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Lianou A, Sofos JN. A review of the incidence and transmission of Listeria monocytogenes in ready-to-eat products in retail and food service environments. J Food Prot 2007; 70:2172-98. [PMID: 17900099 DOI: 10.4315/0362-028x-70.9.2172] [Citation(s) in RCA: 259] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Contamination of ready-to-eat products with Listeria monocytogenes may occur at several stages before consumption. Accessibility to the public and relatively limited control interventions at retail and food service establishments (compared with the processing sector of the food industry) and the lack of a specific regulatory framework increase the likelihood of introduction of this pathogen into some foods in these establishments. This review is a compilation of available information on the incidence and transmission of L. monocytogenes through ready-to-eat products at the retail and food service level. The potential transmission of L. monocytogenes within retail and food service operations has been indicated in epidemiological investigations and by survey data. Potential sources of the organism in these operations include the environment, food handlers, and incoming raw ingredients or processed products that have become contaminated after the lethality treatment at the manufacturing facility. L. monocytogenes may be present at retail and food service establishments in various ready-to-eat products, both prepackaged and those packaged in the store, and occasionally at high concentrations. This issue dictates the need for development and application of effective control measures, and potential control approaches are discussed here. Good manufacturing practices, appropriate cleaning, sanitation and hygiene programs, and temperature control required for prevention or inhibition of growth of the pathogen to high levels are critical for control of L. monocytogenes in the retail and food service sector. A comprehensive food safety system designed to be functional in retail and food service operations and based on the philosophy of hazard analysis and critical control point systems and a series of sound prerequisite programs can provide effective control of L. monocytogenes in these environments. However, competent delivery of food safety education and training to retail and food service managers and food handlers must be in place for successful implementation of such a system.
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Affiliation(s)
- Alexandra Lianou
- Center for Red Meat Safety, Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523-1171, USA
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Hofer E, Ribeiro R, Feitosa DP. Species and serovars of the genus Listeria isolated from different sources in Brazil from 1971 to 1997. Mem Inst Oswaldo Cruz 2000; 95:615-20. [PMID: 10998209 DOI: 10.1590/s0074-02762000000500005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Using phenotype techniques, characterization was made to species and serovar of 3,112 strains of Listeria, isolated from different sources of infection such as human (247-7.9%) and animals (239-7.6%), as well as from various routes of infection, including food (2, 330-74.8%) and environmental constituents (296-9.5%), all coming from different regions of the country and collected during the period 1971-1997. The following species were recovered in the cultures analysed: L. monocytogenes (774-24.8%), L. innocua (2, 269-72.9%), L. seeligeri (37-1.1%), L. welshimeri (22-0.7%), L. grayi (9-0.2%), and L. ivanovii (1-0.03%). L. monocytogenes was represented by ten serovars, the most prevalent being 4b (352-11.3%), (1/2)a (162-5.2%), and (1/2)b (148-4.7%). The predominant serovar in L. innocua was 6a (2,093-67.2%). Considerations about laboratory methods for diagnosis and epidemiological aspects are presented on the basis of the results obtained.
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Affiliation(s)
- E Hofer
- Laboratório de Zoonoses Bacterianas, Departamento de Bacteriologia, Instituto Oswaldo Cruz, Rio de Janeiro, Brazil
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Gilot P, Genicot A, André P. Serotyping and esterase typing for analysis of Listeria monocytogenes populations recovered from foodstuffs and from human patients with listeriosis in Belgium. J Clin Microbiol 1996; 34:1007-10. [PMID: 8815071 PMCID: PMC228941 DOI: 10.1128/jcm.34.4.1007-1010.1996] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Listeria monocytogenes strains isolated in Belgium from different foodstuffs and in sporadic cases of human listeriosis were analyzed. The distribution of serovars differed in each of these populations. The bacteria isolated from cheeses and from human patients with listeriosis were further studied by esterase typing. The twenty esterase patterns defined were not equally distributed in these two populations. The secretion of the virulence determinant phosphatidylinositol-specific phospholipase C and the pathogenicity level of strains in immunocompromised mice could not explain the unequal distribution of esterase types. The discrimination index of esterase typing (DI = 0.868) was compared with that of serotyping (DI = 0.666) and with that of the two combined methods (DI = 0.899).
