Consumers’ perception toward quality and safety of fishery products,Beijing, China

Consumers around the world increased consumption of fish and fish products in recent years due to recognition of their nutritional value. Frequent occurrences of food safety scares heightened public awareness causing significant reduction in the consumption of the affected products. Many countries, including China, implemented a traceability system to increase vertical coordination and guarantee safety in fish products. This paper aims to provide information on consumers’ awareness to quality and safety of fish products, purchasing behavior, and willingness to pay (WTP) for safe fish products in Beijing, China, based on a survey of consumers. The results show a shortage of safety knowledge among customers concerning fish products, including processing, storage, and the traceability system. The age of consumers, educational level, the perception safety and the average price, are the main determinants of Beijing consumer’s WTP for the traceable products. On average, consumers are willing to pay a 6% premium for safe, traceable fish products over the price of non-traced products of uncertain safety.     

Method validation in the determination of aflatoxins in noodle samples using the QuEChERS method (Quick,Easy, Cheap,Effective, Rugged and Safe) and high performance liquid chromatography coupled to a fluorescence detector (HPLC–FLD)

A new method for the determination and analysis of aflatoxins in noodles, based on the use of the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) procedure, enhanced with a high performance liquid chromatography–coupled to a fluorescence detector (HPLC–FLD) has been developed. The method excludes the use of dispersive solid-phase extraction (dSPE) extraction cleanup step to reduce time and cost of analysis. Separation of the four(4) aflatoxins with higher selectivity and sensitivity, and within reasonable limits of retention time, was performed by using an isocratic mobile phase of water/methanol/acetonitrile (65/25/10) at a column temperature of 30 °C. Optimization of sample preparation and analytical conditions gave recoveries in the range of 75%–107% at spike levels of 5.0–20.0 μg/kg, and relative standard deviations (RSDs) lower than 13% in all the cases. The repeatability and reproducibility results were in range of 2.0–12.3% and 3.4–16.5% respectively. Additionally, the limits of detection (LOD) (0.01–1.00 μg/kg) and the limits of quantification (LOQ) (0.05–1.80 μg/kg) of these aflatoxins are well within the legal limits set by the European Union (EU).     

Consumers’ familiarity with and attitudes towards food quality certifications for rice and vegetables in Vietnam

This study investigates consumers’ attitudes towards, and familiarity with, food quality certification in selected urban areas in the South of Vietnam. Cross-sectional data were collected by means of a consumer survey (n = 500). Consumers’ awareness of food quality-related terms was relatively low. Less than half the participants claimed to understand the meaning of good agricultural practices (GAP), organic food and sustainability. Consumers’ familiarity with food quality certification (Vietnamese Good Agricultural Practices (VietGAP), Global Good Agricultural Practices (GLOBALG.A.P.), organic, and Hazard Analysis and Critical Control Points (HACCP)) was also low. Familiarity with food quality certification was positively associated with general attitude and food choice motives, namely food safety concern, perceived importance of healthy eating, and perceived importance of environmental consequences relating to food purchase. Food safety concern and perceived importance of environmental consequences were positively associated with consumers’ attitudes towards safe vegetables, as well as high quality rice. Perceived importance of healthy eating was positively related to attitude towards high quality rice. Findings suggest that food safety aspects of safe vegetables and high quality rice should be emphasized during policy and marketing activities for food quality certification. Additionally, an increase in the perceived importance of environmental consequences relating to quality food purchase should be encouraged to enhance positive consumer attitudes towards quality food. Efforts to improve public awareness and knowledge of food quality certification and sustainable agricultural practices in developing countries such as Vietnam are highly recommended.     

