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Microbial Indicators and Possible Focal Points of Contamination during Production and Processing of Catfish. Foods 2022; 11:foods11182778. [PMID: 36140905 PMCID: PMC9497987 DOI: 10.3390/foods11182778] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 09/03/2022] [Accepted: 09/05/2022] [Indexed: 12/04/2022] Open
Abstract
The catfish industry is important to the United States economy. The present study determined the levels of microbial indicators and the prevalence of Listeria spp. and Listeria monocytogenes at catfish farms and catfish processing plants. Live fish, water, and sediment samples were analyzed in farms. Fish skin, fillets, chiller water, and environmental surfaces were assessed at the processing plants both during operation and after sanitation. Live fish had 2% prevalence of Listeria monocytogenes, while sediment and water were negative for Listeria. Live fish skin counts averaged 4.2, 1.9, and 1.3 log CFU/cm2 aerobic (APC), total coliform (TCC) and generic Escherichia coli counts, respectively. Water and sediment samples averaged 4.8 and 5.8 log CFU/g APC, 1.9 and 2.3 log CFU/g TCC, and 1.0 and 1.6 log CFU/g generic E. coli counts, respectively. During operation, Listeria prevalence was higher in fillets before (57%) and after (97%) chilling than on fish skin (10%). Process chiller water had higher (p ≤ 0.05) APC, TCC, and Listeria prevalence than clean chiller water. After sanitation, most sampling points in which Listeria spp. were present had high levels of APC (>2.4 log CFU/100 cm2). APC combined with Listeria spp. could be a good approach to understand microbial contamination in catfish plants.
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Kang CY, Yu HW, Guo RF, Tan JX, Jia YM. Genetic diversity of isolates of foodborne Listeria monocytogenes by RAPD-PCR. ANN MICROBIOL 2016. [DOI: 10.1007/s13213-015-1186-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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3
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Park S, Jung H, Lee M, Choi H, Kim J, Jung J, Park S, Kim M, Kim K, Oh Y, Chung A, Jung K. Detection of <i>Listeria monocytogenes</i> in Foods and Characterization by PFGE. ACTA ACUST UNITED AC 2016. [DOI: 10.4236/aim.2016.64033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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4
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Ahn SH, Lee YJ, Lee JY, Paik HD. Microbiological Investigation of Ready-to-cook Pork Bulgogi on Korean Markets. Korean J Food Sci Anim Resour 2012. [DOI: 10.5851/kosfa.2012.32.4.441] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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5
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Park S, Jung J, Choi S, Oh Y, Lee J, Chae H, Ryu S, Jung H, Park G, Choi S, Kim B, Kim J, Zoo Chae Y, Jung B, Lee M, Kim H. Molecular Characterization of <i>Listeria monocytogenes</i> Based on the PFGE and RAPD in Korea. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/aim.2012.24079] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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7
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Tracing the food sources of isolated strains of Listeria monocytogenes through fatty acid profiles analysis. Food Control 2010. [DOI: 10.1016/j.foodcont.2010.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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8
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Bueno VF, Banerjee P, Banada PP, José de Mesquita A, Lemes-Marques EG, Bhunia AK. Characterization of Listeria monocytogenes isolates of food and human origins from Brazil using molecular typing procedures and in vitro cell culture assays. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2010; 20:43-59. [PMID: 20104385 DOI: 10.1080/09603120903281283] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The spreading of diseases through foods is a worldwide concern. Here, molecular and in vitro cell-culture assays were employed to characterize 63 Brazilian Listeria monocytogenes isolates (food, 47; clinical, 16). Serotype 4b was the most predominant (49%) followed by (1/2)b (30%), (1/2)a (10%), (1/2)c (6%), 3c (3%) and 3b (2%). Ribotyping yielded 17 ribopatterns, which were grouped into four phylogenetic clusters. Cluster A comprised of 39/63 isolates primarily of food origin, and clusters B, C and D contained both food and clinical isolates. Isolates were positive for virulence determinants prfA, hlyA and inlA: clinical isolates were more invasive to Caco-2 cells and expressed high levels of inlA transcripts than the food isolates. Highly invasive isolates also provoked more Ped-2E9 cells to die by apoptosis than the weakly-invasive strains. These data demonstrate a strong genetic relatedness among clinical and food isolates and suggest transmission of a subset of L. monocytogenes strains from food to humans.
