Profiling of Recovery Efficiencies for Three Standard Protocols (FDA-BAM, ISO-11290, and Modified USDA) on Temperature-Injured Listeria monocytogenes

Lee, Hai Yen; Chai, Lay Ching; Pui, Chai Fung; Wong, Woan Chwen; Mustafa, Shuhaimi; Cheah, Yoke Kqueen; Issa, Zuraini Mat; Nishibuchi, Mitsuaki; Radu, Son

doi:10.4014/jmb.1012.12034

Cited by 4 publications

(3 citation statements)

References 33 publications

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“…The BLEB 48and 24-h enrichment procedures were the only methods with which all 21 Listeria strains grew to detectable levels. The data from this and previous studies in which growth in BLEB was evaluated (37,44,57) indicate that the BLEB enrichment procedure supports reliable growth of all Listeria species. Sheth et al (57) conducted a qualitative study with five Listeria species (the Listeria sensu stricto species excluding L. marthii) by comparing the FDA method with the USDA and ISO methods for detection of desiccation-stressed Listeria from environmental surfaces.…”

Section: Discussionsupporting

confidence: 65%

Assessment of Reference Method Selective Broth and Plating Media with 19 Listeria Species Highlights the Importance of Including Diverse Species in Listeria Method Evaluations

Carlin

Roof

Wiedmann

2022

Journal of Food Protection

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Reference methods developed for L. monocytogenes are commonly used for Listeria spp. detection. Improved method performance data are needed, since the genus Listeria has expanded from 6 to 26 species and now includes several Listeria sensu lato species, which can show phenotypes distinct from Listeria sensu stricto . Here, we evaluated growth of 19 Listeria spp., including 12 recently described sensu lato species, using the media specified by (i) the U.S. Food and Drug Administration (FDA) Bacteriological Analytical Manual , (ii) the U.S. Department of Agriculture (USDA) Microbiology Laboratory Guidebook , and (iii) the International Organization for Standardization (ISO). The FDA enrichment procedure allowed all species to grow to detectable levels (≥ 4 log 10 ), yielded the highest mean growth (7.58 log 10 ), and was the only procedure where no sensu lato species yielded significantly higher bacterial growth than a sensu stricto species. With the USDA or ISO enrichment procedures several sensu lato species yielded significantly higher bacterial growth than either L. seeligeri or L. ivanovii , suggesting that these two sensu stricto species could be outgrown by sensu lato species. On selective and differential agars, L. seeligeri, L. ivanovii, and L. grayi yielded atypical colony morphologies and/or showed inhibited growth (which may lead to incorrect classification of a sample as negative), while several newly described sensu lato species grew well and showed typical morphologies. Overall, our study shows that the ability to detect different Listeria spp. can be impacted by the specific broth and selective and differential agars used. Our data will aid with selection of media and detection methods for environmental Listeria monitoring programs and facilitate selection of methods that are most likely to detect the targeted Listeria groups (e.g., Listeria sensu stricto, which appear to be the most appropriate index organisms for the pathogen L. monocytogenes ).

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Section: Discussionsupporting

confidence: 65%

Assessment of Reference Method Selective Broth and Plating Media with 19 Listeria Species Highlights the Importance of Including Diverse Species in Listeria Method Evaluations

Carlin

Roof

Wiedmann

2022

Journal of Food Protection

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“…These cells are then revitalized by the ISO method, being then able to grow in laboratory media, as it happened in the majority of the herein analyzed samples. However, some cells may be also sublethally injured; therefore, the standard selective enrichment steps do not promote their recovery as efficiently as for the uninjured cells, producing negative results even when qualitative methods are applied (Lee et al, 2011). The discrepancy observed between MPN and ISO methods could then be attributed to the presence in some samples (n = 3) of damaged cells which did not grow (or were outgrown by other flora) in Half-Fraser broth incubated overnight (following the ISO method), but they were able to multiply when grown on Fraser broth for 48 h (as required by MPN).…”

Section: Discussionmentioning

confidence: 99%

Detection, identification, and typing of Listeria species from baled silages fed to dairy cows

