• Journal of Food Hygiene and Safety
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• v.11 no.2
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• pp.107-114
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• 1996

The distribution of Listeria spp. in various foods and its fatty acid composition were examined. A total 60 samples of dairy products(15), seafoods(20), meat products(18), factory waster(2), and salades(5) were tested. Listeria spp. was found 10 samples, showing about 16.7% detection ratio; dairy products 0(0%),,seafoods 1(5%), meat product 7(38.9%), and factory wastes 2(100%). Whereas L. welshimeri was isolated from meat products 1(5.6%) and factory wastes 1(50%). The cellular fatty acid composition determined by gas chromatography was found not to differ among L. innocua isolated from food has similar fatty acid profiles when grown at 3$0^{\circ}C$,24 hrs on the tryptic soy plate with C15 and C17 anteiso branched acids accounting for about 80% of total.

• Korean Journal of Veterinary Service
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• v.23 no.4
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• pp.341-348
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• 2000

Nowadays we continue to face challenges to the safety of our foods. It seems clear that contaminated meats provide the major route of listeria monocytogenes transmission from the environment to humans. L monocytogenes is the most important species associated with disease in humans among the listeria sp. The current incidence of symptomatic listeriosis caused by L monocytogenes is uncertain. Although the number of reports in the literature on listeriosis are increasing, it is likely that they are actually unrecognized or underreported because of a lack of awareness on the part of some laboratory workers who fail to isolate or identify these organisms. To get the information of sanitary development, we survey various meats (beef, pork, etc) in Kyongbuk area. Samples were collected from local meat shop at Kyongbuk area. Total sixty six case were isolated and identified from one hundreds and seven samples. L innocua was the most abundant in listeria sp. Among U isolates, the number of isolated L innocua was 43 (65.2%). The numbers of isolated L murrayi, L welshimeri, L monocytogenes and L seeligeri were 12(18.2%), 7(10.6%), 3(4.5%) and 1(1.5%), respectively, but L grayi, L iuanouii were not Isolated.

• 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.

• 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.

• 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.

• Bulletin of Food Technology
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• v.18 no.1
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• pp.91-98
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• 2005

Aims: As a preliminary experiment on new sanitizer delivery tools, the efficacy of aerosolizedsanitizer on foodborne pathogens was investigated in larger model chamber system.Methods: Peroxyacetic acid and hydrogen peroxide were aerosolized in a model system againstartificially inoculated target microorganisms on laboratory media. Cultures of 4 different foodborne pathogens were inoculated and affixed onto 3 different heights (bottom, wall, and ceiling), and 3different orientations (face-down, vertical, and face-down) inside a commercial semi-trailer cabinet(14.6 x 2.6 x 2.8 m). Sanitizer was aerosolized into 2 m droplet size fog and treated for 1 h atambient temperature.Results: Populations of Bacillus cereus, Listeria innocua, Staphylococcus aureus, and Salmonellatyphimurium were reduced by an average of 3.09, 7.69, 6.93 and 8.18 log units per plate, respectively.Interestingly, L. innocua, Staph. aureus, and Salm. typhimurium showed statistically not different (P$\leq$ 0.05) reduction patterns relative to height and orientation that were never expected in a sprayingsystemConclusion and significance: Aerosolized sanitizers diffuse like gaseous sanitizers, so it has greatpotential for use in commercial applications.

• Journal of Food Hygiene and Safety
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• v.39 no.1
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• pp.9-15
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• 2024

This study was performed to survey the distribution of Listeria spp. in fresh agricultural products in the Busan area, the Republic of Korea, from January to November 2022. We investigated the pathogenicity and epidemiological relationships by tracing isolated strains using polymerase chain reaction and pulsed-field gel electro-phoresis (PFGE) methods. Forty cases of Listeria spp. were detected in the 210 samples of fresh agricultural products analyzed. Four species, Listeria rocourtiae, L. innocua, L. grayi, and L. monocytogenes were detected only in green vegetables (lettuce, perilla leaps) and the others (L. innocua, L. monocytogenes, and L. grayi) were detected in enoki and oyster mushrooms. L. innocua was detected in 22 samples and L. grayi in six samples. L. monocytogenes, which causes foodborne diseases, was only detected in enoki mushrooms and the strains that were isolated had genes responsible for the pathogenicity of listeriosis (iap, prfA, inlA, inlC, inlJ, and hly). To investigate the genetic similarity and contamination route of L. monocytogenes, serotyping and PFGE were conducted for 12 strains isolated from fresh agricultural (10 strains) and poultry (2 strains) products distributed at a market in the Busan area. Two serotypes (1/2a, 1/2b) were detected in strains isolated from the agricultural and poultry products, but serotype 1/2b was only detected in strains isolated from agricultural products. PFGE analysis showed index of similarity values of 45.7 to 100% and the same patterns were represented in isolates from some enoki mushrooms. These isolates had the same serotypes and showed significant epidemiological relationships.

