• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.165-168
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• 2016

Surface protein internalin (InlA) is a major virulence factor of the food-borne pathogen L. monocytogenes. It plays an important role in bacteria crossing the host's barrier by specific interaction with the cell adhesion molecule E-cadherin. Study of this protein will help to find better ways to prevent listeriosis. In this study, a monoclonal antibody against InlA was used to detect InlA. The reaction was label-free and monitored in real time with an oblique-incidence reflectivity-difference (OI-RD) technique. The kinetic constants k_on and k_off and the equilibrium dissociation constant K_d for this reaction were also obtained. These parameters indicate that the antibody is capable of detecting InlA. Additionally, the results also demonstrate the feasibility of using OI-RD for proteomics research and bacteria detection.

• Korean Journal of Veterinary Research
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• v.31 no.3
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• pp.279-284
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• 1991

To investigate the epidemiological aspects of listeriosis, serotypes of L monocytogenes and antimicrobial susceptibilities of Listeria spp isolated from chicken carcases and chicken slaughter house environmental specimens were determined. Of 28 L monocytogenes strains, 12 strains(42.9%) were serotype 4, and the remaining 16 strains were untypable. Peak distributions of minimum inhibitory concentration$({\mu}g/ml)$ of the isolates were $0.78{\mu}g/ml$ for ampicillin, $0.39{\mu}g/ml$ for erythromycin and penicillin G, $1.56{\mu}g/ml$ for tetracycline and $6.25{\mu}g/ml$ or $12.5{\mu}g/ml$ for chloramphenicol, and $3.13{\mu}g/ml$ to > $100{\mu}g/ml$ for kanamycin and neomycin. Most of 214 isolates were sensitive to ampicillin and erythromycin, but 20. 1~78. 0% of the strains were resistant to tetracycline, kanamycin, penicillin-G and neomycin. Single or double drug resistance were observed in 75.8% of the resistant strains. The most common resistance patterns were Nm P-G(37.4%) in double pattern and P-G(23.7%) in single pattern.

• Korean Journal of Veterinary Research
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• v.31 no.3
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• pp.271-277
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• 1991

To investigate the epidemiological trait of listeriosis, Listeria spp were isolated from poultry meat, products and environmental specimens in chicken slaughterhouse. Also determined were isolation rates by the different enrichment procedures, the biochemical properties of isolates. In a total of 307 samples including poultry meat, liver, feathers, feces, chiller water, scalding water overflow and slaughterhouse floor, Listeria spp were isolated predominantly from scalding water overflow (90.0%), body skin before washing (66.7%), liver (20.0%) and feathers(15.0%) However, few Listeria spp were isolated from body skin after washing and feces. The higher isolation rates were obtained in the secondary enrichment procedure (7.2%) than in the primary enrichment (3.9%); after stored the secondary enrichment cultures for 2 weeks at $4^{\circ}C$, Listeria spp were present in 9.8%. The majority of the isolated Listeria spp were identical to those of the standards strains in biochemical and cultural properties. Overall, Listeria spp were present in 13.4% of the specimens tested, and were in order of prevalence of L innocua(11.1%), L monocytogenes(3.3%), L grayi(0.7%) and L murrayi(0.3%).

• Food Science of Animal Resources
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• v.35 no.5
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• pp.669-673
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• 2015

The aims of this study were to investigate the occurrence of Listeria species in turkey meats and to check the antimicrobial susceptibility of the isolated strains. Hundred and fifteen raw turkey meat samples were randomly collected from the supermarkets, butchers and restaurants. Strain isolation and identification were made according to the ISO11290-1 method. Antimicrobial susceptibility was determined by the standard disc diffusion method. A total of 47 Listeria spp. were isolated from 115 (40.9%) raw turkey meat samples. The isolates were distributed between L. monocytogenes (25.53%), L. innocua (34.04%), L. grayi (31.91%) and L. welshimeri (8.51%). A total of 55.3 % of Listeria spp. isolates were multi-resistant to at least 3 of the antimicrobial agent tested. The level of multi-resistance was higher in L. monocytogenes strains (66.7%) than in L. innocua (62.5%) and L. grayi (53.3%). Listeria spp. isolates were highly resistant to ampicillin, cephalothin, penicillin, meticillin, oxacillin, and trimethoprime-sulfamethoxazole. The isolates particularly L. monocytogenes are increasingly resistant to one or more antibiotics and may represent a potential risk for public health because these antibiotics are common used in treatment of listeriosis. The correct and controlled use of antibiotics in veterinary medicine is important to the emergence of resistant strains.