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Affiliation(s)
- Valter F Bueno
- Department of Veterinary Medicine, Federal University of Goiás, Goiânia, Brazil
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D'Amico DJ, Donnelly CW. Detection, isolation, and incidence of Listeria spp. in small-scale artisan cheese processing facilities: a methods comparison. J Food Prot 2009; 72:2499-507. [PMID: 20003731 DOI: 10.4315/0362-028x-72.12.2499] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Environmental sampling, focused on environmental sites with a high probability of contamination, was conducted in eight artisan cheese processing facilities. Samples (n = 236) from 86 food contact surfaces and 150 non-food contact surfaces were examined for the presence of Listeria spp. by comparing the efficacy of three different primary enrichment media used in five detection and isolation methods. University of Vermont broth was the most sensitive primary enrichment medium for the detection of Listeria spp., including Listeria monocytogenes. These results, however, did not differ significantly from those obtained with Listeria repair broth or Oxoid 24 Listeria enrichment broth. When full methods were considered, the use of dual enrichment methods identified the most Listeria spp.-positive samples, whereas the BAX System PCR Assay for the Genus Listeria 24E provided the most rapid results (approximately 30 h). Cultural results from the direct plating of secondary enrichment broths were generally in agreement with PCR results when compared within methods. Despite minor differences in efficacy, all five methods were in agreement with one another. Overall, 24 (10.7%) of the 236 environmental samples were positive for Listeria spp., all of which were collected from non-food contact surfaces. Nine of these sites were also positive in previous sampling events, suggesting that these sites serve as Listeria niches and that certain ribotypes are particularly persistent, inhabiting environments and specific sites for over 2 years. Overall, our results suggest that the extent of Listeria spp. contamination, notably L. monocytogenes, in small-scale artisan cheese processing environments is low.
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Affiliation(s)
- Dennis J D'Amico
- Department of Nutrition and Food Sciences, University of Vermont, Burlington, Vermont 05405, USA.
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Meloni D, Galluzzo P, Mureddu A, Piras F, Griffiths M, Mazzette R. Listeria monocytogenes in RTE foods marketed in Italy: Prevalence and automated EcoRI ribotyping of the isolates. Int J Food Microbiol 2009; 129:166-73. [DOI: 10.1016/j.ijfoodmicro.2008.11.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 11/07/2008] [Accepted: 11/10/2008] [Indexed: 10/21/2022]
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11
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D'Amico DJ, Donnelly CW. Enhanced detection of Listeria spp. in farmstead cheese processing environments through dual primary enrichment, PCR, and molecular subtyping. J Food Prot 2008; 71:2239-48. [PMID: 19044268 DOI: 10.4315/0362-028x-71.11.2239] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The incidence and ecology of Listeria spp. in farmstead cheese processing environments were assessed through environmental sampling conducted in nine different plants over a 10-week period. Environmental samples (n = 705) were examined for the presence of Listeria spp. by using three detection/isolation protocols. The use of dual enrichment methods, which allowed for the recovery of injured Listeria spp. (mUSDA), identified more Listeria species-positive samples with higher sensitivity than the standard USDA method. The addition of PCR to the mUSDA method identified the most Listeria monocytogenes-positive samples, achieving greater sensitivity of detection while substantially reducing time. Overall, 7.5% of samples were positive for Listeria spp., yielding 710 isolates, 253 of which were subtyped by automated ribotyping to examine strain diversity within and between plants over time. The isolation of specific ribotypes did not appear to be affected by the enrichment protocol used. Fifteen (2.1%) samples yielded L. monocytogenes isolates differentiated almost equally into ribotypes of lineages I and II. Of most concern was the persistent and widespread contamination of a plant with L. monocytogenes DUP-1042B, a ribotype previously associated with multiple outbreaks of listeriosis. Our results suggest that the extent of contamination by Listeria spp., notably L. monocytogenes, in farmstead cheese plants is comparatively low, especially for those with on-site farms. The results of this study also identified points of control for use in designing more effective Listeria spp. control and monitoring programs with a focus on ribotypes of epidemiological significance.