Porous structure and reduced sensitivity of 2,2’,4,4’,6,6’-hexanitrostilbene (HNS) prepared by different solvation and desolvation methods

ABSTRACT

The sensitivity and performance of energetic materials strongly depend on their microstructure. Different solvation and desolvation methods were applied to prepare high explosive HNS with modified porous structure. Vacuum pyrolysis and a novel anti-solvent extraction method have been applied on the desolvation of the HNS?DIO (HNS = 2,2?,4,4?,6,6?-hexanitrostilbene; DIO = 1,4-dioxane) solvate to obtain porous HNS, while in the solvation process, the porous HNS was exposed to the solvent vapor generated by low vacuum or heating to form porous HNS?DIO solvates. After the desolvation of the porous HNS?DIO solvates, HNS with modified porous structure was achieved. This porous HNS and modified porous HNS reveal a reduced impact and friction sensitivity, compared to the raw HNS. The microstructures of HNS tuned by these different supramolecular assembly and disassembly methods were described and the feature of the methods was also discussed. These results highlight a new, simple, effective and controllable crystal engineering strategy for the design and optimization of the microstructure of energetic materials.     

Listeria monocytogenes in ready-to-eat,sliced, cooked ham and salami products,marketed in the city of São Paulo,Brazil: Occurrence,quantification, and serotyping

The preference for ready-to-eat sliced foods may pose an increased risk for food-borne diseases, and a major concern is the presence of Listeria monocytogenes. L. monocytogenes was assessed in two types of products: cooked ham and salami. One hundred and thirty samples of each product were acquired in retail shops in the city of São Paulo and submitted to laboratory analysis. The rate of positives was significantly higher in salami samples than in ham samples (6.2% and 0.8%, respectively). L. monocytogenes counts in salami samples varied between <10 and 1900 colony-forming units per gram (CFU/g). The serotypes found in both products were as follows, according to incidence: 4b (37.5%), 1/2b (25%), 3b (25%), and 1/2c (12.5%). Based on the results of the present study, the authors suggest that the risk of listeriosis resulting from the consumption of salami is higher than that associated with the consumption of cooked ham.     

DNA barcoding reveals chaotic labeling and misrepresentation of cod (鳕, Xue) products sold on the Chinese market

The increasing rate of seafood frauds, especially in the case of highly priced species, highlights the need of verifying the identity of fish products. This paper describes the application of DNA barcoding to the identification of 52 products commercialized with the Chinese term 鳕 (Xue, Cod) in supermarkets (Nanjing and Shanghai) and in the online market. Considering the lack of harmonization around the definition of Cod, the mislabeling rate was assessed according to three increasingly stringent definitions: Cod meaning Gadiformes species; Cod meaning Gadus spp.; Cod not meaning any specific species, since a qualifier (“Atlantic”, “Pacific” or “Greenland”) should be added in order to refer to Gadus morhua, Gadus macrocephalus or Gadus ogac, respectively.Results highlighted a very high mislabeling rate, which exceeded 60% even with the less stringent definition. Interestingly, only 42.3% of the samples were Gadiformes, while the others were Perciformes, Pleuronectiformes or toxic Tetraodontiformes species. Economic, ecological and health issues arising from the misuse of the term Cod are discussed in the light of the leading role of China in the seafood worldwide industry and of the increased national consumption of marine species.     

Simultaneous determination of ethyl carbamate,chloropropanols and acrylamide in fermented products,flavoring and related foods by gas chromatography–triple quadrupole mass spectrometry

