Development of a propidium monoazide treatment combined with loop-mediated isothermal amplification (PMA-LAMP) assay for rapid detection of viableListeria monocytogenes

Development of a Novel Phagomagnetic-Assisted Isothermal DNA Amplification System for Endpoint Electrochemical Detection of Listeria monocytogenes

The hitherto implemented Listeria monocytogenes detection techniques are cumbersome or require expensive non-portable instrumentation, hindering their transposition into on-time surveillance systems. The current work proposes a novel integrated system resorting to loop-mediated isothermal amplification (LAMP), assisted by a bacteriophage P100-magnetic platform, coupled to an endpoint electrochemical technique, towards L. monocytogenes expeditious detection. Molybdophosphate-based optimization of the bacterial phagomagnetic separation protocol allowed the determination of the optimal parameters for its execution (pH 7, 25 °C, 32 µg of magnetic particles; 60.6% of specific capture efficiency). The novel LAMP method targeting prfA was highly specific, accomplishing 100% inclusivity (for 61 L. monocytogenes strains) and 100% exclusivity (towards 42 non-target Gram-positive and Gram-negative bacteria). As a proof-of-concept, the developed scheme was successfully validated in pasteurized milk spiked with L. monocytogenes. The phagomagnetic-based approach succeeded in the selective bacterial capture and ensuing lysis, triggering Listeria DNA leakage, which was efficiently LAMP amplified. Methylene blue-based electrochemical detection of LAMP amplicons was accomplished in 20 min with remarkable analytical sensitivity (1 CFU mL^-1). Hence, the combined system presented an outstanding performance and robustness, providing a 2.5 h-swift, portable, cost-efficient detection scheme for decentralized on-field application.

A novel ADA-coated UCNPs@NB sensing platform combined with nucleic acid amplification for rapid detection of Escherichia coli

In this study, we reported a novel sensing platform based on fluorescence quenching composed of alendronic acid (ADA) coated upconversion nanoparticles (UCNPs) and Nile Blue (NB) combined with polymerase chain reaction (PCR) for rapid, sensitive, and specific detection of Escherichia coli (E. coli). As a fluorescence acceptor, NB has a broad absorption band and can quench upconversion fluorescence intensity at 544 nm and 658 nm based on IFE. PCR is a double-stranded DNA (dsDNA) amplification technique with high specificity. The NB-dsDNA complex can be formed by intercalation of NB between base pairs and groove of dsDNA, leading to upconversion fluorescence recovery. The ADA-coated UCNPs@NB sensing platform achieved to detect E. coli in 1.5 h, with a lower limit of detection (33 CFU mL^-1). In addition, the sensitivity of the ADA@UCNPs-NB fluorescence sensor under different PCR cycle numbers was discussed. The results showed that the proposed sensor could effectively shorten the assay time (1.0 h) while maintaining excellent sensitivity. This study demonstrated a rapid and sensitive analytical method for detecting E. coli in chicken, providing a reference for constructing PCR fluorescence sensors.

Quantitative Detection of Viable but Nonculturable Cronobacter sakazakii Using Photosensitive Nucleic Acid Dye PMA Combined with Isothermal Amplification LAMP in Raw Milk

An accurate method that rapidly detects the number of viable but nonculturable (VBNC) Cronobacter sakazakii was developed by combining propidium bromide with quantitative LAMP (PMA-QLAMP). The gyrB gene was the target for primers design. The optimal PMA treatment conditions were determined to eliminate the DNA amplification of 10⁸ CFU/mL of dead C. sakazakii without affecting any viable C. sakazakii DNA amplification. Compared with the DNA of 24 strains of common non-C. sakazakii strains found in raw milk and dairy products, the DNA of only six C. sakazakii strains from different sources was amplified using PMA-QLAMP. The ability of PMA-QLAMP to quantitatively detect non-dead C. sakazakii in a 10% powdered infant formula (PIF) solution was limited to 4.3 × 10² CFU/mL and above concentrations. Pasteurizing 10⁶ CFU/mL viable C. sakazakii yielded the maximum ratio of the VBNC C. sakazakii. PMA-QLAMP-based detection indicated that, although approximately 13% of 60 samples were positive for viable C. sakazakii, the C. sakazakii titers in these positive samples were low, and none entered the VBNC state under pasteurization. PMA-QLAMP showed potential as a specific and reliable method for detecting VBNC-C. sakazakii in pasteurized raw milk, thereby providing an early warning system that indicates potential contamination of PIF.