• Preventive Nutrition and Food Science
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• v.3 no.2
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• pp.157-162
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• 1998

As a part of investigation for listeriosis, we attmepted iolationof Listeria spp. from commerical frozen and refrigerated foods at the supermarket level. Seven strains of Listeria spp. were isolate from 6 samples (7.15) among 84 samples of frozen foods, and ten strains of Listeria spp. were also isolated from 8 samples (7.6%)_ among 105 samples of refrigerated foods at the supermarkets in Pusan area. From a total of 189 commerical foods, the number of isolated Listeria spp. and ratio were 6 strains(3.25) of L. grayi, one strain (0.5%) of L. welshimeri, 6 strains (3.2%) of L. innocua and 4 strains (2.15) of L monocytogenes. Listeria spp. isolates except L. monocytogenes did not show $\beta$-hemolysis on blood agar and positive reaction in CAMP test with Staphyloccccus aureus. In the antibiotic susceptibility,most isolates of Listeria spp. were susceptible to 12 antibiotics such as ampicillin , cephalotin, penicillin, amikacin, gentamicin, erythromycin, kanamycin, vancomycin, tobramycin, carbenicillin , tetracycline and trimethoprim /sulfamethoxiazole. Four strains of L. monocytogenes were susceptible to ntibiotics used in this study except nitrofurantio. The serotype of 3 strains and one strain of L. monocytogenes were classified into Listeria O serotype 1 and 4, respectively.

• Food Science of Animal Resources
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• v.42 no.6
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• pp.1009-1019
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• 2022

In recent years, biocontrol of foodborne pathogens has become a concern in the food industry, owing to safety issues. Listeria monocytogenes is one of the foodborne pathogens that causes listeriosis. The major concern in the control of L. monocytogenes is its viability as it can survive in a wide range of environments. The purpose of this study was to isolate lactic acid bacteria with antimicrobial activity, evaluate their applicability as a cheese starter, and evaluate their inhibitory effects on L. monocytogenes. Lactococcus lactis strain with antibacterial activity was isolated from raw milk. The isolated strain was a low acidifier, making it a suitable candidate as an adjunct starter culture. The commercial starter culture TCC-3 was used as a primary starter in this study. Fresh cheese was produced using TCC-3 and L. lactis CAU2013 at a laboratory scale. Growth of L. monocytogenes (5 Log CFU/g) in the cheese inoculated with it was monitored during the storage at 4℃ and 10℃ for 5 days. The count of L. monocytogenes was 1 Log unit lower in the cheese produced using the lactic acid bacteria strain compared to that in the cheese produced using the commercial starter. The use of bacteriocin-producing lactic acid bacteria as a starter culture efficiently inhibited the growth of L. monocytogenes. Therefore, L. lactis can be used as a protective adjunct starter culture for cheese production and can improve the safety of the product leading to an increase in its shelf-life.

• Journal of Microbiology and Biotechnology
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• v.34 no.2
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• pp.349-357
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• 2024

Foodborne pathogens, like Listeria monocytogenes, continue to inflict substantial financial losses on the food industry. Various methods for detecting Listeria in food have been developed and numerous studies have been conducted to compare the different methods. But, in recent years, new Listeria species have been identified, and currently the genus comprises 26 species. Therefore, it would be a more accurate approach to re-evaluate existing detection methods by considering new species. The present investigation involved the analysis of 42 ready-to-eat (RTE) foods, encompassing a variety of food categories, such as mezes, salads, dairy products, and meat products, with the aim of ascertaining the presence of Listeria. Among the traditional culture-dependent reference methods, the ISO 11290 method was preferred. The process of strain identification was conducted with the API Identification System. Furthermore, to ascertain the existence of L. monocytogenes and Listeria spp., the samples underwent additional analysis employing the VIDAS Immunoassay System, ELISA, and RT-PCR methodologies. Thus, four alternative approaches were employed in this study to compare not only the different methods used to determine Listeria while taking into account the newly identified Listeria species, but also to assess the compliance of retail RTE food items with microbiological criteria pertaining to the genus Listeria. Based on the conducted analyses, L. monocytogenes was conclusively determined to be present in one sample. The presence of Listeria spp. was detected in 30.9% of the samples, specifically in Turkish cig kofte, sliced salami, and salads.