Nucera

Grassi

Morra

et al. 2016

Journal of Dairy Science

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Anaerobiosis, critical for successful ensilage, constitutes a challenge in baled silages. The loss of complete anaerobiosis causes aerobic deterioration and silages undergo dry matter and nutrient losses, pathogen growth, and mycotoxin production. Silage may represent an ideal substrate for Listeria monocytogenes, a pathogen of primary concern in several cheeses. The aim of this research was to investigate the occurrence of Listeria in baled silage fed to cows producing milk for a protected designation of origin cheese, and to characterize isolates by repetitive sequence-based PCR. Listeria spp. were detected in 21 silages and L. monocytogenes in 6 out of 80 of the analyzed silages; 67% of positives were found in molded zones. Results of the PCR typing showed genotypic homogeneity: 72.9 and 78.8% similarity between strains of Listeria spp. (n = 56) and L. monocytogenes (n = 24), respectively. Identical profiles were recovered in molded and nonmolded areas, indicating that contamination may have occurred during production. The application of PCR allowed the unambiguous identification of Listeria isolated from baled silages, and repetitive sequence-based PCR allowed a rapid and effective typing of isolates. Results disclose the potential of the systematic typing of Listeria in primary production, which is needed for the understanding of its transmission pathways.

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“…Auto-mix tablets were added to one bag (mLRBA6) and the selective agents were manually added to two bags (mLRBM6 and mLRBS6) after 6 h, and the last bag was used as a nonselective control. Samples from each bag culture were taken at 12,14,16,18,22,24, and 48 h of incubation for serial dilution in BPB. Cell counts at each time point were obtained from duplicate plates of the dilution that was readable.…”

Section: Determination Of Percentage Of Injured Cells the Percentmentioning

confidence: 99%

Delivery of Selective Agents via Time-Delayed Release Tablets Improves Recovery of Listeria monocytogenes Injured by Acid and Nitrite

Nyarko

D’Amico

Mach

et al. 2014

Journal of Food Protection

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Listeria selective enrichment media are designed to enhance the isolation of the organism and increase the chances of detection. Drawbacks include the requirements for prolonged sample incubation (48 to 72 h) and manual addition of selective agents, which may be a source of contamination. Modified Listeria recovery broth (mLRB) is a proprietary enrichment medium formulated to facilitate the recovery of injured cells; its selective agents are incorporated into a format that allows delayed release until 6 h of incubation. We evaluated the change in cell populations over time for acid- and nitrite-injured Listeria monocytogenes in mLRB with the selective agents added manually at 0 h (mLRBS0) and 6 h (mLRBS6). Recovery of injured cells in mLRB plus time-delayed tablets (mLRBTD) was also compared with that in enrichment media recommended by the U.S. Department of Agriculture (University of Vermont broth), the U.S. Food and Drug Administration (buffered Listeria enrichment broth), and the International Organization for Standardization (demi-Fraser broth). Nitrite- or acid-injured Listeria at approximately 10 CFU/ml were inoculated into each broth medium, and Listeria populations were enumerated at various times from 12 to 48 h of incubation at 37°C. Analysis of variance revealed that acid-injured Listeria populations in mLRBS6 at 24 h were significantly higher (P < 0.05) than those in mLRBS0; however, the differences in populations on these two media were not significant for nitrite-injured cells. Cell populations of four strains of Listeria inoculated into mLRBTD were significantly higher at 24 h than when those strains were enriched in buffered Listeria enrichment broth, demi-Fraser broth, and University of Vermont broth. Comparison between artificially contaminated milk and meat samples with a four-strain cocktail of Listeria resulted in cell populations that were significantly higher (P < 0.05) at 24 h on mLRBTD for contaminated meat than on mLRB for contaminated milk. Delivery of selective agents via time-delayed release tablets into mLRB maximizes recovery of acid- and nitrite-injured Listeria and saves analyst time during food sample analysis.

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Profiling of Recovery Efficiencies for Three Standard Protocols (FDA-BAM, ISO-11290, and Modified USDA) on Temperature-Injured Listeria monocytogenes

Cited by 4 publications

References 33 publications

Assessment of Reference Method Selective Broth and Plating Media with 19 Listeria Species Highlights the Importance of Including Diverse Species in Listeria Method Evaluations

Assessment of Reference Method Selective Broth and Plating Media with 19 Listeria Species Highlights the Importance of Including Diverse Species in Listeria Method Evaluations

Detection, identification, and typing of Listeria species from baled silages fed to dairy cows

Delivery of Selective Agents via Time-Delayed Release Tablets Improves Recovery of Listeria monocytogenes Injured by Acid and Nitrite

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