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Affiliation(s)
- P Gilot
- Belgian National Reference Centre for Listeriosis, Department of Microbiology, Institute of Hygiene and Epidemiology, Brussels, Belgium
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Sheridan JJ, Duffy G, McDowell DA, Blair IS. The occurrence and initial numbers of Listeria in Irish meat and fish products and the recovery of injured cells from frozen products. Int J Food Microbiol 1994; 22:105-13. [PMID: 8074965 DOI: 10.1016/0168-1605(94)90135-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A total of 549 samples of meat, fish and poultry products purchased from retail outlets in the Dublin area were examined for the presence of Listeria spp., using a standard recovery method and a new resuscitation method. Listeria spp. were most frequently isolated from frozen beef burgers (97%) and fish fingers (95%). Cooked meats which were prepackaged by the manufacturer were negative for Listeria spp. The pathogen was isolated from 21% of cooked meats which were sold retail unpackaged indicating post-process contamination. Standard recovery methods gave Listeria counts of between 0.7 and log10 5.0 cfu/g on frozen products. Using a resuscitation method, counts were up to log10 2.5 cfu/g higher, indicating the presence of large numbers of injured Listeria cells. The significance of the numbers of Listeria found in the various foods as well as the recovery of injured cells with the new resuscitation method is discussed.
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Affiliation(s)
- J J Sheridan
- National Food Centre, Teagasc, Dunsinea, Castleknock, Dublin, Ireland
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Ferron P, Michard J. Distribution of Listeria spp. in confectioners' pastries from western France: comparison of enrichment methods. Int J Food Microbiol 1993; 18:289-303. [PMID: 8347428 DOI: 10.1016/0168-1605(93)90152-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Three hundred samples of pastry from 100 different suppliers in western France, including butter-cream, whipped dairy cream and custard filled cakes from each supplier, were collected and tested for the occurrence of Listeria spp. in 25 g samples. Listeria spp. were detected in 21.7% of he samples: Listeria monocytogenes in 13.7%, Listeria innocua in 10% and Listeria seeligeri in 2.3%. Thirteen samples were contaminated with two species simultaneously. The frequency of contaminated samples was not related to the composition of the pastry filling used, but it seemed to increase with the number of aerobic contaminant microorganisms in the dairy cream-based samples. The contamination rate was dependent on the place of manufacture. The numbers of Listeria spp. and Listeria monocytogenes were estimated on positive samples at the 25 g level as follows: < 0.3/g, Listeria spp. in 47 samples, L monocytogenes in 27; 0.3-30/g, Listeria spp. in 13, L. monocytogenes in nine; 30-300/g, L. monocytogenes in one; 300-3000/g; L. monocytogenes in three; 700,000/g, L. monocytogenes in one. Various detection methods were tested, including two enrichments broths tested in parallel: a modified LEB broth using 10 mg/l acriflavine-HCl and the UVM 1 broth, with incubation at 30 degrees C and streaking onto PALCAM agar. The enrichment procedures were: (a) primary enrichment of 25 g sample and plating after 48 h and 7 days; (b) secondary enrichment by subculturing the primary enrichment broths incubated for 24 h and 6 days, into fresh enrichment broth, then plating after 24 h incubation; (c) pre-enrichment of 25 g sample for 24 h in the basal enrichment broths without inhibitors, followed by subculturing in complete broths which were plated after 24 h and 6 days incubation. In all cases, UVM performed better than the LEB broth. It was unnecessary to extend the primary enrichment period beyond 48 h. Secondary enrichments inoculated from 24-h incubated primary enrichments gave a slightly better isolation rate than primary enrichments. Secondary enrichments made from 6-day incubated primary enrichments gave no additional advantage. The pre-enrichment procedure had an efficiency higher than that obtained by primary enrichment.
