Improved detection of Listeria monocytogenes in soft mould-ripened cheese

Johansson, Tuula; Ahola-Luttila, H.; Pirhonen, Tuula; Taimisto, Anna-Maija; Haario, Heikki; Lainé, Muriel; Salkinoja‐Salonen, Mirja

doi:10.1046/j.1365-2672.2000.01030.x

Cited by 18 publications

(4 citation statements)

References 19 publications

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“…The medium LMBA presented for all the samples a higher sensitivity for detection of L. monocytogenes than the media recommended by ISO (Anonymous, 1996a) ( Table 2). The lower sensitivity observed on the media PALCAM and Oxford has already been reported by Johansson (1998) and Johansson et al (2000) and is possibly related with the concentration of LiCl (15 g/l) which is higher than the concentration of this compound in LMBA (10 g/l), or the absence of acri¯avine and other 3 (6.1%) 1 (2.0%) 1 (2.0%) 3 (6.1%) Fresh cheese 15 1 (6.7%) 0 (0.0%) 0 (0.0%) 1 (6.7%) Fresh ®sh 23 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) Fresh meats 8 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) Other 13 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) Total 445 29 (6.5%) 12 (2.7%) 12 (2.7%) 28 (6.3%) selective agents that are present in PALCAM and Oxford but not in LMBA. It is well known that microorganisms in foods are often injured so that they become sensitive to the presence of selective agents present in media normally used in their isolation (Mackey, 1999).…”

Section: Methodssupporting

confidence: 57%

Comparison of Oxford Agar, PALCAM and Listeria monocytogenes Blood Agar for the recovery of L. monocytogenes from foods and environmental samples

et al. 2001

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This work had as the main objective a comparison between Listeria monocytogenes Blood Agar (LMBA) and the conventional selective agar media, Oxford and PALCAM, relative to its ecacy in the detection of L. monocytogenes in naturally contaminated food and environmental samples. 173 environmental samples and 272 samples of foods were analysed. A higher sensitivity for detection of L. monocytogenes was veri®ed for LMBA than for PALCAM and Oxford. In LMBA L. monocytogenes could be distinguished from other Listeria spp. by detection of hemolysis. In Oxford and PALCAM this distinction was not possible. The higher growth rate of L. innocua cf. L. monocytogenes in selective liquid media could result in a high number of false negatives (nondetection of the target organism on plates, although its presence was observed by other tests, eg. mini-VIDAS LMO). The need for speci®c media for the detection of L. monocytogenes in food was con®rmed. LMBA could be an alternative medium to use together with PALCAM or Oxford. Ó

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Section: Methodssupporting

confidence: 57%

Comparison of Oxford Agar, PALCAM and Listeria monocytogenes Blood Agar for the recovery of L. monocytogenes from foods and environmental samples

et al. 2001

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“…Furthermore, L. innocua grows faster than L. monocytogenes in selective enrichment broths. This may lead to false negative results using conventional techniques (Petran and Swanson 1993; Johansson et al . 2000).…”