Listeria monocytogenes in foods-From culture identification to whole-genome characteristics

Listeria monocytogenes is an important foodborne pathogen, which is able to persist in the food production environments. The presence of these bacteria in different niches makes them a potential threat for public health. In the present review, the current information on the classical and alternative methods used for isolation and identification of L. monocytogenes in food have been described. Although these techniques are usually simple, standardized, inexpensive, and are routinely used in many food testing laboratories, several alternative molecular-based approaches for the bacteria detection in food and food production environments have been developed. They are characterized by the high sample throughput, a short time of analysis, and cost-effectiveness. However, these methods are important for the routine testing toward the presence and number of L. monocytogenes, but are not suitable for characteristics and typing of the bacterial isolates, which are crucial in the study of listeriosis infections. For these purposes, novel approaches, with a high discriminatory power to genetically distinguish the strains during epidemiological studies, have been developed, e.g., whole-genome sequence-based techniques such as NGS which provide an opportunity to perform comparison between strains of the same species. In the present review, we have shown a short description of the principles of microbiological, alternative, and modern methods of detection of L. monocytogenes in foods and characterization of the isolates for epidemiological purposes. According to our knowledge, similar comprehensive papers on such subject have not been recently published, and we hope that the current review may be interesting for research communities.

Reverse Transcription Loop-Mediated Isothermal Amplification Assay with High Sensitivity to Rapid Detection of Viable Salmonella in Foods

Background: Salmonella is one of the main foodborne bacterial pathogens, causing diseases and death. The study used reverse transcription loop-mediated isothermal amplification (RT-LAMP) to detect Salmonella. Objectives: To design six primers and detect Salmonella using RT-LAMP to facilitate the rapid detection of pathogenic bacteria in food. Methods: We designed six primers based on the gene coding sequences of inv A, specific to Salmonella. Each reaction solution contained 6.0 mM MgSO4, 1 M betaine, 1.6 mM dNTPs, 160 U/mL Bst DNA polymerase, 0.2 μM of both external primers, 0.8 μM of both internal primers, and 0.2 μM of both loop primers. The reaction temperature was 65°C. Results: Our amplified products were separated by 2% agarose gel electrophoresis. The detection limit was 10 CFU per reaction. Conclusions: RT-LAMP exhibited the same accuracy as the GB assay in detecting Salmonella in foods. RT-LAMP was highly specific and sensitive; hence, it may serve as an effective tool in detecting Salmonella.

Quantitative and specific detection of viable pathogens on a portable microfluidic chip system by combining improved propidium monoazide (PMAxx) and loop-mediated isothermal amplification (LAMP)

An accurate and specific detection of viable Candida albicans (C. albicans) in vaginal discharge is crucial for the diagnosis of vulvovaginal candidiasis (VVC) and assessment of antifungal effects. In this study, improved propidium monoazide (PMAxx) and loop-mediated isothermal amplification (LAMP) were used for the first time to distinguish between viable and dead C. albicans. A portable microfluidic chip system was developed to detect multiple viable pathogens in parallel. The consumption of samples and reagents in per reaction cell were only 0.94 μL, less than 1/25 of the conventional 25 μL Eppendorf tubular test method, both significantly reducing testing cost and greatly simplifying the detection of multiple viable pathogens. The concentration of PMAxx was optimized against C. albicans at 4.0 log CFU mL^-1 to 5.0 log CFU mL^-1, and 1 μM PMAxx was proven to be suitable for the detection of C. albicans in clinical samples. When testing mixtures containing different ratios of viable to dead C. albicans, PMAxx-LAMP could circumvent the signal arising from dead cells and, therefore, reflected the abundance of viable cells precisely. Furthermore, the suitability of this technique to evaluate the effects of antifungal agents, including clotrimazole, miconazole, and tioconazole, was assessed. Finally, the viability of Escherichia coli (E. coli) and C. albicans were detected on the portable microfluidic chip system. PMAxx-LAMP based portable microfluidic chip system was determined to be a feasible technique for assessing the viability of multiple pathogens in gynecology and might provide insights into new VVC treatment strategies.