A simultaneous determination method was established by gas chromatography–triple quadrupole mass spectrometry (GC–MS/MS) for ethyl carbamate, acrylamide and chloropropanols (1,3-dichloropropane-2-ol (1,3-DCP), 2,3-dichloropropane-1-ol (2,3-DCP), 3-monochloropropane-1,2-diol (3-MCPD) and 2-monochloropropane-1,3-diol (2-MCPD)) in fermented products, flavoring and related foods. Ethyl carbamate-d₅, 1,3-DCP-d₅, 3-MCPD-d₅ and acrylamide-d₃ were used as isotope internal standards for ethyl carbamate, DCPs, MCPDs and acrylamide, respectively. The sample was extracted and cleaned in one single step by a combined clean-up column packed with Extrelut™ NT and primary secondary amine (PSA). The concentrated extract was directly injected without derivatization, separated by an Innowax (cross-bonded polyethylene glycol) capillary column and measured by GC–MS/MS. The calculated limits of detection (LODs) in the sample matrix were 1.8, 1.0, 2.1, 5.3, 5.1 and 5.0 μg kg⁻¹ for ethyl carbamate, 1,3-DCP, 2,3-DCP, acrylamide, 3-MCPD and 2-MCPD, respectively. The average recoveries in different matrices at three spiked concentration levels (20, 100 and 400 μg kg⁻¹) were 88.6–112, 92.6–103, 92.1–106, 86.2–107, 90.4–109 and 91.0–105% with relative standard deviations (RSDs) (Average RSDs in bracket) of 4.4–10.2 (6.4%), 3.7–7.3 (5.4%), 3.9–7.7 (5.2%), 4.4–9.3 (6.4%), 4.1–10.7 (6.3%) and 3.7–7.9% (5.6%), respectively. Two to six contaminants were simultaneously found in some of the soy sauce samples. Ethyl carbamate, acrylamide, 3-MCPD and 2-MCPD were found in the instant noodle flavoring. Trace levels (<12 μg kg⁻¹) of ethyl carbamate, acrylamide or 3-MCPD were detected in tomato sauce and salad dressing. Both ethyl carbamate and acrylamide were found in some of the curry products and Chinese yellow rice wine. Only ethyl carbamate was found in beer and grape wine.     

The application of PCR–RFLP and FINS for species identification used in sea cucumbers (Aspidochirotida: Stichopodidae) products from the market

Sea cucumbers are traditional, delicious and luxurious seafood in Asia. They are usually provided to the consumers in the marketing formats of dried or frozen products. At the commercial level, they are much different not only in flavor, but also in price. The processing treatment makes them difficult for species identification based on morphological characterization. In this study, two molecular methods are developed to identify six species belonging to family Stichopodidae in commercial products. The first one is PCR–RFLP (polymerase chain reaction–restriction fragment length polymorphism), which uses PCR amplification of a common 570 bp fragment of the 16S rRNA gene and follows codigestion with two restriction enzymes (XmnI and MwoI). Another one is FINS (forensically informative nucleotide sequencing) of the 16S rRNA gene, and the key of the method is the phylogenetic analysis of 16S rRNA gene sequences. The PCR–RFLP methodology can be used to authenticate the species tested in the present study and allow us to detect a fraudulent labeling of frozen Apostichopus japonicus product. And the FINS methodology confirms that the species substituted for A. japonicus belongs to the genera Isostichopus. Therefore, two molecular tools really provide convenient, useful and academic techniques to authenticate the species of commercial sea cucumber products.     

2,2-二甲基-3-(4’,6’-二氯-1’,3’,5’-均三嗪)噁唑烷的制备

以三聚氯氰、乙醇胺和丙酮为原料,合成了一种新型噁唑烷,通过红外光谱(IR)、氢核磁共振波谱法(1H-NMR)和电喷雾电离质谱(ESI-MS)对其结构进行了表征。采用正交试验,确定了最佳合成条件:反应体系pH为9,n(丙酮)∶n(中间体)=2∶1,反应时间为3 h。     

Official Commissioning of BP’s PTA Unit (Phase Ⅱ) in Zhuhai

The phase-II PTA unit of the BP Chemical Company, Ltd. inZhuhai was officially put on stream on November 20, 2008.It is learned that BP Chemical Company, Ltd. in Zhuhai isthe first Sino-foreign JV enterprise (with BP and the Fuhua     

Comparison of the RAPID-B® flow cytometer and the BAX® system for the detection of non-O157 shiga toxin-producing Escherichia coli (STEC) in beef products