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Affiliation(s)
- P Ferron
- Laboratoire Interrégional de la Direction Générale de la Concurrence, de la Consommation et de la Répression des Fraudes, Rennes, France
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Comi G, Frigerio R, Cantoni C. Listeria monocytogenes serotypes in Italian meat products. Lett Appl Microbiol 1992; 15:168-171. [DOI: 10.1111/j.1472-765x.1992.tb00754.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Listeria spp. have been isolated from various food items. This fact does not mean in any case a true health risk. A balanced appraisal should be based on quantitative as well as qualitative aspects. Actually, there is still an open debate whether a limited number of Listeria has to be tolerated at least in certain food items. In addition, the pathogenic potency of an isolate may be put into account. Pathogenicity of various Listeria spp. definitely varies. Most Listeria spp., except Listeria monocytogenes, can be regarded as harmless to man. Also, not all strains of L. monocytogenes are pathogenic: rough variants possess only reduced virulence; non-hemolytic mutants have completely lost their pathogenic potency. Furthermore, several other virulence factors may be lost under natural conditions, so that among the majority of hemolytic, pathogenic isolates there may be others which are non-pathogenic or of low virulence only. Unfortunately, these strains actually cannot be recognized and characterized by common laboratory tests, so that animal pathogenicity seems to be the only way to get a final conclusion on the health risk of an isolate of L. monocytogenes from any food. The problem raised by this is which animal test is able to predict a true health risk either for normal hosts or for immunocompromised patients?
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Affiliation(s)
- H Hof
- Institute of Medical Microbiology and Hygiene, Faculty of Clinical Medicine Mannheim, Germany
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Recommendations by The National Advisory Committee on microbiological criteria for foods. Int J Food Microbiol 1991. [DOI: 10.1016/0168-1605(91)90114-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Schlech WF. Lowbury Lecture. Listeriosis: epidemiology, virulence and the significance of contaminated foodstuffs. J Hosp Infect 1991; 19:211-24. [PMID: 1686033 DOI: 10.1016/0195-6701(91)90238-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Recent epidemiological evidence confirms that sporadic, as well as outbreak-associated, cases of listeriosis are primarily foodborne in origin. Implicated foodstuffs include meat products, dairy products, fruit, seafood and raw and processed vegetables. Large community-acquired outbreaks in North America and Europe have been complemented by smaller outbreaks involving hospitalized patients. Anecdotal reports and case clusters of nosocomial cases also support foodborne transmission. Cross-infection may be a major mode of transmission as demonstrated in a recent outbreak in Costa Rica. The sporadic nature of outbreaks of listeriosis are more consistent with changes in organism virulence rather than host susceptibility. The population of patients at risk for listeriosis (pregnant women and immunocompromised hosts) may not vary greatly. Establishment of infection is probably dose-dependent and gastric acidity may be protective. However, other organism-specific virulence factors, such as haemolysin production, may affect the post-intestinal phase of infection. Virulence factors other than haemolysins have not been characterized as yet. In summary, acquisition of Listeria monocytogenes infection from the environment by susceptible hosts may be widespread but invasive infection remains rare and the determinants of invasion require further elucidation.
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Affiliation(s)
- W F Schlech
- Department of Medicine, Dalhousie University
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Buchrieser C, Brosch R, Rocourt J. Use of pulsed field gel electrophoresis to compare large DNA-restriction fragments of Listeria monocytogenes strains belonging to serogroups 1/2 and 3. Int J Food Microbiol 1991; 14:297-304. [PMID: 1790106 DOI: 10.1016/0168-1605(91)90121-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Thirty-five Listeria monocytogenes strains belonging to serogroups 1/2 and 3 and isolated from various origins were characterized by whole cellular DNA restriction patterns using low-frequency cleavage enzymes and pulsed field gel electrophoresis. Seventeen restriction profiles were detected with ApaI, 18 with SmaI and 15 with NotI, the combination of these patterns allowing one to define at least 24 distinct groups within the 35 strains. The significant genomic diversity pointed out by this method can be of value in the epidemiological fingerprinting of L. monocytogenes.