Gaps in the assortment of rapid assays for microorganisms of interest to the dairy industry

This review presents the results of a study into the offering of rapid microbial detection assays to the Irish dairy industry. At the outset, a consultation process was undertaken whereby key stakeholders were asked to compile a list of the key microorganisms of interest to the sector. The resultant list comprises 19 organisms/groups of organisms divided into five categories: single pathogenic species (Cronobacter sakazakii, Escherichia coli and Listeria monocytogenes); genera containing pathogenic species (Bacillus, Clostridium, Listeria, Salmonella; Staphylococcus); broad taxonomic groupings (Coliforms, Enterobacteriaceae, fecal Streptococci, sulfite reducing bacteria/sulfite reducing Clostridia [SRBs/SRCs], yeasts and molds); organisms displaying certain growth preferences or resistance as regards temperature (endospores, psychrotrophs, thermodurics, thermophiles); indicators of quality (total plate count, Pseudomonas spp.). A survey of the rapid assays commercially available for the 19 organisms/groups of organisms was conducted. A wide disparity between the number of rapid tests available was found. Four categories were used to summarize the availability of rapid assays per organism/group of organisms: high coverage (>15 assays available); medium coverage (5-15 assays available); low coverage (<5 assays available); no coverage (0 assays available). Generally, species or genera containing pathogens, whose presence is regulated-for, tend to have a good selection of commercially available rapid assays for their detection, whereas groups composed of heterogenous or even undefined genera of mainly spoilage organisms tend to be "low coverage" or "no coverage." Organisms/groups of organisms with "low coverage" by rapid assays include: Clostridium spp.; fecal Streptococci; and Pseudomonas spp. Those with "no coverage" by rapid assays include: endospores; psychrotrophs; SRB/SRCs; thermodurics; and thermophiles. An important question is: why have manufacturers of rapid microbiological assays failed to respond to the necessity for rapid methods for these organisms/groups of organisms? The review offers explanations, ranging from the technical difficulty involved in detecting as broad a group as the thermodurics, which covers the spores of multiple sporeforming genera as well at least six genera of mesophilic nonsporeformers, to the taxonomically controversial issue as to what constitutes a fecal Streptococcus or SRBs/SRCs. We review two problematic areas for assay developers: validation/certification and the nature of dairy food matrices. Development and implementation of rapid alternative test methods for the dairy industry is influenced by regulations relating to both the microbiological quality standards and the criteria alternative methods must meet to qualify as acceptable test methods. However, the gap between the certification of developer's test systems as valid alternative methods in only a handful of representative matrices, and the requirement of dairy industries to verify the performance of alternative test systems in an extensive and diverse range of dairy matrices needs to be bridged before alternative methods can be widely accepted and adopted in the dairy industry. This study concludes that many important dairy matrices have effectively been ignored by assay developers.

Recent Progress of Nanozymes in the Detection of Pathogenic Microorganisms

Infectious diseases are among the world's principal health problems. It is crucial to develop rapid, accurate and cost-effective methods for the detection of pathogenic microorganisms. Recently, considerable progress has been achieved in the field of inorganic enzyme mimics (nanozymes). Compared with natural enzymes, nanozymes have higher stability and lower cost. More interestingly, their properties can be designed for various demands. Herein, we introduce the latest research progress on the detection of pathogenic microorganisms by using various nanozymes. We also discuss the current challenges of nanozymes in biosensing and provide some strategies to overcome these barriers.