The beef industry continues to be interested in reliable rapid detection technologies for shiga toxin-producing Escherichia coli (STEC). Current rapid technologies require several hours of pre-enrichment and additional time on the rapid technology instrument. A flow cytometer-based system (RAPID-B^®) has been shown to improve the turn-around for results with a more rapid pre-enrichment requiring only 6.5 h pre-enrichment for a 25 g and 8.5 h for a 375 g sample, followed by an additional 30 min time to achieve final results using the screening technology. The purpose of this study was to validate the RAPID-B^® technology for non-O157 STEC detection as compared to the USDA-FSIS reference method which utilizes the BAX^® system. A total of 180 STEC isolates from various sources and 20 non-STEC strains were used to evaluate specificity and sensitivity using the RAPID-B^® flow cytometer. Also, three different weights (25, 325 and 375 g) of beef trim and ground beef samples were spiked with each STEC to verify detection sensitivity of BAX^® system and RAPID-B^® flow cytometer. For both methods, samples were confirmed by culturing using the USDA-FSIS reference method regardless of the screening result. The RAPID-B^® flow cytometer showed that 180 isolates were all positive and the 20 non-STEC strains were all negative. For spiked beef samples, overall detection sensitivity was the same for both the BAX^® system and RAPID-B^® flow cytometer. When detection sensitivity was based on sample weight, there was no differences in 25 and 375 g samples between RAPID-B^® flow cytometer and USDA-FSIS reference method. The RAPID-B^® system yielded the same sensitivity as the reference method with a decrease of over 10 h of pre-enrichment time and 3 h of rapid screening detection time. In conclusion, the RAPID-B^® flow cytometer based on whole cell detection generated similar results as BAX^® system therefore the RAPID-B^® flow cytometer system could be a valuable rapid method for the detection of non-O157 STEC in beef products.     

Synthesis and thermal properties of 1, 3-dinitro-3-(1′, 3′-dinitroazetidin-3′-yl) azetidine (tndaz) and its admixtures with 1, 3, 3-trinitroazetidine (TNAZ)

Abstract

The synthesis of TNDAZ in four steps by starting with N-t-butyl-3-hydroxymethyl-3-nitroazetidine is described. The structures of TNDAZ and of a precursor, N-t-butyl-3-nitro-3-(N'-t-butyl-3′-nitroazetidin-3′-yl) azetidine, have been established unequivocally via application of single crystal x-ray crystallographic techniques. Thermal properties of TNDAZ, TNAZ and admixtures thereof are presented. A binary phase diagram has been predicted computationally and confirmed experimentally by using differential scanning calorimetry and hot stage microscopy. The thermal data support the existence of more than one polymorph for TNDAZ and for TNAZ.     

Polycyclic aromatic hydrocarbons (PAHs) in yerba maté (Ilex paraguariensis St. Hil) traditional infusions (mate and tereré)

This study describes the occurrence of polycyclic aromatic hydrocarbons (PAHs) in traditional yerba maté hot and cold infusions (mate and tereré), by monitoring the content of benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[ah]anthracene, benzo[ghi]perylene and indeno[1,2,3-cd]pyrene (PAH8), that have been chosen as indicators for the occurrence and toxicity of PAHs in food by the European Food Safety Agency. PAH8 content in mate and tereré was determined by high performance liquid chromatography using fluorescence detection (HPLC-FLD).PAH8 contents in hot and cold maté infusions ranged from 371.2 to 2438.8 ng/L and from 19.2 to 937.3 ng/L, respectively. Benzo[a]pyrene contents varied between 37.0 and 373.9 ng/L in hot yerba maté infusions and between 7.0 and 92.1 ng/L in cold yerba maté infusions. None of the samples analyzed exceeded the World Health Organization criteria for drinking water, since the maximum level allowed for benzo[a]pyrene is 700 ng/L.     

