Evaluation of a new chromogenic agar for the detection of Listeria in food

Willis, Caroline; Baalham, T.; Greenwood, M.; Presland, F.

doi:10.1111/j.1365-2672.2006.02917.x

Cited by 19 publications

(18 citation statements)

References 12 publications

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“…The calculation of the isolation sensitivity of each medium was done via isolation results and by using a TP (true positive)/(TP + WN, wrong negative) × 100 formula (25,26). The results were evaluated with Pearson's chisquare test in SPSS 18.0.…”

Section: Methodsmentioning

confidence: 99%

Comparison of the isolation and inhibition abilities ofselective media used for Brucella spp. Isolation

Karagül¹,

İkiz²

2017

Turk J Vet Anim Sci

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The aim of this study was to compare and contrast the isolation ability of selective media developed for Brucella spp. isolation and their inhibition ability against contaminant microorganisms. Fifty-one field strains biotyped from abortion case samples and 25 Brucella spp. negative organ samples were used. Strain suspensions and organ suspensions were prepared separately. The turbidity of the strain suspensions was measured via spectrophotometer. The bacterial density of the strain suspensions was prepared in such a way that the suspensions would have different turbidity values. Inoculation into Farrell, Agrifood Research and Technology Center of Aragon, Jones & Morgan, and Modified Thayer Martin media was performed simultaneously from a dilution of each strain suspension and organ suspension. It was incubated in a 37 °C, 5%-10% CO 2 condition for 5-8 days. Brucella isolates were identified via a conventional biotyping method. The results of this study illustrate that selective media have isolation and cultivation ability for B. abortus biovar (bv) 3, B. abortus bv1, B. melitensis bv3, B. melitensis bv1, Rev1, and S-19 strains isolated from the field. There is more variation in the contaminant inhibition ability of the media compared to their isolation sensitivity. Farrell medium has 47 Brucella spp. isolations in 51 samples. It showed the highest performance with an isolation sensitivity of 92.1% and an inhibition ability of 80%. In this context, it might be suggested that researchers should initially use Farrell medium and, afterwards, use it simultaneously with another medium to be able to increase the isolation ability.

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Section: Methodsmentioning

confidence: 99%

Comparison of the isolation and inhibition abilities ofselective media used for Brucella spp. Isolation

Karagül¹,

İkiz²

2017

Turk J Vet Anim Sci

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“…The results suggest that soya lecithin is an appropriate alternative to phosphatidylinositol. Soya lecithin is a cheap and easily available product and could be used for the detection of PI-PLC and PC-PLC activity (22,32). In this study, LL medium contains soya lecithin for the differentiation of L. monocytogenes from other Listeria spp.…”

Section: Discussionmentioning

confidence: 99%

“…However, PALCAM, Oxford agar, and MOX, which use esculinase activity of Listeria spp., cannot differentiate L. monocytogenes from other Listeria spp. Also, several chromogenic media that use chromogenic compounds, such as 5-bromo-4-chloro-3-indoxyl-␤-Dglucopyranoside and L-␣-phosphatidylinositol, are expensive (22).…”

Section: Discussionmentioning

confidence: 99%

“…The sensitivity was calculated as the proportion of L. monocytogenes-positive samples correctly found to be positive (22). The confirmation rate was determined as the ratio of the number of confirmed L. monocytogenes colonies (C) to the number of total suspect colonies tested (S), expressed as (C/S) ϫ 100% (14).…”

Section: Stock Culturesmentioning

confidence: 99%

“…Chromogenic substrates have proven to be an efficient tool, utilizing specific enzymatic reactions of certain bacteria (2). However, chromogenic media can be expensive and may not be suitable for routine laboratory use (22). Also some Bacillus spp., especially Bacillus cereus, and Staphylococcus aureus are ␤-D-glucosidase, PI-PLC, and PC-PLC positive, and thus, they could grow on chromogenic media and produce colonies similar to those of L. monocytogenes (22,(26)(27)(28)(29)(30).…”

mentioning

confidence: 99%

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Development of a Novel Selective and Differential Medium for the Isolation of Listeria monocytogenes

Park

Chang

Ryu

et al. 2014

Appl Environ Microbiol

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A new medium (lecithin and levofloxacin [LL] medium) is described for the isolation of Listeria monocytogenes from food samples. LL medium includes lecithin from soybeans for the detection of phosphatidylinositol-specific phospholipase C (PI-PLC) and phosphatidylcholine-specific phospholipase C (PC-PLC) produced by L. monocytogenes. Levofloxacin is incorporated to inhibit the growth of microorganisms other than L. monocytogenes, especially Bacillus cereus, shown to possess PI-PLC and PC-PLC activities. L. monocyogenes produced white colonies with a halo on LL medium, whereas Listeria innocua appeared as white colonies without a halo. Levofloxacin at 0.20 mg/liter completely inhibited the growth of B. cereus, while the growth of L. monocytogenes was unaffected. In the second phase of the study, the sensitivity and the specificity of LL medium were compared to those of modified Oxford agar (MOX) and two chromogenic media (Brilliance Listeria agar and CHROMagar Listeria), using a total of 250 food samples. From 200 unspiked food samples, the specificity of LL medium (96.0%) was superior to that of MOX (72.0%) and similar to the specificities of Brilliance Listeria agar (96.5%) and CHROMagar Listeria (94.5%). From 50 spiked food samples, LL medium and CHROMagar Listeria represented the highest sensitivities (96.0%), followed by Brilliance Listeria agar (92.0%) and MOX (54.0%). Also, LL medium showed the highest confirmation rate (98.8%), followed by Brilliance Listeria agar (98.7%), CHROMagar Listeria (98.3%), and MOX (52.0%). On the basis of its good specificity and cost effectiveness, LL medium is useful for the isolation of L. monocytogenes from food samples.

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Biofilm Formation in Food Processing Environments is Still Poorly Understood and Controlled

2014

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The presence of undesirable biofilms on food processing contact surfaces may lead to: 1) transmission of diseases; 2) food spoilage; 3) shortened time between cleaning events; 4) contamination of product by nonstarter bacteria; 5) metal corrosion in pipelines and tanks; 6) reduced heat transfer efficacy or even obstruction of the heat equipment.Despite the significant problems caused by biofilms in the food industry, biofilm formation in these environments is still poorly understood and effective control of biofilms remains challenging. Although it is understood that cell attachment and biofilm formation are influenced by several factors, including type of strain, chemical-physical properties of the surface, temperature, growth media, and the presence of other microorganisms, some conflicting statements can be retrieved from the literature and there are no general trends yet that allow us to easily predict biofilm development. It is likely that still unexplored interaction of factors may be more critical than the effect of a single parameter.New alternative biofilm control strategies, such as biocontrol, use of enzymes and phages, and cell-to-cell communication interference, are now available that can reduce the use of chemical agents. In addition, as preventing biofilm formation is a more efficient strategy than controlling mature biofilm, the use of surface-modified materials have been suggested. These strategies may better reveal their beneficial potential when the ecological complexity of biofilms in food environments is addressed.

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Evaluation of a new chromogenic agar for the detection of Listeria in food

Cited by 19 publications

References 12 publications

Comparison of the isolation and inhibition abilities ofselective media used for Brucella spp. Isolation

Comparison of the isolation and inhibition abilities ofselective media used for Brucella spp. Isolation

Development of a Novel Selective and Differential Medium for the Isolation of Listeria monocytogenes

Biofilm Formation in Food Processing Environments is Still Poorly Understood and Controlled

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