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Affiliation(s)
- Dennis J D'Amico
- Department of Nutrition and Food Sciences, University of Vermont, Burlington, Vermont 05405, USA
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13
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Romanova NA, Gawande PV, Brovko LY, Griffiths MW. Rapid methods to assess sanitizing efficacy of benzalkonium chloride to Listeria monocytogenes biofilms. J Microbiol Methods 2007; 71:231-7. [PMID: 17928079 DOI: 10.1016/j.mimet.2007.09.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Revised: 09/06/2007] [Accepted: 09/09/2007] [Indexed: 11/25/2022]
Abstract
Different methods were used to investigate biofilm growth including crystal violet staining, ATP bioluminescence and total viable count. Seven strains of Listeria monocytogenes and 8 of their derivative strains were screened for their capacity to form biofilms. Both adaptation to benzalkonium chloride (BC) and curing of plasmids did not significantly affect biofilm-forming ability. The strains of L. monocytogenes belonging to serotype 1 formed biofilms significantly better as compared to serotype 4 (P=0.0003). To estimate the efficacy of BC for biofilm elimination the best and the poorest biofilm-formers were used (C719 and LJH 381). It was observed that, L. monocytogenes strain C719 in biofilms is at least 1000 times more resistant to BC than in planktonic form. Cells present in biofilms were shown to recover and grow after BC treatment thus providing a source of recontamination. It was shown that ATP bioluminescence provides good correlation with bacterial counts of L. monocytogenes in biofilms. Staining with crystal violet, on the contrary, did not correlate with bacterial growth in biofilms in the presence of high concentrations of BC but provided information on the concentration of bacterial cells, both live and dead, attached to the surface. ATP bioluminescence was found to be a reliable method for rapid estimation of the efficacy of sanitizers for biofilm disinfection. Crystal violet staining, on the other hand, was shown to be a suitable method to monitor removal of biofilms. Our investigation showed that for Listeria biofilms concentrations of BC higher then 10 mg/ml should be applied for at least 30 min to kill almost all the live cells in biofilms. However, this concentration was still not enough to remove biofilms from the surface of plastic.
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Affiliation(s)
- Nadya A Romanova
- Department of Food Science and Canadian Research Institute for Food Safety, University of Guelph, 43 McGilvray St., Guelph, Ontario, Canada N1G 2W1
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Fugett E, Fortes E, Nnoka C, Wiedmann M. International Life Sciences Institute North America Listeria monocytogenes strain collection: development of standard Listeria monocytogenes strain sets for research and validation studies. J Food Prot 2006; 69:2929-38. [PMID: 17186661 DOI: 10.4315/0362-028x-69.12.2929] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Research and development efforts on bacterial foodborne pathogens, including the development of novel detection and subtyping methods, as well as validation studies for intervention strategies can greatly be enhanced through the availability and use of standardized strain collections. These types of strain collections are available for some foodborne pathogens, such as Salmonella and Escherichia coli. We have developed a standard Listeria monocytogenes strain collection that has not been previously available. The strain collection includes (i) a diversity set of 25 isolates chosen to represent a genetically diverse set of L. monocytogenes isolates as well as a single hemolytic Listeria innocua strain and (ii) an outbreak set, which includes 21 human and food isolates from nine major human listeriosis outbreaks that occurred between 1981 and 2002. The diversity set represents all three genetic L. monocytogenes lineages (I, n = 9; II, n = 9; and III, n = 6) as well as nine different serotypes. Molecular subtyping by EcoRI automated ribotyping and pulsed-field gel electrophoresis (PFGE) with AscI and ApaI separated the 25 isolates in the diversity set into 23 ribotypes and 25 PFGE types, confirming that this isolate set represents considerable genetic diversity. Molecular subtyping of isolates in the outbreak set confirmed that human and food isolates were identical by ribotype and PFGE, except for human and food isolates for two outbreaks, which displayed related but distinct PFGE patterns. Subtype and source data for all isolates in this strain collection are available on the Internet and are linked to the PathogenTracker database (www.pathogentracker.com), which allows the addition of new, relevant information on these isolates, including links to publications that have used isolates from this collection. We have thus developed a core L. monocytogenes strain collection, which will provide a resource for L. monocytogenes research and development efforts with centralized Internet-based data curation and integration.
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Affiliation(s)
- Eric Fugett
- Department of Food Science, Cornell University, Ithaca, New York 14853, USA
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Aarnisalo K, Tallavaara K, Wirtanen G, Maijala R, Raaska L. The hygienic working practices of maintenance personnel and equipment hygiene in the Finnish food industry. Food Control 2006. [DOI: 10.1016/j.foodcont.2005.07.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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16
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Tominaga T. Rapid discrimination of Listeria monocytogenes strains by microtemperature gradient gel electrophoresis. J Clin Microbiol 2006; 44:2199-206. [PMID: 16757621 PMCID: PMC1489441 DOI: 10.1128/jcm.00344-06] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microtemperature gradient gel electrophoresis (mu-TGGE) was examined for use for the rapid subtyping of Listeria monocytogenes strains. Comparison of genomes between L. monocytogenes strains F2365 and H7858 identified a sequence encoding a portion of the PRT/PTS system IIA 2 protein domain as appropriate for mu-TGGE analysis. Thirty-one strains belonging to 10 different serovar types were tested by PCR, and sequence analysis of the amplified products revealed that the strains comprise 11 groups. All 55 possible pairs within the 11 groups were examined by mu-TGGE analysis. Of these, 47 pairs could be successfully discriminated, with a total electrophoresis time of only 7 min. Moreover, Cy3/Cy5 labeling allowed rapid identification of the sequence type in unknown strains of L. monocytogenes isolated from meat. These findings collectively indicate that mu-TGGE can be used for the rapid analysis of L. monocytogenes strains, facilitating determination of routes of contamination when these bacteria are found in food products.