Section: Discussionmentioning

confidence: 99%

GENEGEN TECHNOLOGY FOR DETECTION OF SALMONELLA SPP. AND GENUS LISTERIA/LISTERIA MONOCYTOGENES IN CHICKEN SAMPLES

Vollenhofer‐Schrumpf¹,

Buresch²,

Unger³

et al. 2006

Rapid Methods Automation Mic

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Performances of two commercial test systems for the detection of Salmonella spp. and genus Listeria/Listeria monocytogenes (GeneGen Salmonella Detection Kit and GeneGen Listeria Detection Kit, respectively) were tested. The technology combines multiplex polymerase chain reaction with a shortened, simplified hybridization protocol using test strips. In specificity tests using a collection of over 80 bacterial strains representing 22 genera, no false positive or false negative results were observed. The limit of detection was 100 and 10 genome copies for the Salmonella and Listeria assays, respectively. The kits were used for both analyses of spiked and naturally contaminated chicken samples, and their performances were compared with standard methods. An amount of 1–10 cfu/25 g of the respective pathogen added could be detected. Results achieved with the GeneGen Salmonella Detection Kit were in 100% concordance with the microbiological protocol. The GeneGen Listeria Detection Kit proved to be more sensitive than the standard method in the spiking experiments, as well as for chicken samples naturally contaminated with both Listeria innocua and L. monocytogenes. The kits provided a time saving of several days compared to conventional methods (30‐h detection time for Salmonella, 30–54 h for Listeria). The protocol is simple and does not require any high‐tech equipment for evaluation or documentation after DNA amplification. Hybridization can be carried out at ambient temperature, and results are evaluated with the unaided eye. Thus, these kits could be a valuable tool for the screening of food samples and confirmation of suspect colonies, especially in modestly equipped laboratories.

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“…2001). Furthermore, in selective enrichment broths, L. innocua grows faster than L. monocytogenes (Petran and Swanson 1993; Johansson et al. 2000) which may lead to false‐negative results for L. monocytogenes .…”

Section: Discussionmentioning

confidence: 99%

DETECTION OF SALMONELLA SPP., ESCHERICHIA COLI O157, LISTERIA MONOCYTOGENES AND CAMPYLOBACTER SPP. IN CHICKEN SAMPLES BY MULTIPLEX POLYMERASE CHAIN REACTION AND HYBRIDIZATION USING THE GENEGEN MAJOR FOOD PATHOGENS DETECTION KIT

Vollenhofer‐Schrumpf¹,

Buresch²,

Unger³

et al. 2005

Rapid Methods Automation Mic

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We have applied an innovative commercial test system (the GeneGen Major Food Pathogens [MFP] Detection Kit) to detect four of the more important pathogenic microorganisms in food, Salmonella spp., Escherichia coli O157, Listeria monocytogenes and Campylobacter spp. by using multiplex polymerase chain reaction (PCR) combined with a shortened, simplified hybridization protocol on test strips. Testing 129 strains representing 23 different genera yielded no false‐positive or false‐negative results, and the limit of detection was 100 genome copies of each organism per multiplex PCR using purified genomic DNA. The kit was used for both analyses of chicken samples artificially contaminated with different numbers of the pathogens and of naturally contaminated samples. The results were compared with those obtained with standard microbiological techniques. Both methods yielded the same results in spiking experiments, detecting 1–10 cfu/25 g of the respective pathogen added. It was possible to verify the presence of all four pathogens simultaneously in one assay. The GeneGen MFP Detection Kit saves at least 2–4 days compared with standard methods. The protocol is easy to perform, and there is no need for any additional costly and sophisticated equipment, except for a thermocycler, because hybridization is carried out at ambient temperature and the results can be evaluated with the unaided eye. This enables the assay to be performed in relatively modestly equipped laboratories for both DNA‐based screening of food samples and/or confirmation of suspect colonies.

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Improved detection of Listeria monocytogenes in soft mould-ripened cheese

Cited by 18 publications

References 19 publications

Comparison of Oxford Agar, PALCAM and Listeria monocytogenes Blood Agar for the recovery of L. monocytogenes from foods and environmental samples

Comparison of Oxford Agar, PALCAM and Listeria monocytogenes Blood Agar for the recovery of L. monocytogenes from foods and environmental samples

GENEGEN TECHNOLOGY FOR DETECTION OF SALMONELLA SPP. AND GENUS LISTERIA/LISTERIA MONOCYTOGENES IN CHICKEN SAMPLES

DETECTION OF SALMONELLA SPP., ESCHERICHIA COLI O157, LISTERIA MONOCYTOGENES AND CAMPYLOBACTER SPP. IN CHICKEN SAMPLES BY MULTIPLEX POLYMERASE CHAIN REACTION AND HYBRIDIZATION USING THE GENEGEN MAJOR FOOD PATHOGENS DETECTION KIT

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