Reverse transcription – loop-mediated isothermal amplification assay for the rapid detection of pathogenic Listeria monocytogenes in meat products

This study reports the use of reverse transcription – loop-mediated isothermal amplification (RT–LAMP) to detect Listeria monocytogenes in meat. The assay was designed to target the iap gene of L. monocytogenes, to which four primers, recognizing six distinct iap sites, were designed. We optimized the RT–LAMP conditions and established the following optimal systems: 60 min, 63 °C, 2.0 mmol/L MgSO4, 1.0 mol/L betaine, 2.0 mmol/L dNTPs, 320 U/mL Bst DNA polymerase, 0.4 μmol/L outer primers, and 0.8 μmol/L inner primers. The RT–LAMP amplification products were identified by a visible white Mg2P2O7 precipitate or electrophoresis on a 2% agarose gel. RT–LAMP has a sensitivity of 7.3 × 101 CFU/mL, which is 2-fold higher than that of LAMP. When commercially available raw meat samples (including beef, pork, mutton, and rabbit) were analyzed simultaneously with RT–LAMP and the Chinese National Standard GB 4789.30-2016, their abilities to detect L. monocytogenes were the same. Samples containing L. monocytogenes killed by 15 psi at 121 °C for 15 min were used to confirm the specificity of RT–LAMP for live microorganisms. Thus, we used RT–LAMP to efficiently detect L. monocytogenes in meat products.

Development of a duplex lateral flow dipstick test for the detection and differentiation of Listeria spp. and Listeria monocytogenes in meat products based on loop-mediated isothermal amplification

Listeria spp. are a group of gram-positive bacteria consisting of 20 species. Among them, Listeria monocytogenes is one of the major species that infects humans since it contaminates raw fruits, vegetables, and many others food products. The conventional methods for the detection of Listeria spp. and L. monocytogenes are time-consuming, taking 5-7 days. Herein, a duplex lateral flow dipstick (DLFD) test combined with loop-mediated isothermal amplification (LAMP) was developed for the identification of Listeria spp. and L. monocytogenes within approximately 45 min with the optimized LAMP reaction times at 63 °C. Under the optimized conditions, the method detection limits (MDL) with reference to genomic DNA and pure culture were 900 femtograms (fg) and 20 cfu/mL, respectively. The LAMP-DLFD showed no cross-reactivity with eighteen - other pathogenic bacteria such as Salmonella spp., Staphylococcus aureus, Escherichia coli, Campylobacter coli, C. jejuni, Enterococcus faecalis, Vibrio cholerae, V. parahaemolyticus, Pseudomonas aeruginosa, Shigella dysenteriae, S. flexneri, Bacillus cereus, Lactobacillus acidophilus, L. casei and Pediococcus pentosaceus. Among 100 samples of food products, LAMP-DLFD demonstrated 100% accuracy when compared to other standard detection methods, such as ISO11290-1, enzyme-linked fluorescent assay (ELFA) technology (VIDAS) and PCR. In conclusion, LAMP-DLFD proved to be highly specific and sensitive assays for screening detection of Listeria spp. and L. monocytogenes.

Discrimination of viable and dead Vibrio parahaemolyticus subjected to low temperatures using Propidium Monoazide - Quantitative loop mediated isothermal amplification (PMA-qLAMP) and PMA-qPCR

The aim of this study was to determine the effect of cold (4 °C) and subzero (-18 °C, -45 °C) temperatures on the occurrence time of membrane damage to provide Propidium Monoazide (PMA) penetration of Vibrio parahaemolyticus inoculated to the sea bass. Direct plate counting (DPC) and PMA-based quantitative loop-mediated isothermal amplification (qLAMP) and qPCR was utilized for discrimination of dead and live bacteria on the designated storage days (1, 3, 7, and 14). The optimum amount of PMA was 50 μM for inhibition of amplification derived from dead cells in spiked samples. The number of live V. parahaemolyticus was detectable at the end of the 14. day using PMA-qLAMP and PMA-qPCR at all the temperatures. On the 7th day, culturability has lost at any of the storage temperatures and DPCs at -18 °C and -45 °C revealed a difference of about 1 log₁₀ CFU/ml between 1st and 3rd days. The same difference was also observed in PMA-qLAMP and PMA-qPCR on the same days (0.59-0.95 log₁₀ CFU/ml). Subzero temperatures have the highest rate of viability while causing the fastest decrease in culturability in sample groups as a result of the higher level of transition to VBNC state. qLAMP and qPCR methods in the PMA-treated and nontreated groups on the storage days at all temperatures gave similar results (p > 0.05).

