Evaluation of BBL CHROMagar Listeria agar for the isolation and identification of Listeria monocytogenes from food and environmental samples

Hegde, Veena; León-Velarde, Carlos G.; Stam, C.; Jaykus, Lee‐Ann; Odumeru, Joseph A.

doi:10.1016/j.mimet.2006.06.011

Cited by 32 publications

(13 citation statements)

References 30 publications

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“…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%

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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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Section: Stock Culturesmentioning

confidence: 99%

“…PLC) (14,15,23,24). PI-PLC and PC-PLC, the major virulence factors, are only produced by pathogenic L. monocytogenes and Listeria ivanovii (15,25).…”

mentioning

confidence: 99%

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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“…(Aurora, Prakash, Prakash, Rawool, & Barbuddhe, 2008;Becker et al, 2006;Curtis & Lee, 1995;Hegde, Leon-Velarde, Stam, Jaykus, & Odumeru, 2007;Reissbrodt, 2004).…”

Section: Listeria Selective Plating Mediamentioning

confidence: 99%

Practical relevance of methodologies for detecting and tracing of Listeria monocytogenes in ready-to-eat foods and manufacture environments – A review

Zunabovic

Domig

Kneifel

2011

LWT - Food Science and Technology

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“…An aerobic plate count was performed on the homogenate from each coupon to determine the concentration of viable bacteria after each 24-h period. An aliquot of the cultures and any suspect colonies were plated on CHROMagar Listeria agar (Becton and Dickinson Co., Sparks, MD) to conWrm the continued presence and purity of Listeria [23].…”

Section: Biowlm Extraction and Measurementmentioning

confidence: 99%

Colorimetric assay for biofilms in wet processing conditions

Arnold

2008

J Ind Microbiol Biotechnol

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Controlling bacterial biofilms is necessary for food safety and industrial processing in clean room environments. Our goal was to develop a method to quantitatively measure biofilm produced by pathogens under wet poultry production and processing conditions. Stainless steel and glass coupons were incubated in aqueous media containing reduced nutrients and exposed to Listeria monocytogenes under static temperature and humidity conditions. Samples were measured separately by biofilm assay and viable cell density, and then confirmed by spectrophotometry and microscopy. The biofilm assay resulted in different t groupings from the cell density. The mean from the biofilm assay was 0.50, and the error% was 0.595. The mean of the log10 density (cfu/cm2) was 5.90, and the standard deviation ranged from 0.127 to 0.438 on 24 coupons. The typical sequence of biofilm development, followed by microscopy of biofilm grown on glass coupons, exhibited a change from dispersed single cells to an all-over pattern of clumps with few dispersed cells. L. monocytogenes formed biofilms on all of the substrata tested. Bacterial counts from planktonic cultures at 24, 48, 72, and 144 h confirmed that L. monocytogenes remained viable throughout the experiment and reached equilibrium between 6 and 24 h. The cell density log10/ml was 8.01, 8.03, 7.69, and 6.66, respectively; and the standard deviation ranged from 0.156 to 0.394. The data will be used to grow stable biofilms of Listeria spp. collected from the food processing environment for further study. This is the first use of the crystal violet assay for measurement of bacterial biofilms on stainless steel under these conditions. The methods tested are applicable to other bacteria and substrata.

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Evaluation of BBL CHROMagar Listeria agar for the isolation and identification of Listeria monocytogenes from food and environmental samples

Cited by 32 publications

References 30 publications

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

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

Practical relevance of methodologies for detecting and tracing of Listeria monocytogenes in ready-to-eat foods and manufacture environments – A review

Colorimetric assay for biofilms in wet processing conditions

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