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Affiliation(s)
- C Buchrieser
- National Reference Center for Phage Typing and Molecular Typing of Listeria, Paris, France
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Art D, André P. Clinical and epidemiological aspects of Listeriosis in Belgium, 1985-1990. ZENTRALBLATT FUR BAKTERIOLOGIE : INTERNATIONAL JOURNAL OF MEDICAL MICROBIOLOGY 1991; 275:549-56. [PMID: 1755927 DOI: 10.1016/s0934-8840(11)80177-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Between January 1985 and December 1990, 233 cases of human listeriosis were reported to the Listeria Reference Centre of Belgium. Foeto-maternal infections (88 cases) and septicemia in adults (88 cases) were the most frequent clinical manifestations, followed by CNS infections (40 cases). 71.7% of the patients presented a concurrent condition which favoured the triggering of the disease. No correlation was found between the isolation of L. monocytogenes in patients and their occupation or their animal environment. The predominant serovar was 4b (70%). On the other hand, the Reference Centre also examined 1412 foodstuffs for the presence of L. monocytogenes: 16.9% (9/53) of cooked chicken products, 15.4% (73/473) of soft cheeses and 6.9% (62/886) of cooked meat products were positive (presence of L. monocytogenes in 25 g). The contamination level of these ready-to-eat foodstuffs ranged from less than 10 cfu L. monocytogenes/g. to 10(6) cfu/g. 54.1% of the isolated strains belonged to serovar 1/2a.
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Affiliation(s)
- D Art
- Institut d'Hygiène et d'Epidémiologie, Département Microbiologie, Bruxelles, Belgique
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Art D, Andre P. Comparison of three selective isolation media for the detection of L. monocytogenes in foods. ZENTRALBLATT FUR BAKTERIOLOGIE : INTERNATIONAL JOURNAL OF MEDICAL MICROBIOLOGY 1991; 275:79-84. [PMID: 1930568 DOI: 10.1016/s0934-8840(11)80770-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
391 different foods were examined in order to compare three selective isolation media for Listeria: blood agar with nalidixic acid, Palcam agar, Listeria selective Oxford medium (Oxford agar). The percentage of positive samples (presence of Listeria in 25 g) obtained on the three media after an enrichment procedure is identical: 15.8%. The species L. monocytogenes is found in respectively 8.43%, 8.43% and 8.18% of the foods examined on Palcam agar, Oxford agar and nalidixic acid agar; this represents more than 50% of the isolates of the genus Listeria. However, Palcam agar and Oxford agar offer the advantages of a great reduction of the development of the contaminating microflora and a clearly less fastidious reading. The technique used for the direct counting of L. monocytogenes on these two selective media does not allow the detection of a low contamination of foods (theoretical positivity threshold = 100 Listeria/g): 65.2% of the positive samples would not have been detected without prior enrichment. 41.1% of the isolated L. monocytogenes belong to serovar 1/2a, 5.8% to serovar 1/2b, 20.58% to serovar 1/2c, 5.8% to serovar 3b and 24.47% to serovar 4b.
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Affiliation(s)
- D Art
- Institut d'Hygiène et d'Epidémiologie, Département Microbiologie, Bruxelles, Belgique
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Andre P, Roose H, Van Noyen R, Dejaegher L, Uyttendaele I, de Schrijver K. Listeriose Neuro-Meningee Associee a La Consommation De Creme Glacee. Med Mal Infect 1990. [DOI: 10.1016/s0399-077x(05)80159-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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