Genetic Analysis of the Listeria Pathogenicity Island 1 of Listeria monocytogenes 1/2a and 4b Isolates

The aim of the present study was to apply descriptive, phylogenetic, recombination, and selection analyses on alignments of the Listeria Pathogenicity Island 1 (LIPI-1) of 1/2a and 4b Listeria monocytogenes isolates of different origin in order to gain insights into the evolution of this virulence gene cluster. For that purpose, a total of 19 L. monocytogenes isolates (9 meat isolates, serotype 1/2a; 5 meat isolates, serotype 4b; 5 strawberry isolates, serotype 4b) that have been previously separated at strain level were subjected to sequencing of their LIPI-1. Descriptive analysis revealed extensive nucleotide diversity mostly in the intragenic regions. The actA gene of 1/2a and 4b meat isolates and the hly gene of the 4b strawberry isolates exhibited the higher diversity; limited diversity was observed in prfA and plcA genes of the 4b isolates and mpl gene of the 1/2a isolates. Phylogenetic analysis of the complete island resulted in two major clusters that were consistent with serotype assignment of the isolates. Moreover, effective discrimination between serotypes was obtained by plcA, plcB, mpl, actA and the intergenic regions plcA-prfA and plcA-hly. In all cases but plcB and plcA-prfA 4b isolates were also differentiated according to their source of isolation as well. Selection analysis revealed that the island consisted of randomly evolving DNA with the exception of prfA gene of 1/2a isolates and actA gene of 4b meat isolates for which purifying selection or population expansion was indicated. Finally, no statistically significant evidence for recombination has been observed.

Biotin-exposure-based immunomagnetic separation coupled with nucleic acid lateral flow biosensor for visibly detecting viable Listeria monocytogenes

Infectious diseases caused by Listeria monocytogenes pose a great threat to public health worldwide. Therefore, a rapid and efficient method for L. monocytogenes detection is needed. In this study, a biotin-exposure-based immunomagnetic separation (IMS) method was developed. That is, biotinylated antibody was first targeted to L. monocytogenes. Then, streptavidin-functionalized magnetic nanoparticles were added and anchored onto L. monocytogenes cells indirectly through the strong noncovalent interaction between streptavidin and biotin. Biotin-exposure-based IMS exhibited an excellent capability to enrich L. monocytogenes. Specifically, more than 90% of L. monocytogenes was captured when the bacterial concentration was lower than 10⁴ colony-forming units (CFU)/mL. Importantly, the antibody dosage was reduced by 10 times of that in our previous study, which used antibody direct-conjugated magnetic nanoparticles. Propidium monoazide (PMA) treatment prior to PCR amplification could eliminate the false-positive results from dead bacteria and detected viable L. monocytogenes sensitively and specifically. For viable L.monocytogenes detection, enriched L. monocytogenes was treated with PMA prior to asymmetric PCR amplification. The detection limits of the combined IMS with nucleic acid lateral flow (NALF) biosensor for viable L. monocytogenes detection were 3.5 × 10³ CFU/mL in phosphate buffer solution and 3.5 × 10⁴ CFU/g in lettuce samples. The whole assay process of recognizing viable L. monocytogenes was completed within 6 h. The proposed biotin-exposure-mediated IMS combined with a disposable NALF biosensor platform posed no health risk to the end user, and possessed potential applications in the rapid screening and identification of foodborne pathogens.

Combination of Microfluidic Loop-Mediated Isothermal Amplification with Gold Nanoparticles for Rapid Detection of Salmonella spp. in Food Samples

Foodborne diseases are an important cause of morbidity and mortality. According to the World Health Organization, there are 31 main global hazards, which caused in 2010 600 million foodborne illnesses and 420000 deaths. Among them, Salmonella spp. is one of the most important human pathogens, accounting for more than 90000 cases in Europe and even more in the United States per year. In the current study we report the development, and thorough evaluation in food samples, of a microfluidic system combining loop-mediated isothermal amplification with gold nanoparticles (AuNPs). This system is intended for low-cost, in situ, detection of different pathogens, as the proposed methodology can be extrapolated to different microorganisms. A very low limit of detection (10 cfu/25 g) was obtained. Furthermore, the evaluation of spiked food samples (chicken, turkey, egg products), completely matched the expected results, as denoted by the index kappa of concordance (value of 1.00). The results obtained for the relative sensitivity, specificity and accuracy were of 100% as well as the positive and negative predictive values.

