On-site paper-based Loop-Mediated Isothermal Amplification coupled Lateral Flow Assay for pig tissue identification targeting mitochondrial CO I gene

The Utilization of the SaLux19-Based Loop-Mediated Isothermal Amplification (LAMP) Assay for the Rapid and Sensitive Identification of Minute Amounts of a Biological Specimen

Our research has developed a highly sensitive and simple assay to detect small amounts of animal and human biological material in less than 40 min. The handheld SaLux19 device developed at the Max Planck Institute of Experimental Medicine in Göttingen, Germany, was used to validate our concept. The proposed system uses isothermal amplification of DNA in a rapid assay format. Our results show that the assay can detect Sus scrofa nucleic acids with very high sensitivity and specificity. This detection system has potential for forensic scenarios.

Recent advancements with loop-mediated isothermal amplification (LAMP) in assessment of the species authenticity with meat and seafood products

Species adulteration or mislabeling with meat and seafood products could negatively affect the fair trade, wildlife conservation, food safety, religion aspect, and even the public health. While PCR-based methods remain the gold standard for assessment of the species authenticity, there is an urgent need for alternative testing platforms that are rapid, accurate, simple, and portable. Owing to its ease of use, low cost, and rapidity, LAMP is becoming increasingly used method in food analysis for detecting species adulteration or mislabeling. In this review, we outline how the features of LAMP have been leveraged for species authentication test with meat and seafood products. Meanwhile, as the trend of LAMP detection is simple, rapid and instrument-free, it is of great necessity to carry out end-point visual detection, and the principles of various end-point colorimetry methods are also reviewed. Moreover, with the aim to enhance the LAMP reaction, different strategies are summarized to either suppress the nonspecific amplification, or to avoid the results of nonspecific amplification. Finally, microfluidic chip is a promising point-of-care method, which has been the subject of a great deal of research directed toward the development of microfluidic platforms-based LAMP systems for the species authenticity with meat and seafood products.

Rapid analysis technologies with chemometrics for food authenticity field: A review

In recent years, the problem of food adulteration has become increasingly rampant, seriously hindering the development of food production, consumption, and management. The common analytical methods used to determine food authenticity present challenges, such as complicated analysis processes and time-consuming procedures, necessitating the development of rapid, efficient analysis technology for food authentication. Spectroscopic techniques, ambient ionization mass spectrometry (AIMS), electronic sensors, and DNA-based technology have gradually been applied for food authentication due to advantages such as rapid analysis and simple operation. This paper summarizes the current research on rapid food authenticity analysis technology from three perspectives, including breeds or species determination, quality fraud detection, and geographical origin identification, and introduces chemometrics method adapted to rapid analysis techniques. It aims to promote the development of rapid analysis technology in the food authenticity field.

Recent Uses of Paper Microfluidics in Isothermal Nucleic Acid Amplification Tests

Isothermal nucleic acid amplification tests have recently gained popularity over polymerase chain reaction (PCR), as they only require a constant temperature and significantly simplify nucleic acid amplification. Recently, numerous attempts have been made to incorporate paper microfluidics into these isothermal amplification tests. Paper microfluidics (including lateral flow strips) have been used to extract nucleic acids, amplify the target gene, and detect amplified products, all toward automating the process. We investigated the literature from 2020 to the present, i.e., since the onset of the COVID-19 pandemic, during which a significant surge in isothermal amplification tests has been observed. Paper microfluidic detection has been used extensively for recombinase polymerase amplification (RPA) and its related methods, along with loop-mediated isothermal amplification (LAMP) and rolling circle amplification (RCA). Detection was conducted primarily with colorimetric and fluorometric methods, although a few publications demonstrated flow distance- and surface-enhanced Raman spectroscopic (SERS)-based detection. A good number of publications could be found that demonstrated both amplification and detection on paper microfluidic platforms. A small number of publications could be found that showed extraction or all three procedures (i.e., fully integrated systems) on paper microfluidic platforms, necessitating the need for future work.

A Machine Learning Method for the Quantitative Detection of Adulterated Meat Using a MOS-Based E-Nose

Meat adulteration is a global problem which undermines market fairness and harms people with allergies or certain religious beliefs. In this study, a novel framework in which a one-dimensional convolutional neural network (1DCNN) serves as a backbone and a random forest regressor (RFR) serves as a regressor, named 1DCNN-RFR, is proposed for the quantitative detection of beef adulterated with pork using electronic nose (E-nose) data. The 1DCNN backbone extracted a sufficient number of features from a multichannel input matrix converted from the raw E-nose data. The RFR improved the regression performance due to its strong prediction ability. The effectiveness of the 1DCNN-RFR framework was verified by comparing it with four other models (support vector regression model (SVR), RFR, backpropagation neural network (BPNN), and 1DCNN). The proposed 1DCNN-RFR framework performed best in the quantitative detection of beef adulterated with pork. This study indicated that the proposed 1DCNN-RFR framework could be used as an effective tool for the quantitative detection of meat adulteration.

Inhibition of Non-specific Amplification in Loop-Mediated Isothermal Amplification via Tetramethylammonium Chloride

Loop-mediated isothermal amplification (LAMP) may be used in molecular and point-of-care diagnostics for pathogen detection. The amplification occurs under isothermal conditions using up to six primers. However, non-specific amplification is frequently observed in LAMP. Non-specific amplification has the potential to be triggered by forward and reverse internal primers. And the relatively low reaction temperature (55-65 °C) induces the secondary structure via primer-primer interactions. Primer redesign and probe design have been recommended to solve this problem. LAMP primers have strict conditions, such as Tm, GC contents, primer dimer, and distance between primers compared to conventional PCR primers. Probe design requires specialized knowledge to have high specificity for a target. In polymerase chain reaction (PCR), some chemicals or proteins are used for improving specificity and efficiency. Therefore, we hypothesized that additives can suppress the non-specific amplification. In this study, tetramethylammonium chloride (TMAC), formamide, dimethyl sulfoxide, Tween 20, and bovine serum albumin have been used as LAMP additives. In our study, TMAC was presented as a promising additive for suppressing non-specific amplification in LAMP.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13206-022-00070-3.

Rapid Full-Cycle Technique to Control Adulteration of Meat Products: Integration of Accelerated Sample Preparation, Recombinase Polymerase Amplification, and Test-Strip Detection

Verifying the authenticity of food products is essential due to the recent increase in counterfeit meat-containing food products. The existing methods of detection have a number of disadvantages. Therefore, simple, cheap, and sensitive methods for detecting various types of meat are required. In this study, we propose a rapid full-cycle technique to control the chicken or pig adulteration of meat products, including 3 min of crude DNA extraction, 20 min of recombinase polymerase amplification (RPA) at 39 °C, and 10 min of lateral flow assay (LFA) detection. The cytochrome B gene was used in the developed RPA-based test for chicken and pig identification. The selected primers provided specific RPA without DNA nuclease and an additional oligonucleotide probe. As a result, RPA-LFA, based on designed fluorescein- and biotin-labeled primers, detected up to 0.2 pg total DNA per μL, which provided up to 0.001% w/w identification of the target meat component in the composite meat. The RPA-LFA of the chicken and pig meat identification was successfully applied to processed meat products and to meat after heating. The results were confirmed by real-time PCR. Ultimately, the developed analysis is specific and enables the detection of pork and chicken impurities with high accuracy in raw and processed meat mixtures. The proposed rapid full-cycle technique could be adopted for the authentication of other meat products.