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Affiliation(s)
- Tatsuya Tominaga
- Saitama Industrial Technology Center North Institute, 2-133, Suehiro, Kumagaya, Saitama 360-0031, Japan.
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17
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Corcoran D, Clancy D, O'Mahony M, Grant K, Hyland E, Shanaghy N, Whyte P, McLauchlin J, Moloney A, Fanning S. Comparison of Listeria monocytogenes strain types in Irish smoked salmon and other foods. Int J Hyg Environ Health 2006; 209:527-34. [PMID: 16872895 DOI: 10.1016/j.ijheh.2006.06.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 05/31/2006] [Accepted: 06/04/2006] [Indexed: 11/22/2022]
Abstract
An investigation of Listeria monocytogenes in Irish retail smoked salmon products and other unrelated food products was undertaken. Serotyping and genotyping methods were applied. Twenty-six L. monocytogenes isolates cultured from ready-to-eat smoked salmon and an additional 20 L. monocytogenes isolates from various commercially available food products (other than smoked salmon) were compared. Four serotypes, 12 ribotypes, 12 amplified fragment length polymorphism (AFLP) types and 17 pulsed-field gel electrophoresis (PFGE) types were identified among the 46 isolates studied. Genotyping identified a single dominant strain that accounted for 65% of those cultured from smoked salmon and this strain was present in product obtained from three out of five of the manufacturers surveyed. When compared to the food products obtained from a variety of sources, those from smoked salmon appeared to cluster as a single group. In Irish smoked salmon this strain may have adapted, and be capable of persisting in this food product. All isolates were grouped into genetic lineages based on their EcoR1 ribotypes. The attendant risk to public health following consumption of these foods is discussed.
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Affiliation(s)
- Deborah Corcoran
- Centre for Food Safety, School of Agriculture, Food Science and Veterinary Medicine, University College, Belfield, Dublin, Ireland
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Wagner M, Eliskases-Lechner F, Rieck P, Hein I, Allerberger F. Characterization of Listeria monocytogenes isolates from 50 small-scale Austrian cheese factories. J Food Prot 2006; 69:1297-303. [PMID: 16786849 DOI: 10.4315/0362-028x-69.6.1297] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
One hundred eighty-one small-scale cheese factories (annual production < 100,000 kg) were tested for the presence of Listeria monocytogenes in cheese and smear samples from 1997 to 2000. In total, 2615 samples were drawn. Fifty (27.6%) of 181 enterprises yielded L. monocytogenes. From 14 of the cheese-making facilities, we obtained more than four L. monocytogenes isolates. A total of 182 mostly cheese- and smear-borne L. monocytogenes strains were characterized by serotyping and pulsed-field gel electrophoresis. In 12 of 14 cheese factories, over half of the L. monocytogenes isolates were genetically indistinguishable by pulsetype. On average, genetically indistinguishable isolates were recovered for 11.9 months. Regarding serotypes, 27.3% of the isolates were of serovar 4b. Inadequate personal hygiene could explain the high prevalence of serovar 4b isolates in small-scale cheesemaking facilities. Forty-two percent of the serovar 4b isolates recovered from epidemiologically unlinked facilities (in comparison to 40 and 29% of the 1/2a and 1/2b isolates, respectively) were genetically indistinguishable from at least one other isolate. Indistinguishable serovar 1/2a and 1/2b isolates belonged to five and six different pulsetypes, respectively, whereas serovar 4b isolates belonged to only two pulsetypes. This finding suggested a wide distribution of genetically homologous serovar 4b isolates among the facilities tested in our study.
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Affiliation(s)
- M Wagner
- Department for Veterinary Public Health and Food Science, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria.