Ultrasensitive Detection of Viable Enterobacter sakazakii by a Continual Cascade Nanozyme Biosensor

Recent outbreaks of life-threatening neonatal infections linked to Enterobacter sakazakii (ES) heightened the need to develop rapid and ultrasensitive detection strategies, especially those capable of determining the viable cells. This study introduced a continual cascade nanozyme biosensor for the detection of viable ES based on propidium monoazide (PMA), loop-mediated isothermal amplification (LAMP), and Nanozyme strip. The ompA gene of ES was determined using FITC-modified and BIO-modified primers in the LAMP process. LAMP combined with PMA treatment was applied for distinguishing the viable from the dead state of ES. Then, using Fe₃O₄ magnetic nanoparticles as a nanozyme probe, a magnetic nanoparticle (MNP)-based immunochromatographic strip (Nanozyme strip) was further employed for amplifying signal to allow visual detection and quantification by a strip reader. The LAMP products were sandwiched between the anti-FITC and the anti-BIO, and the accumulation of the Fe₃O₄ magnetic nanoparticles enabled the visual detection of ES. The detection limit of the nanozyme biosensor was improved by 10 CFU/mL compared with previously reported techniques, and the whole manipulation process was much faster (within 1 h) and simpler (without specialist facilities). Hence, the developed continual cascade nanozyme biosensor has provided a rapid, ultrasensitive, and simple tool for on-site detection of viable ES.

A Dual Filtration-Based Multiplex PCR Method for Simultaneous Detection of Viable Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus on Fresh-Cut Cantaloupe

Fresh-cut cantaloupe is particularly susceptible to contamination with pathogenic bacteria, such as Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus. Therefore, development of rapid, yet accurate detection techniques is necessary to ensure food safety. In this study, a multiplex PCR system and propidium monoazide (PMA) concentration were optimized to detect all viable pathogens in a single tube. A dual filtration system utilized a filtration membrane with different pore sizes to enrich pathogens found on fresh-cut cantaloupe. The results revealed that an optimized multiplex PCR system has the ability to effectively detect three pathogens in the same tube. The viable pathogens were simultaneously detected for PMA concentrations above 10 μg/ml. The combination of a nylon membrane (15 μm) and a micro pore filtration membrane (0.22 μm) formed the dual filtration system used to enrich pathogens. The achieved sensitivity of PMA-mPCR based on this dual filtration system was 2.6 × 103 cfu/g for L. monocytogenes, 4.3 × 10 cfu/g for E. coli O157:H7, and 3.1 × 102 cfu/g for S. aureus. Fresh-cut cantaloupe was inoculated with the three target pathogens using concentrations of 103, 102, 10, and 1 cfu/g. After 6-h of enrichment culture, assay sensitivity increased to 1 cfu/g for each of these pathogens. Thus, this technique represents an efficient and rapid detection tool for implementation on fresh-cut cantaloupe.

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

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.

Loop-mediated isothermal amplification (LAMP): methods for plant species identification in food

Loop-mediated isothermal amplification (LAMP) is a DNA-based analytical method that can be used as an isothermal alternative to polymerase chain reaction (PCR). In comparison to PCR, the advantage of LAMP is the possibility to perform the isothermal reaction without any sophisticated technical equipment; only a water bath is needed, and naked eye detection is sufficient. Up to now, an application of LAMP methods for the detection of even closely related plant species in food or feed matrices has not been described, whereas a large number of PCR methods for that topic are cited in the literature. The aim of the study was the evaluation of LAMP-based methods for plant species identification with respect to method parameters such as R(2), LOD, and LOQ. An existing (real-time) PCR method (for the detection of spices) was used for comparison. It could be shown that the developed LAMP methods have potential as alternative strategies to PCR in DNA-based analysis.