Development and validation of a triplex real-time PCR assay for the simultaneous detection of three mustard species and three celery varieties in food

Development of triplex PCR for simultaneous detection of soybean and wheat

There is a constant demand for an effective detection method of major allergens, such as soybean (Glycine max) and wheat (Triticum aestivum). In this study, a triplex polymerase chain reaction (PCR) method was developed for rapid detection of soybean and wheat in processed food products. This triplex PCR contains soybean- and wheat-specific primer pairs and universal primer pair for plant species. Each primer pair was applied to 22 different plant species and showed high specificity with no amplification in non-target species. The sensitivity of triplex PCR for soybean and wheat was 10 pg. The detection limit for soybean and wheat in pea mixture was 0.1%. The developed triplex PCR showed high sensitivity and specificity and was applied to 21 different commercial products. The results were in accordance with the label. Thus, this method is expected to be useful in preventing allergy-related issues via accurate labeling of major allergens in food.

Tetraplex real-time PCR assay for the simultaneous identification and quantification of roe deer, red deer, fallow deer and sika deer for deer meat authentication

Analytical methods are needed for the identification and quantification of meat species to detect food adulteration. Since game meat is more expensive than meat from domesticated animal species, it is a potential target for adulteration. We present a tetraplex real-time PCR assay that allows the simultaneous determination of the content of roe deer, red deer, fallow deer and sika deer. The tetraplex assay showed only moderate cross-reactivity with closely related species. After optimization the tetraplex assay had a limit of detection of 0.1% (w/w) and a limit of quantification of 0.5% (w/w) for each of the four deer species. The tetraplex assay was found to be robust, slight modifications of the experimental setup did not lower its performance. Recoveries obtained by analyzing DNA mixtures and DNA isolates from model game sausages were similar to those obtained with the singleplex assays.

Identification and Quantification of Celery Allergens Using Fiber Optic Surface Plasmon Resonance PCR

Abstract: Accurate identification and quantification of allergens is key in healthcare, biotechnology and food quality and safety. Celery (Apium graveolens) is one of the most important elicitors of food allergic reactions in Europe. Currently, the golden standards to identify, quantify and discriminate celery in a biological sample are immunoassays and two-step molecular detection assays in which quantitative PCR (qPCR) is followed by a high-resolution melting analysis (HRM). In order to provide a DNA-based, rapid and simple detection method suitable for one-step quantification, a fiber optic PCR melting assay (FO-PCR-MA) was developed to determine different concentrations of celery DNA (1 pM-0.1 fM). The presented method is based on the hybridization and melting of DNA-coated gold nanoparticles to the FO sensor surface in the presence of the target gene (mannitol dehydrogenase, Mtd). The concept was not only able to reveal the presence of celery DNA, but also allowed for the cycle-to-cycle quantification of the target sequence through melting analysis. Furthermore, the developed bioassay was benchmarked against qPCR followed by HRM, showing excellent agreement (R² = 0.96). In conclusion, this innovative and sensitive diagnostic test could further improve food quality control and thus have a large impact on allergen induced healthcare problems.

Food Allergy

Food allergy is receiving increased attention in recent years. Because there is currently no known cure for food allergy, avoiding the offending food is the best defense for sensitive individuals. Type I food allergy is mediated by food proteins, and thus, theoretically, any food protein is a potential allergen. Variability of an individual's immune system further complicates attempts to understand allergen-antibody interaction. In this article, we briefly review food allergy occurrence, prevalence, mechanisms, and detection. Efforts aimed at reducing/eliminating allergens through food processing are discussed. Future research needs are addressed.

Identification of four squid species by quantitative real-time polymerase chain reaction

Squids are distributed worldwide, including many species of commercial importance, and they are often made into varieties of flavor foods. The rapid identification methods for squid species especially their processed products, however, have not been well developed. In this study, quantitative real-time PCR (qPCR) systems based on specific primers and TaqMan probes have been established for rapid and accurate identification of four common squid species (Ommastrephes bartramii, Dosidicus gigas, Illex argentinus, Todarodes pacificus) in Chinese domestic market. After analyzing mitochondrial genes reported in GenBank, the mitochondrial cytochrome b (Cytb) gene was selected for O. bartramii detection, cytochrome c oxidase subunit I (COI) gene for D. gigas and T. Pacificus detection, ATPase subunit 6 (ATPase 6) gene for I. Argentinus detection, and 12S ribosomal RNA (12S rDNA) gene for designing Ommastrephidae-specific primers and probe. As a result, all the TaqMan systems are of good performance, and efficiency of each reaction was calculated by making standard curves. This method could detect target species either in single or mixed squid specimen, and it was applied to identify 12 squid processed products successfully. Thus, it would play an important role in fulfilling labeling regulations and squid fishery control.