This study addresses the development and validation of an analytical method for speciation analysis of mercury (inorganic/Hg2+ and methylmercury/CH3Hg+) in fishery products. The Hg species are separated by reversed-phase (RP) high-performance liquid chromatography (HPLC) coupled to inductively coupled plasma mass spectrometry (ICP-MS). The effective separation of Hg2+ and CH3Hg+ was achieved in <8 min using a peptide mapping RP column and a mobile phase containing 2-mercaptoethanol at 0.25% (v/v) and methanol at 1% (v/v). The optimization was carried out using an experimental design through response surface methodology (RSM) with central composite design (CCD), addressing both the HPLC separation and the sample extraction. The method validation was carried out based on the accuracy profile approach. For this purpose, six series of measurements were carried out in duplicate over a time span of 2 months. The limits of quantification (LOQ) were 2.5 µg/kg (wet weight, ww) for CH3Hg+ and 1.2 µg/kg (ww) for Hg2+. The intermediate reproducibility in terms of coefficient of variation (CVR) was <6%. The bias (%) obtained for the analysis of four certified reference materials (CRMs), namely TORT-3 (lobster hepatopancreas), SRM 1566-b (oyster tissue), SQID-1 (cuttlefish) and NMIJ CRM 7402-a (cod fish tissue) was <7%. This demonstrates the method robustness and suitability for routine speciation analysis of CH3Hg+ and Hg2+ in fishery products. The method is intended to be applied for the analysis of the panel of fishery products and fish-based foods in the framework of the (ongoing) third French Total Diet Study.

Fishery products are one of the main human nutritional sources, and due to the consumption increase, the quality of the derived products may be modified, during catching, technological processing, and storage. Detection and identification of pathogenic and spoilage microorganisms in fishery products is needed because the first may be involved in human diseases, while the second is responsible of significant economic losses. In this sense, liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method and computational analysis of MS data are useful tools for characterizing and identifying different microorganisms and to develop promising strategies for food science investigations. Moreover, in the past decade, metaproteomic methodologies have progressed for the study of microorganisms isolated from their natural samples and independently of the culture restrictions. Metaproteomics enables assessment of proteins and pathways from individual members of the consortium. Metaproteomics can provide a detailed understanding of which organisms occupy specific metabolic niches, how they interact, and how they utilize nutrients, and these insights can be obtained directly from environmental samples.According to that, the sample preparation of the fishery product, the LC-ESI-MS/MS dedicated method, and the MS data analysis were described in the present chapter to obtain the metaproteomic analysis of the respective microbiomes or microbial communities.

Eastern China is a major producer of fishery products (including inland aquaculture, coastal mariculture, and coastal fishing products). The quality of the products is affected by hydrophobic organic contaminants (HOCs) in the sediments. Based on in-vitro luminescent bacterial assay, the baseline toxicity (BEQBio) of 56 common HOCs were assessed in the present study. Specifically, the BEQBio of sediments declined from land (31-400 mg/kg) to sea (9.1-270 mg/kg). However, the toxicity contribution explained by the HOCs increased gradually from land (0.70 %) to sea (10 %) using Iceberg Modeling. In the inland pond, current use HOCs (pyrethroid pesticide (PEs), organic tin (OTCs), and antibiotic) exhibited considerable concentrations, although their toxicity contribution was very small (0.076 %), thus more regulations on the use of HOCs should be proposed and further screening is needed to confirm the major toxicants. In coastal mariculture area, the toxicity contribution of current use HOCs further declined (0.010 %), whereas environmental background HOCs, such as polycyclic aromatic hydrocarbons (PAHs), became increasingly significant, with the contribution ratio increasing from 0.37 % to 2.4 %. To minimize the negative impacts of PAHs, optimization of energy structure in transportation and coastal industry is required. In the coastal fishing area, the phased-out persistent organic pollutants (POPs) remained a major concern, in terms of both concentration and toxicity contribution. The phased-out POPs explained 7.0 % of the toxic effects of the sediments from the coastal fishing area, due to historical residue, industrial emissions, and their high toxicities. For this reason, it is critical to improve the relevant emission regulations and standards, so as to eventually reduce the unintentional discharges of POPs.