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19
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Churchill RLT, Lee H, Hall JC. Detection of Listeria monocytogenes and the toxin listeriolysin O in food. J Microbiol Methods 2005; 64:141-70. [PMID: 16310269 DOI: 10.1016/j.mimet.2005.10.007] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Revised: 10/14/2005] [Accepted: 10/14/2005] [Indexed: 10/25/2022]
Abstract
Listeria monocytogenes is an emerging bacterial foodborne pathogen responsible for listeriosis, an illness characterized by meningitis, encephalitis, and septicaemia. Less commonly, infection can result in cutaneous lesions and flu-like symptoms. In pregnant women, the pathogen can cause bacteraemia, and stillbirth or premature birth of the fetus. The mortality rate for those contracting listeriosis is approximately 20%. Currently, the United States has a zero tolerance policy regarding the presence of L. monocytogenes in food, while Canada allows only 100 cfu/g of food. As such, it is essential to be able to detect the pathogen in low numbers in food samples. One of the best ways to detect and confirm the pathogen is through the detection of one of the virulence factors, listeriolysin O (LLO) produced by the microorganism. The LLO-encoding gene (hlyA) is present only in virulent strains of the species and is required for virulence. LLO is a secreted protein toxin that can be detected easily with the use of blood agar or haemolysis assays and it is well characterized and understood. This paper focuses on some of the common methods used to detect the pathogen and the LLO toxin in food products and comments on some of the potential uses and drawbacks for the food industry.
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Affiliation(s)
- Robin L T Churchill
- Department of Environmental Biology, University of Guelph, Guelph, ON, Canada
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Suihko ML, Kroppenstedt RM, Stackebrandt E. Occurrence and characterization of actinobacteria and thermoactinomycetes isolated from pulp and board samples containing recycled fibres. J Ind Microbiol Biotechnol 2005; 33:183-91. [PMID: 16292555 DOI: 10.1007/s10295-005-0055-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Accepted: 10/18/2005] [Indexed: 10/25/2022]
Abstract
The aim of this study was to characterize the actinobacterial population present in pulps and boards containing recycled fibres. A total of 107 isolates was identified on the basis of their pigmentation, morphological properties, fatty acid profiles and growth temperature. Of the wet pulp and water sample isolates (n=87), 74.7% belonged to the genus Streptomyces, 17.2% to Nocardiopsis and 8.0% to thermoactinomycetes, whereas all the board sample isolates (n=20) were thermoactinomycetes. The identification of 53 isolates was continued by molecular methods. Partial 16S rDNA sequencing and automated ribotyping divided the Streptomyces isolates (n=31) into 14 different taxa. The most common streptomycetes were the mesophilic S. albidoflavus and moderately thermophilic S. thermocarboxydus. The Nocardiopsis isolates (n=11) belonged to six different taxa, whereas the thermoactinomycetes were mainly members of the species Laceyella sacchari (formerly Thermoactinomyces sacchari). The results indicated the probable presence of one or more new species within each of these genera. Obviously, the drying stage used in the board making processes had eliminated all members of the species Streptomyces and Nocardiopsis present in the wet recycled fibre pulp samples. Only the thermotolerant endospores of L. sacchari were still present in the final products. The potential of automated ribotyping for identifying actinobacteria was indicated, as soon as comprehensive identification libraries became available.
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Affiliation(s)
- M-L Suihko
- VTT Biotechnology, PO Box 1500, 02044 VTT, Finland.
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Berrang ME, Meinersmann RJ, Frank JF, Smith DP, Genzlinger LL. Distribution of Listeria monocytogenes subtypes within a poultry further processing plant. J Food Prot 2005; 68:980-5. [PMID: 15895730 DOI: 10.4315/0362-028x-68.5.980] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Samples from environmental sites and raw product in a chicken further processing plant were collected every 6 weeks for 12 months. Each sample site was examined before and after a complete production shift. All samples were examined for the presence of Listeria monocytogenes, which was detected in floor drains on the raw product side of the plant preoperation and in drains on both raw and cooked sides following 8 h of processing operation. L. monocytogenes also was detected in raw product and once in fully cooked product but never on cooked product contact surfaces. One hundred sixty-one isolates were collected from 75 positive samples. All isolates were subtyped using a sequence-based method, and 14 unique subtypes were detected through the course of the study. Four of these types were found repeatedly and appeared to be resident in the plant. Three of the four resident strains were detected on raw product at some point during the year-long study, suggesting that raw product may be one source of L. monocytogenes in the processing plant environment. These data highlight the need for research to investigate why some types of L. monocytogenes persist in a processing plant environment but others do not.
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Affiliation(s)
- M E Berrang
- US Department of Agriculture, Agricultural Research Service, Russell Research Center, Athens, Georgia 30605, USA.