• Food Science of Animal Resources
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• v.34 no.5
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• pp.665-673
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• 2014

We compared standard culture methods as well as conventional PCR and real-time PCR for the detection of Listeria monocytogenes (L. monocytogenes) in milk, cheese, fresh-cut vegetables, and raw beef that have different levels of background microflora. No statistical differences were observed in sensitivity between the two selective media in all foods. In total, real-time PCR assay exhibited statistically excellent detection sensitivity (p<0.05) and was less time consuming and laborious as compared with standard culture methods. Conventional culture methods showed poor performance in detecting L. monocytogenes in food with high levels of background microflora, generating numerous false negative results. While the detection of L. monocytogenes in fresh cut vegetable by culture methods was hindered only by L. innocua, various background microflora, such as L. innocua, L. welshimeri, L. grayi, and Enterococcus faecalis appeared on the two selective media as presumptive positive colonies in raw beef indicating the necessity of improvement of current selective media. It appears that real-time PCR is an effective and sensitive presumptive screening tool for L. monocytogenes in various types of foods, especially foods samples with high levels of background microflora, thus complementing standard culture methodologies.

• Journal of Food Hygiene and Safety
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• v.18 no.1
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• pp.25-29
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• 2003

The p60 protein of Listeria spp. is a Listeria-Genus-specific, major extra-cellular protein, which is used as an indicator protein for the detection of these bacteria from contaminated foods. In this study, p60 protein were recombinantly produced in E. coli and were purified using amylose resin based column chromatography. Purified recombinant-p6O was used to generate monoclonal antibody against native p60. Antibody from hybridoma cell line, 1H4, specificically reacted with native p60 protein isolated from pathogenic Listeria spp. such as L. monocytogenes, L. ivanovii, L. welshimeri II, but did not or relatively weakly reacted with non-pathogenic Listeia species, L. innocua or other bacterial proteins. Antibody from 1H4 was produced using ascites fluid method and it may be useful to develop the Listeria-detection kits based on immunological method.

• Journal of Microbiology and Biotechnology
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• v.9 no.4
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• pp.398-403
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• 1999

In our previous studies, we reported that hybridoma B-lymphocytes can be used to determine the virulence of Listeria species in an in vitro cytotoxicity assay. Here, we examined the cytopathic effect, i.e., membrane damage and the nature of cell death induced by Listeria monocytogenes on murine hybridoma B-lymphocytes (Ped-2E9). Membrane damage was assessed by microscopic analyses and by measuring the release of intracellular alkaline phosphatase(AP) and lactate dehydrogenase (LDH). Cell death was determined by DNA fragmentation analyses using agarose gel electrophoresis. Infection by listeriolysin O (LLO)-producing L. monocytogenes strains induced substantial amounts of AP and LDH release from Ped-2E9 hybridoma B-cells, suggesting severe membrane damage in these cells, while an LLO-negative L. monocytogenes mutant strain had no effect. An LLO-producing recombinant L. innocua ($prifA^+hly^+$) strain also induced high AP and LDH release and cytopathic changes in Ped-2E9 cells. Light or scanning electron microscopic examination revealed L. monocytogenes mediated membrane destabilization, pore formation, intense cytoplasmic granulation, bleb formation, and lysis of Ped-2E9 cells. LLO-producing L. monocytogenes and L. innocua ($prifA^{+}hly{^}+$) also induced ladder-like DNA fragmentation in Ped-2E9 cells. Collectively, these results suggest that L. monocytogenes, specifically LLO-producing strains, can induce a severe cytopathic effect leading to apoptosis in hybridoma B-lymphocytes (Ped-2E9).