Twenty-three years of PCR-based seafood authentication assay development: What have we learned?

Seafood is a prime target for fraudulent activities due to the complexity of its supply chain, high demand, and difficult discrimination among species once morphological characteristics are removed. Instances of seafood fraud are expected to increase due to growing demand. This manuscript reviews the application of DNA-based methods for commercial fish authentication and identification from 2000 to 2023. It explores (1) the most common types of commercial fish used in assay development, (2) the type of method used, (3) the gene region most often targeted, (4) provides a case study of currently published assays or primer-probe pairs used for DNA amplification, for specificity, and (5) makes recommendations for ensuring standardized assay-based reporting for future studies. A total of 313 original assays for the detection and authentication of commercial fish species from 191 primary articles published over the last 23 years were examined. The most explored DNA-based method was real-time polymerase chain reaction (qPCR), followed by DNA sequencing. The most targeted gene regions were cytb (cytochrome b) and COI (cytochrome c oxidase 1). Tuna was the most targeted commercial fish species. A case study of published tuna assays (n = 19) targeting the cytb region found that most assays were not species-specific through in silico testing. This was conducted by examining the primer mismatch for each assay using multiple sequence alignment. Therefore, there is need for more standardized DNA-based assay reporting in the literature to ensure specificity, reproducibility, and reliability of results. Factors, such as cost, sensitivity, quality of the DNA, and species, should be considered when designing assays.

Detection of SAR-CoV-2 on surfaces in food retailers in Ontario.

The COVID-19 pandemic has generated increased interest in potential transmission routes. In food retail settings, transmission from infected customers and workers and customers through surfaces has been deemed plausible. However, limited information exists on the presence and survival of SARS-CoV-2 on surfaces, particularly outside laboratory settings. Therefore, the purpose of this project was to assess the presence of the virus at commonly found surfaces at food retail stores and the potential role that these spaces play in virus transmission. Samples (n=957) were collected twice a week for a month in food-retail stores within Ontario, Canada. High-touch surfaces were identified and surveyed in 4 zones within the store (payment stations, deli counters, refrigerated food section and carts and baskets). The samples were analyzed using a molecular method, i.e., reverse transcriptase quantitative Polymerase Chain Reaction (RT-qPCR). Regardless of the store's location, the sampling day or time, the location of the surface within the store or the surface material, all samples tested negative for SARS-CoV-2. These results suggest that the risk of exposure from contaminated high-touch surfaces within a food retailer store is low if preventive measures and recommended sanitizing routines are maintained.

Validation of FASTFISH-ID: A new commercial platform for rapid fish species authentication via universal closed-tube barcoding.

Seafood represents up to 20% of animal protein consumption in global food consumption and is a critical dietary and income resource for the world's population. Currently, over 30% of marine fish stocks are harvested at unsustainable levels, and the industry faces challenges related to Illegal, Unregulated and Unreported (IUU) fishing. Accurate species identification is one critical component of successful stock management and helps combat fraud. Existing DNA-based technologies permit identification of seafood even when morphological features are removed, but are either too time-consuming, too expensive, or too specific for widespread use throughout the seafood supply chain. FASTFISH-ID is an innovative commercial platform for fish species authentication, employing closed-tube barcoding in a portable device. This method begins with asymmetric PCR amplification of the full length DNA barcode sequence and subsequently interrogates the resulting single-stranded DNA with a universal set of Positive/Negative probes labeled in two fluorescent colors. Each closed-tube reaction generates two species-specific fluorescent signatures that are then compared to a cloud-based library of previously validated fluorescent signatures. This novel approach results in rapid, automated species authentication without the need for complex, time consuming, identification by DNA sequencing, or repeated analysis with a panel of species-specific tests. Performance of the FASTFISH-ID platform was assessed in a blinded study carried out in three laboratories located in the UK and North America. The method exhibited a 98% success rate among the participating laboratories when compared to species identification via conventional DNA barcoding by sequencing. Thus, FASTFISH-ID is a promising new platform for combating seafood fraud across the global seafood supply chain.

Glycemic index of pulses and pulse-based products: a review.

Pulses are a major source for plant-based proteins, with over 173 countries producing and exporting over 50 million tons annually. Pulses provide many of the essential nutrients and vitamins for a balanced and healthy diet, hence are health beneficial. Pulses have been known to lower glycemic index (GI), as they elicit lower post prandial glycemic responses, and can prevent insulin resistance, Type 2 diabetes and associated complications. This study reviews the GI values (determined by in vivo methodology) reported in 48 articles during the year 1992-2018 for various pulse type preparations consumed by humans. The GI ranges (glucose and bread as a reference respectively) for each pulse type were: broad bean (40 ± 5 to 94 ± 4, 75 to 93), chickpea (5 ± 1 to 45 ± 1, 14 ± 3 to 96 ± 21), common bean (9 ± 1 to 75 ± 8, 18 ± 2 to 99 ± 11), cowpea (6 ± 1 to 56 ± 0.2, 38 ± 19 to 66 ± 7), lentil (10 ± 3 to 66 ± 6, 37 to 87 ± 6), mung bean (11 ± 2 to 90 ± 9, 28 ± 1 to 44 ± 6), peas (9 ± 2 to 57 ± 2, 45 ± 8 to 93 ± 9), pigeon peas (7 ± 1 to 54 ± 1, 31 ± 4), and mixed pulses (35 ± 5 to 66 ± 23, 69 ± 42 to 98 ± 29). It was found that the method of preparation, processing and heat applications tended to affect the GI of pulses. In addition, removal of the hull, blending, grinding, milling and pureeing, reduced particle size, contributed to an increased surface area and exposure of starch granules to the amylolytic enzymes. This was subsequently associated with rapid digestion and absorption of pulse carbohydrates, resulting in a higher GI. High or increased heat applications to pulses were associated with extensive starch gelatinization, also leading to a higher GI. The type of reference food used (glucose or white bread) and the other nutrients present in the meal also affected the GI.