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Gasanov U, Hughes D, Hansbro PM. Methods for the isolation and identification of Listeria spp. and Listeria monocytogenes: a review. FEMS Microbiol Rev 2004; 29:851-75. [PMID: 16219509 DOI: 10.1016/j.femsre.2004.12.002] [Citation(s) in RCA: 216] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2004] [Revised: 10/07/2004] [Accepted: 12/10/2004] [Indexed: 11/18/2022] Open
Abstract
Listeria monocytogenes is an important food-borne pathogen and is widely tested for in food, environmental and clinical samples. Identification traditionally involved culture methods based on selective enrichment and plating followed by the characterization of Listeria spp. based on colony morphology, sugar fermentation and haemolytic properties. These methods are the gold standard; but they are lengthy and may not be suitable for testing of foods with short shelf lives. As a result more rapid tests were developed based on antibodies (ELISA) or molecular techniques (PCR or DNA hybridization). While these tests possess equal sensitivity, they are rapid and allow testing to be completed within 48 h. More recently, molecular methods were developed that target RNA rather than DNA, such as RT-PCR, real time PCR or nucleic acid based sequence amplification (NASBA). These tests not only provide a measure of cell viability but they can also be used for quantitative analysis. In addition, a variety of tests are available for sub-species characterization, which are particularly useful in epidemiological investigations. Early typing methods differentiated isolates based on phenotypic markers, such as multilocus enzyme electrophoresis, phage typing and serotyping. These phenotypic typing methods are being replaced by molecular tests, which reflect genetic relationships between isolates and are more accurate. These new methods are currently mainly used in research but their considerable potential for routine testing in the future cannot be overlooked.
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Affiliation(s)
- Uta Gasanov
- Immunology and Microbiology, Biomedical Sciences, Faculty of Health, The University of Newcastle, Australia; Vaccines, Immunology/Infection, Viruses and Asthma Group, The Hunter Medical Research Institute, Newcastle, Australia
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Somers EB, Wong ACL. Efficacy of two cleaning and sanitizing combinations on Listeria monocytogenes biofilms formed at low temperature on a variety of materials in the presence of ready-to-eat meat residue. J Food Prot 2004; 67:2218-29. [PMID: 15508633 DOI: 10.4315/0362-028x-67.10.2218] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Biofilms in the food-processing industry are a serious concern due to the potential for contamination of food products, which may lead to decreased food quality and safety. The effect of two detergent and sanitizer combinations on the inactivation of Listeria monocytogenes biofilms was studied. Combination A uses a chlorinated-alkaline, low-phosphate detergent, and dual peracid sanitizer. Combination B uses a solvated-alkaline environmental sanitation product and hypochlorite sanitizer. The survival of bacterial biofilms placed at 4 and 10 degrees C and held for up to 5 days was also addressed. To simulate conditions found in a ready-to-eat meat-processing environment, biofilms were developed in low-nutrient conditions at 10 degrees C (with and without meat and fat residue) on a variety of materials found in a plant setting. Included were two types of stainless steel, three materials for conveyor use, two rubber products, a wall, and floor material. Biofilms developed on all surfaces tested; numbers at day 2 ranged from 3.2 log on silicone rubber to 4.47 log CFU/cm2 on Delrin, an acetal copolymer. Biofilm survival during storage was higher at 4 degrees C (36.3 to 1,621%) than 10 degrees C (4.5 to 83.2%). Small amounts of meat extract, frankfurters, or pork fat reduced biofilm formation initially; with time, the biofilm cell number and survival percentage increased. Cleaning efficacy was surface dependent and decreased with residue-soiled surfaces; biofilms developed on the brick and conveyor material were most resistant. Both detergents significantly (P < 0.05) removed or inactivated biofilm bacteria. The sanitizers further reduced biofilm numbers; however, the reduction was not significant in most cases for the dual peracid. Using a benchmark efficacy of >3-log reduction, combination A was only effective on 50.0% of the samples, Combination B, at 86.1%, was more effective.
