percentage. On the itemized suitability test of unpacked and packed beer in Seoul, most butcher shops showed good evaluation. However, labels indicating the grade, storage and cooking instruction for unpacked beef were not properly posted on the products. The results of monitoring sanitation conditions for butcher shops in Seoul showed relatively low suitability. Especially, there were serious lack of knowledge about wearing the sanitation clothings, caps, and shoes. The problem with food safety is so complicated that producers, consumers, merchandisers, the press, the government and the scholar should try to solve the problems altogether. Also, it is important to educate and provide them with correct understanding and information for food hygiene and safety.