An insight into the isolation, enumeration, and molecular detection of Listeria monocytogenes in food

Abstract

Listeria monocytogenes, a foodborne pathogen that can cause listeriosis through the consumption of food contaminated with this pathogen. The ability of L. monocytogenes to survive in extreme conditions and cause food contaminations have become a major concern. Hence, routine microbiological food testing is necessary to prevent food contamination and outbreaks of foodborne illness. This review provides insight into the methods for cultural detection, enumeration, and molecular identification of L. monocytogenes in various food samples. There are a number of enrichment and plating media that can be used for the isolation of L. monocytogenes from food samples. Enrichment media such as buffered Listeria enrichment broth, Fraser broth, and University of Vermont Medium (UVM) Listeria enrichment broth are recommended by regulatory agencies such as Food and Drug Administration-bacteriological and analytical method (FDA-BAM), US Department of Agriculture-Food and Safety (USDA-FSIS), and International Organization for Standardization (ISO). Many plating media are available for the isolation of L. monocytogenes, for instance, polymyxin acriflavin lithium-chloride ceftazidime aesculin mannitol, Oxford, and other chromogenic media. Besides, reference methods like FDA-BAM, ISO 11290 method, and USDA-FSIS method are usually applied for the cultural detection or enumeration of L. monocytogenes. most probable number technique is applied for the enumeration of L. monocytogenes in the case of low level contamination. Molecular methods including polymerase chain reaction, multiplex polymerase chain reaction, real-time/quantitative polymerase chain reaction, nucleic acid sequence-based amplification, loop-mediated isothermal amplification, DNA microarray, and next generation sequencing technology for the detection and identification of L. monocytogenes are discussed in this review. Overall, molecular methods are rapid, sensitive, specific, time- and labor-saving. In future, there are chances for the development of new techniques for the detection and identification of foodborne with improved features.

Advances and Challenges in Viability Detection of Foodborne Pathogens

“…Listeria monocytogenes is one the most habitually investigated foodborne pathogens, whereas the L. monocytogenes outbreaks had the highest proportion of hospitalized cases as well as the highest proportion of deaths registered in the European Union (Anonymous, 2011; Law et al, 2015a). Flekna et al (2007b) combined EMA with qPCR to detect viable cells of C. jejuni and L. monocytogenes .…”

Assessment of Listeria monocytogenes in pet food

“…Cultures which do not turn black can be considered free of Listeria spp., and further analysis may be unnecessary. However, potential negative results with Fraser broth can occur and as a result, it is advised to plate all cultures for further analysis [6,13]. In this study, the result shown in Fraser broth was further confirmed using PCR.…”

Meat and fiber intake and interaction with pattern recognition receptors (TLR1, TLR2, TLR4, and TLR10) in relation to colorectal cancer in a Danish prospective, case-cohort study

“…Bacterial cell-surface lipopolysaccharides are ligands for TLR1 activation (48), whereas TLR10 has been suggested as a key mediator of Listeria monocytogenes-induced inflammation (49). L. monocytogenes has become a major foodborne pathogen that can be found in meat and processed foods due to its ability to survive the most common food-processing conditions such as extreme pH, high salt concentration, low water activity, and refrigeration temperatures (50). In particular, L. monocytogenes has been found in high percentages of ready-to-eat processed meat products (51-53).…”