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Affiliation(s)
- Eileen B Somers
- University of Wisconsin-Madison, Department of Food Microbiology and Toxicology, Food Research Institute, 1925 Willow Drive, Madison, Wisconsin 53706, USA
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Fonnesbech Vogel B, Fussing V, Ojeniyi B, Gram L, Ahrens P. High-resolution genotyping of Listeria monocytogenes by fluorescent amplified fragment length polymorphism analysis compared to pulsed-field gel electrophoresis, random amplified polymorphic DNA analysis, ribotyping, and PCR-restriction fragment length polymorphism analysis. J Food Prot 2004; 67:1656-65. [PMID: 15330530 DOI: 10.4315/0362-028x-67.8.1656] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The purpose of this study was to evaluate fluorescent amplified fragment length polymorphism (AFLP) analysis for the inter- and intraspecies differentiation of a collection of 96 strains of Listeria monocytogenes and 10 non-L. monocytogenes strains representing six other Listeria species of different origin. The AFLP technique was compared with three other molecular typing methods--ribotyping, random amplified polymorphic DNA analysis (RAPD), and pulsed-field gel electrophoresis (PFGE)--in terms of discriminatory ability. PCR-restriction fragment length polymorphism was included for virulence gene allele characterization. The 96 L. monocytogenes strains were divided into two major clusters by AFLP fingerprinting at a similarity level of 82% in concordance with the results of PFGE, RAPD, and ribotyping. One main cluster consisted of all of the 24 L. monocytogenes hly allele 1 strains, while another main cluster consisted of all of the 72 L. monocytogenes hly allele 2 strains. This indicates the existence of two distinct phylogenetic divisions. Isolates of the remaining Listeria species were not included in the clusters. AFLP, PFGE, and RAPD typing were highly discriminatory methods, with discrimination (D) indices of 0.974, 0.969, and 0.954, respectively, whereas ribotyping had a lower D index of 0.874. AFLP, PFGE, and RAPD typing showed some level of agreement in terms of strain grouping and differentiation. However, all three methods subdivided types of strains grouped by the other methods. Isolates with identical DNA profiles were distributed across the spectrum of origin. It was not possible to associate certain types with specific food sectors or clinical cases, which is indicative of the spread of L. monocytogenes clones across species. Overall, AFLP fingerprinting was suitable for the high-resolution genotyping of L. monocytogenes and had an equally high or higher differentiation power compared to PFGE or RAPD typing.
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Affiliation(s)
- Birte Fonnesbech Vogel
- Danish Institute for Fisheries Research, Department of Seafood Research, Søltofts Plads, c/o Technical University of Denmark, Building 221, DK-2800 Kgs Lyngby, Denmark.
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Lukinmaa S, Aarnisalo K, Suihko ML, Siitonen A. Diversity of Listeria monocytogenes isolates of human and food origin studied by serotyping, automated ribotyping and pulsed-field gel electrophoresis. Clin Microbiol Infect 2004; 10:562-8. [PMID: 15191386 DOI: 10.1111/j.1469-0691.2004.00876.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Automated ribotyping, pulsed-field gel electrophoresis (PFGE) and serotyping were evaluated for the epidemiological study of isolates of Listeria monocytogenes collected in Finland in 1997-1999 from human blood (n = 116) and the food industry (n = 72). The isolates divided into six serotypes, 23 EcoRI ribotypes, 54 AscI PFGE types, and 57 final subtypes if all results were combined. The discrimination index of ribotyping was lower (0.873) than that of PFGE (0.946). Two final subtypes dominated among human isolates, and identical subtypes were also found among food industry isolates. All PFGE types were serotype-specific, whereas two ribotypes included isolates of two serotypes. Isolates of serotype 3a, involved in an outbreak in Finland in 1999, matched one of these ribotypes, which also included some food industry isolates of serotype 1/2a. Ribotyping with EcoRI would not have been sufficient to define the outbreak in Finland caused by serotype 3a isolates. Although ribotyping is applicable as the first method in outbreak situations, human and food isolates with identical ribotypes should be investigated further by PFGE.
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Affiliation(s)
- S Lukinmaa
- Laboratory of Enteric Pathogens, National Public Health Institute, Helsinki, Finland
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26
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Gudbjörnsdóttir B, Suihko ML, Gustavsson P, Thorkelsson G, Salo S, Sjöberg AM, Niclasen O, Bredholt S. The incidence of Listeria monocytogenes in meat, poultry and seafood plants in the Nordic countries. Food Microbiol 2004. [DOI: 10.1016/s0740-0020(03)00012-1] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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27
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Gendel SM. Riboprint analysis of Listeria monocytogenes isolates obtained by FDA from 1999 to 2003. Food Microbiol 2004. [DOI: 10.1016/s0740-0020(03)00054-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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28
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Lundén JM, Autio TJ, Sjöberg AM, Korkeala HJ. Persistent and nonpersistent Listeria monocytogenes contamination in meat and poultry processing plants. J Food Prot 2003; 66:2062-9. [PMID: 14627284 DOI: 10.4315/0362-028x-66.11.2062] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Contamination analysis of persistent and nonpersistent Listeria monocytogenes strains in three meat processing plants and one poultry processing plant were performed in order to identify factors predisposing to or sustaining persistent plant contamination. A total of 596 L. monocytogenes isolates were divided into 47 pulsed-field gel electrophoresis (PFGE) types by combining the restriction enzyme patterns of AscI (42 patterns) and ApaI (38 patterns). Persistent and nonpersistent strains were found in all plants. Nonpersistent PFGE types were found mostly at one sampling site, with the processing environment being the most common location, whereas the persistent strains were found at several sampling sites in most cases. The processing machines were frequently contaminated with persistent L. monocytogenes PFGE types, and it was of concern that surfaces having direct contact with the products were contaminated. The role of the processing machines in sustaining contamination and in contaminating the products appeared to be important because the final product of several processing lines was contaminated with the same L. monocytogenes PFGE type as that found in the processing machine. The proportion of persistent PFGE types in heat-treated products was eight times higher than in the raw products, showing the importance of the persistent PFGE types as contaminants of the final heat-treated products. The contamination status of the processing lines and machines appeared to be influenced by the compartmentalization of the processing line, with poor compartmentalization increasing L. monocytogenes contamination. The separation of raw and post-heat treatment areas seemed especially important in the contamination status of post-heat treatment lines.