• Korean Journal of Veterinary Service
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• v.20 no.1
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• pp.69-77
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• 1997

To invastigate the epidemiological trait of listeriosis, Listeria monocytogenes were isolated from the carcasses of pigs and cattle, and environmental specimens in slaughter house. Also serotype of isolates were classified by rapid slide agglutination test. In the carcasses of pigs, Listeria sp were isolated from the carcasses after bleeding(62%), after dismemberment(60.0%) and before shipping(76.0%), and L monocytogenes were present in 8% of the carcasses after dismemberment and in 14% of the carcasses before shipping. However, few Listeria sp were isolated from the living body skin and the carcasses after scalding. In the carcasses of cattle, Listeria sp were isolated from the carcasses after bleeding(10%), after dismemberment(36.7%) and before shipping(63.3%), L monocytogenes were present in 3.3% of the carcasses after dismemberment and in 10% of the carcasses before shipping. Overall, L monocytogenes, L innocua, L welshimen, L grayi, and L murrayi were present In 4.8, 40, 2.3, 2.6 and 0.3% of all the carcasses, respectively. Prevalence of Listeria sp in environmental specimens were found to be 80% in slaughter house floors and 100% in sewage, and L monocytogenes were present in 15% of sewage. However, few Listeria sp were isolated from chilled water and from scalding water. Overall, L monocytogenes, L innocua, and L welshimeri were present in 3.8, 45 and 6.3% of all the environmental specimens, respectively. A total 27 strains of L monocytogenes were isolated from samples tested and all of the strains were classified into serotype 1.

• Journal of Food Hygiene and Safety
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• v.16 no.4
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• pp.251-257
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• 2001

Listeria monocytogenes and L. ivanovii are important food-pathogens for human and animal. The diagnostic of Listeria in food using culture medium requires time and laborwork, because there are many other non-pathogenic species like L. innocua, L welshimeri, L. seeligeri and L. grayi in Genus Listeria. For these reasons, Lismix multiplex PCR method was developed as a rapid method for the detection and identification of Listeria. In this study we developed a practical system of Lis-mix PCR detection for the application to food samples and new developed Siw-mix III PCR system overall 69 listerial strains were successful species-identified and confirmed. Also, the Siw-mix III PCR system allows the species-specific identification among L. ivanovii, L. welshimeri and L seeligeri in a single PCR.

• Food Science of Animal Resources
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• v.35 no.2
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• pp.211-215
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• 2015

From the previous study, Enterococcus faecium SH01 was isolated from mukeunji, an over-ripened kimchi, and it produced bacteriocin SH01. Bacteriocin SH01 showed an inhibitory effect against Listeria monocytogenes ATCC 19111, a bacterial strain causing human listeriosis. Crude bacteriocin SH01 was purified by ammonium sulfate precipitation and its inhibitory activity at two concentrations (500 and 1,000 AU/g) against Listeria monocytogenes ATCC 19111 was investigated in ground beef at increasing temperatures (5, 10, 15, and 20℃) for 8 d. The number of Listeria monocytogenes ATCC 19111 significantly decreased (p<0.05) as the concentration of bacteriocin increased from 500 to 1,000 AU/g. Intrinsic crude protease activities in ground beef were examined and increased as the temperature increased. Experiments varying both the concentrations of added bacteriocin SH01 and temperature demonstrated a maximum inhibition (2.33 log reduction of bacteria) in samples containing 1,000 AU/g of bacteriocin SH01 incubated at 20℃. When the crude bacteriocin SH01 solution (1,280 AU/mL) was incubated with crude protease solutions at different temperatures, its activity decreased by only half (640 AU/mL), as assessed in an agar well diffusion assay. The finding that the antilisterial activity of bacteriocin SH01 increased with temperature can be explained by the fact that higher temperatures increase bacterial membrane fluidity, thereby promoting the cellular penetration of bacteriocin SH01 into L. monocytogenes. Bacteriocin SH01 may be an excellent candidate as a biopreservative for controlling L. monocytogenes growth in ground beef.