The aim of this study was to assess the risk of pesticide contamination in aquaculture and its impact on fishery products. We conducted an assessment of 300 samples collected from nine regions in South Korea, including various types of seafood, such as freshwater fish, marine fish, crustaceans, and shellfish. Pesticide residues in seafood were analyzed using GC-MS/MS after sample preparation using a modified QuEChERS method, revealing the presence of eight pesticides (4,4\'-DDE, 4,4\'-DDT, boscalid, isoprothiolane, oxadiazon, pendimethalin, thifluzamide, and trifluralin) across seven fish species (carp, far eastern catfish, crucian carp, eel, Chinese muddy loach, mirror carp, and sea bass). Following the grouping of DDE with DDT, a risk assessment of fishery products was conducted. After the estimated daily intake (EDI) of fish was calculated and compared with the acceptable daily intake (ADI), the health risk index (HI, %ADI) of the detected pesticides was evaluated and found to be 1.07% or lower. The results suggest that the consumption of domestically farmed fish products in South Korea poses minimal health risks associated with pesticide residues.

A cloth-based analytical device combined with electrochemiluminescence detection (CAD-ECL) was described for rapid determination  of histamine (HA). The CAD device was produced by screen-printing a conductive carbon ink onto a patterned hydrophobic electrochemical microfluidic chamber to fabricate the three-carbon electrode system on a single hydrophilic cloth. The introduction of carbon nanodots linked to chitosan on the working carbon electrode surface enhanced the catalytic performance and overcame the resistance of the cotton fiber material. On this basis, the enhancement of the electrochemiluminescence (ECL) signal of the tris(2,2\'-bipyridyl) ruthenium(II) complex, caused by HA, was observed in a phosphate buffer solution at pH 7.6. The proposed CAD-ECL sensor was successfully applied to the quantification of HA in fish and fishery samples with good linearity between ECL intensity and the logarithm of HA concentration in the range 1.0 to 1000.0 µg L-1 with a low detection limit of 0.82 µg L-1.

This study aims to detect Clostridium botulinum and its control using natural leaf extracts of Citrus limon, Citrus sinensis, and Citrus unshiu in Egyptian fish products, e.g., canned tuna, canned sardine, canned mackerel, fesikh, moloha, and renga, as well the application of C. limon in tuna. Moreover, the antibacterial activity of the C. limon leaf extract was also estimated. In the water extract, ascorbic acid, total flavonoid content (TFC), and total phenolic content (TPC) were determined by volumetric, aluminum chloride, and Folin-Ciocalteu approaches, respectively. The antioxidant ability of the extract was analyzed in vitro via free radical scavenging (DPPH) and Ferric reducing assays. The results showed variability in the distribution of the total number of positive C. botulinum in fish samples from three different governorates under study, which were (24) Alexandria, (16) Beheira, and (17) Gharbia, out of the 120 tested samples in each governorate. Additionally, the findings revealed that all three Citrus extracts contain an appropriate number of secondary metabolites, with a sustainable presence of saponin and tannins in the C. limon extract. Furthermore, all Citrus extracts inhibited bacterial growth by increasing the inhibition zone, with C. limon being the best extract (25 mm) compared to C. sinensis and C. unshiu. The overall results showed the high antioxidant and anti-Clostridium powers (p < 0.05) of C. limon leaf extract, indicating its preservative activity in fishery products during storage. Finally, C. limon leaf extract can fight off C. botulinum and is considered a promising natural preservation candidate in ensuring safe and fresh fishery products.