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Affiliation(s)
- Janne M Lundén
- Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland.
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Aarnisalo K, Autio T, Sjöberg AM, Lundén J, Korkeala H, Suihko ML. Typing of Listeria monocytogenes isolates originating from the food processing industry with automated ribotyping and pulsed-field gel electrophoresis. J Food Prot 2003; 66:249-55. [PMID: 12597485 DOI: 10.4315/0362-028x-66.2.249] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A total of 486 Listeria monocytogenes isolates originating from 17 Finnish food processing plants (representing meat, poultry, fish, and dairy production) were collected and typed by automated ribotyping using EcoRI as the restriction enzyme. The isolates were divided into 16 different ribotypes (RTs). Some of these isolates (121), representing all EcoRI types and 16 food plants, were subjected to ribotyping with the PvuII enzyme, to pulsed-field gel electrophoresis (PFGE) typing with AscI and SmaI restriction enzymes, and to serotyping with O-antigen antisera. Nineteen ribotypes were generated with PvuII, 42 macrorestriction patterns were generated with AscI and 24 with SmaI, and three serotypes were generated with antisera. When the results were combined, the overall number of RTs was 23, and that of the PFGE types was 46. Thus, the overall discrimination power of PFGE was higher (discrimination index [DI] 0.966) than that of ribotyping (DI 0.906). The most common serotype (90.1% of the isolates) was 1/2, and isolates of serotype 4 (3.3%) were rare. There was no connection between food sectors and RTs or PFGE types, but PFGE indicated the single plants (78.3% of the types) better than ribotyping (56.5%). On the basis of its automation and on the availability of identification databases, automated ribotyping had some advantages over PFGE. Overall, automated ribotyping can be considered a practical and rapid tool when Listeria contamination is suspected and when screening a large number of isolates is necessary, e.g., when tracing contamination sources. However, in cases of outbreaks, the identical patterns must be confirmed by PFGE, which is a more discriminatory method.
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Autio T, Keto-Timonen R, Lundén J, Björkroth J, Korkeala H. Characterisation of Persistent and Sporadic Listeria monocytogenes Strains by Pulsed-Field Gel Electrophoresis (PFGE) and Amplified Fragment Length Polymorphism (AFLP). Syst Appl Microbiol 2003; 26:539-45. [PMID: 14666982 DOI: 10.1078/072320203770865846] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study was set up to evaluate the genetic similarity or dissimilarity of persistent and sporadic Listeria monocytogenes strains existing in eleven food processing facilities, including fish, dairy, meat and poultry processing plants. In each plant persistent and sporadic strains were selected on the basis of PFGE typing results. A total of 17 strains representing persistent strains and 38 sporadic strains originating from eleven food processing plants were included in the study. PFGE macrorestriction patterns of persistent and sporadic strains from different processing plants were compared and the strains were further studied by amplified fragment length polymorphism (AFLP), being a characterisation method giving more whole genome based information. The 17 persistent and 38 sporadic strains showed 14 and 35 pulsotypes, 14 and 28 AFLP types, respectively. The combination of PFGE and AFLP typing results yielded a total of 48 genotypes. Thirteen of 15 genotypes presented by persistent strains were only associated with persistent strains and similarly 94% (33/35) of genotypes showed by sporadic strains were recovered among sporadic strains only. Our results showed that L. monocytogenes strains causing persistent contamination differ from sporadic strains. In AFLP analysis persistent strains did not, however, form any specific clusters and neither was there any difference between the known two genomic groups. These results indicate that even though persistent strains differ from sporadic strains there seems not to be any specific evolutional lineage of persistent strains.
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Affiliation(s)
- Tiina Autio
- Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland.
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Borch E, Arinder P. Bacteriological safety issues in red meat and ready-to-eat meat products, as well as control measures. Meat Sci 2002; 62:381-90. [DOI: 10.1016/s0309-1740(02)00125-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2002] [Revised: 04/10/2002] [Accepted: 04/27/2002] [Indexed: 10/27/2022]
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