Listeria monocytogenes in Irish Farmhouse cheese processing environments

Fox, Edward M.; Hunt, Karen A.; O'Brien, Martina; Jordan, Kieran

doi:10.1016/j.ijfoodmicro.2010.10.012

Cited by 92 publications

(79 citation statements)

References 39 publications

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“…This study identified 18 different randomly amplified polymorphic DNA (RAPD) profiles among the L. monocytogenes strains, and interestingly, one of these RAPD types was seen throughout the 12 months of the study. Similar evidence of persistent strains has subsequently been documented in other Irish food industries (8,12,13). Examples of an L. monocytogenes strain persisting as part of the microflora of a food-processing facility have been reported in other countries.…”

supporting

confidence: 74%

Physiological and Transcriptional Characterization of Persistent and Nonpersistent Listeria monocytogenes Isolates

Fox

Leonard

Jordan

2011

Appl Environ Microbiol

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114

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This study aimed to characterize physiological differences between persistent and presumed nonpersistent Listeria monocytogenes strains isolated at processing facilities and to investigate the molecular basis for this by transcriptomic sequencing. Full metabolic profiles of two strains, one persistent and one nonpersistent, were initially screened using Biolog's Phenotype MicroArray (PM) technology. Based on these results, in which major differences from selected antimicrobial agents were detected, another persistent strain and two nonpersistent strains were characterized using two antimicrobial PMs. Resistance to quaternary ammonium compounds (QACs) was shown to be higher among persistent strains. Growth of persistent and nonpersistent strains in various concentrations of the QACs benzethonium chloride (BZT) and cetylpyridinium chloride (CPC) was determined. Transcriptomic sequencing of a persistent and a presumed nonpersistent strain was performed to compare gene expression among these strains in the presence and absence of BZT. Two strains, designated "frequent persisters" because they were the most frequently isolated at the processing facility, showed overall higher resistance to QACs. Transcriptome analysis showed that BZT induced a complex peptidoglycan (PG) biosynthesis response, which may play a key role in BZT resistance. Comparison of persistent and nonpersistent strains indicated that transcription of many genes was upregulated among persistent strains. This included three gene operons: pdu, cob-cbi, and eut. These genes may play a role in the persistence of L. monocytogenes outside the human host.Listeria monocytogenes is a human food-borne pathogen that causes listeriosis in humans. Because infection is primarily food borne, control of the organism in food-processing environments, including dairy food production facilities, is important. There are many studies detailing the occurrence of L. monocytogenes in food-processing facilities (18,22,25,28). In order to better understand the ecology and transmission of L. monocytogenes strains through the processing facility, however, techniques such as molecular strain typing are necessary. Such studies not only play a crucial role in determining possible transmission vectors, they provide insights into the persistence of certain strains at the facility itself. This is of critical importance to the manufacturer, as strains that can successfully persist at the production facility have an increased chance of cross-contamination of the product and thus lead to an increased likelihood of product recall or human infection. A study published in 1995 by Lawrence and Gilmour (20) characterized strains isolated over a 12-month period at a poultryprocessing plant located in Ireland. This study identified 18 different randomly amplified polymorphic DNA (RAPD) profiles among the L. monocytogenes strains, and interestingly, one of these RAPD types was seen throughout the 12 months of the study. Similar evidence of persistent strains has subsequently been documented in o...

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supporting

confidence: 74%

Physiological and Transcriptional Characterization of Persistent and Nonpersistent Listeria monocytogenes Isolates

Fox

Leonard

Jordan

2011

Appl Environ Microbiol

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114

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“…This observation also agrees with that of VardarÜnlü et al, (1998), Sağun et al, (2001), Aygun and Pehlivanlar, (2006), Taşçı et al, (2010), Abay et al, (2012), and Durmaz et al, (2015), who found 4% in Sivas, 1.2% in Van, 0% in Antakya, 2.4% in Burdur, 0% in Kayseri, and 2.2% in Şanlıurfa and Adıyaman, respectively. In other countries, as opposed to our study, the reported isolation rates of L. monocytogenes from raw milk samples were 16.7% in Brazil (Silva et al, 2003), 6.5% in United States (van Kessel et al, 2004), 4% in Iran (Jami et al, 2010), 22% in Ethiopia (Gebretsadik et al, 2011), 6.3% in Ireland (Fox et al, 2011), 41.6% in Syria (Al-Mariri et al, 2013), 21.7% in Malaysia (Jamali et al, 2013), and 16.6% in India (Nayak et al, 2015). Contamination rates of L. monocytogenes are affected seasonal variations (Taşçı et al, 2010).…”

Section: Discussioncontrasting

confidence: 85%

Prevalence and Characterization of Listeria Species from Raw Milk and Dairy Products from Çanakkale Province

Şanlibaba

Tezel

2018

Turkish JAF Sci.Tech.

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The objective of this study was to determine the prevalence of Listeria species, specifically Listeria monocytogenes, in raw milk, pasteurized milk, white cheese, and homemade cheese. A total of 200 food samples were collected and analyzed to examine the presence of Listeria spp. The EN ISO 11290-1 method was used for isolation of Listeria. API Listeria test kit was used for biochemically characterization. Listeria spp. were isolated in 25 of the 200 samples (12.5%). The largest number of Listeria spp. was detected in homemade cheese (24%), followed by raw milk (18%), and white cheese (8%). Listeria spp. were not isolated from the pasteurized milk. The most common species isolated were Listeria innocua (5.5%); the remaining Listeria isolates were Listeria ivanovi (3.5%), Listeria welshimeri (3%), and Listeria monocytogenes (0.5%). Listeria monocytogenes was detected in only raw milk.

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“…In Ireland the incidence was 3% (Rea et al 1992), and 6% (Fox et al 2011a), in Northern Ireland 8.8% (Harvey and Gilmour 1993), in the USA 19.7% (Latorre et al 2009), 1% (Waak et al 2002), 4.1% (Rohrbach et al 1992) and 0% (D'Amico and Donnelly 2010). Other reported incidences include 1.7% in Iran years, it is difficult to compare these reported incidences.…”

Section: Occurrence Of L Monocytogenes In Milkmentioning

confidence: 97%

“…monocytogenes is ubiquitous in the environment (Fox et al 2011a) and has been isolated from a wide variety of ready-to-eat foods, not only from dairy products but also from meat and fish products, among others (Lianou and Sofos 2007). Its occurrence in the environment may pose the threat of L. monocytogenes transfer from the environment to the milk product, even though the routes of contamination are not always clearly identified.…”

Section: Monocytogenes In the Processing Environmentmentioning

confidence: 99%