In recent years, plastic waste has become a universally significant environmental problem. Ingestion of food and water contaminated with microplastics is the main route of human exposure. Fishery products are an important source of microplastics in the human diet. Once ingested, microplastics reach the gastrointestinal tract and can be absorbed causing oxidative stress, cytotoxicity, and translocation to other tissues. Furthermore, microplastics can release chemical substances (organic and inorganic) present in their matrix or previously absorbed from the environment and act as carriers of microorganisms. Additives present in microplastics such as polybrominated diphenyl ethers (PBDE), bisphenol A (BPA), nonylphenol (NP), octylphenol (OP), and potentially toxic elements can be harmful for humans. However, to date, the data we have are not sufficient to perform a reliable assessment of the risks to human health. Further studies on the toxicokinetics and toxicity of microplastics in humans are needed.

The performances of three non-destructive sensors, based on different principles, bioelectrical impedance analysis (BIA), near-infrared spectroscopy (NIR) and time domain reflectometry (TDR), were studied to discriminate between unfrozen and frozen-thawed fish. Bigeye tuna (Thunnus obesus) was selected as a model to evaluate these technologies. The addition of water and additives is usual in the fish industry, thus, in order to have a wide range of possible commercial conditions, some samples were injected with different water solutions (based on different concentrations of salt, polyphosphates and a protein hydrolysate solution). Three different models, based on partial least squares discriminant analysis (PLS-DA), were developed for each technology. This is a linear classification method that combines the properties of partial least squares (PLS) regression with the classification power of a discriminant technique. The results obtained in the evaluation of the test set were satisfactory for all the sensors, giving NIR the best performance (accuracy = 0.91, error rate = 0.10). Nevertheless, the classification accomplished with BIA and TDR data resulted also satisfactory and almost equally as good, with accuracies of 0.88 and 0.86 and error rates of 0.14 and 0.15, respectively. This work opens new possibilities to discriminate between unfrozen and frozen-thawed fish samples with different non-destructive alternatives, regardless of whether or not they have added water.

Seafood substitutions is a global problem and come under the spotlight in recent years. In Taiwan, Greenland halibut is usually substituted for the cod because of its lower price. Nowadays, DNA technology is widely used for fish species identifications; however, it still has concern about the DNA of processed fishery products might be destroyed. This study was designed to develop a proteomic-based method for fish and fishery product authentication by using ultra performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) with Sequential window acquisition of all theoretical fragment ion spectra (SWATH). The protein biomarkers from the meat of Alaska pollock, Atlantic cod, and Greenland halibut were identified and validated for species authentication of cod and corresponding fishery products, which might prevent consumer substitutions and fish product mislabeling. Besides, the E. coli proteins can be measured from existing SWATH-MS data though retrospective analysis successfully, it might present the quality of fish meat.

The mi-iuy croaker Miichthys miiuy has immense commercial value in the Republic of Korea. The red drum Sciaenops ocellatus is widely produced by aquaculture, although its price is approximately 25% that of M. miiuy. S. ocellatus has black spots on its tail, enabling it to be distinguished from M. miiuy based on appearance. However, identifying S. ocellatus after simple processing steps, such as skin removal and dicing, is difficult. Certain traders misrepresent and sell S. ocellatus as M. miiuy or cultured M. miiuy for illegal economical gain. Therefore, an accurate and rapid identification method is required to distinguish between M. miiuy and S. ocellatus in the field. Here, a method for rapid field identification was developed based on species-specific primers using a portable ultra-fast PCR instrument. The ultra-fast real-time PCR method can complete the entire analytical procedure, including DNA isolation, amplification, and detection, within 30 min, thus maintaining the accuracy of identifying M. miiuy and S. ocellatus products on site. Forty-nine commercial products were tested, and all samples were successfully identified. Thus, the developed method is rapid, efficient tool for ensuring consumer protection.
UNASSIGNED: The online version contains supplementary material available at 10.1007/s10068-021-00954-4.