Chemical taste taint accumulation in RAS farmed fish – A Fr 13 risk assessment demonstrated with geosmin (GSM) and 2-methylisoborneol (MIB) in barramundi (Lates calcarifer)

Recirculating Aquaculture System (RAS) farming of fish is becoming widespread. However, taste taint accumulation in the fish flesh as geosmin (GSM) and/or 2-methylisoborneol (MIB) is a major concern for farmers and consumers. Here we apply the emerging Fr 13 risk methodology (Food Control 50 (2015) 770–777; Food Control 29 (2013) 248–254) to demonstrate quantitatively the impact of naturally occurring fluctuations in these chemicals in RAS water on their accumulation in fish flesh. The approach is based on the time dependent accumulation model of Hathurusingha and Davey (Ecological Modelling 291 (2014) 242–249) in which taint chemicals enter the flesh via the gills and are diluted through metabolism and growth, together with a risk factor (p) such that for all p > 0 the chemical taint is above a desired threshold concentration (which includes a practical tolerance) respectively, 0.814 and 0.77, μg kg⁻¹ for GSM and MIB. Monte Carlo (with Latin Hypercube) sampling of chemical in the growth water (C_W), water temperature (T) and growth time (t) was used to simulate practical RAS farmed barramundi (Lates calcarifer), a premium fish, for up to 260 days growth. Results show some 10.10% of all harvests over the long term will result in fish with taste taint as GSM above the threshold concentration due to natural fluctuations in the RAS environment. For MIB this failure rate is 10.56%. The vulnerability to taste taint failure is shown to be impacted highly significantly by the time to harvest, and to a lesser extent by concentration and fluctuation of the taint chemicals in the RAS water. An advantage is growth time can be readily controlled by farmers; this should not exceed 240 day. The methodology appears generalizable and therefore applicable to a range of RAS farmed foods. Findings will be of immediate benefit to RAS farmers and to risk researchers in foods processing.     

Screening and confirmatory methods for the determination of melamine in cow’s milk and milk-based powdered infant formula: Validation and proficiency-tests of ELISA,HPLC-UV,GC-MS and LC-MS/MS

In recent years, two adulteration incidents concerning the addition of melamine, a small polar compound which is very rich in nitrogen, to pet food and infant formula products have occurred in China. These issues prompted private as well as governmental laboratories to develop methods for the analysis of melamine and related compounds in a wide variety of food products and ingredients. The development of methods was focussed on both, screening and quantification purposes, ranging from highly sophisticated chromatographic-mass spectrometric techniques to immuno-selective assays. The present work describes two screening and two confirmatory methods dedicated to the determination of melamine in cow’s milk and milk-based powdered infant formula. Screening methods are enzyme-linked immunosorbent assay (ELISA) and liquid chromatography coupled to ultraviolet detection, while confirmatory methods are based on gas and liquid chromatography coupled mass spectrometry techniques. Performance and validation data of the four methods, and results obtained in the frame of internal and European proficiency-tests are shown.     

Characteristics of Oil and Gas Accumulation in Yong’an-Meitai Area of the Fushan Depression, Beibuwan Basin, South China Sea

The Yong’an-Meitai area is the focus of the present exploration in the Fushan Depression, Beibuwan Basin, South China Sea. All oils from this area are geochemically characterized by higher Pr/Ph ratio, higher proportion of heavy molecular weight hydrocarbons, and higher proportion of C29 regular steranes, which indicate that the organic matter of source rocks might have been deposited in an oxidizing palaeoenvironment and be dominated by higher plant organic matter input. The oil from E3w2 (the second member of Weizhou Fm. of the Oligocene) has a much higher density, relatively higher Pr/nC17 and Ph/nC18 ratios, and a “UCM—unresolved complex mixture” on gas chromatograms, which indicate that it has been slightly biodegraded. CPI and other terpane and sterane isomer ratios suggest they are all mature oils. The timing of oil charging in E3w2 and E2l1 (the first member of the Liushagang Fm. of the Eocene) determined by the homogenization temperatures of fluid inclusions and thermal evolution history are from 9-3 Ma and 8-3 Ma, respectively. Thus, the interpretation of E3w2 as a secondary reservoir is unlikely. The timing of oil charging is later than that of hydrocarbon generating and expulsion of Liushagang Fm. source rocks and trap formation, which is favorable for oil accumulation in this area. All molecular parameters that are used for tracing oil filling direction decrease with shallower burial depth, which suggests vertical oil migration. The widely occurring faults that penetrate through the source rocks of the Liushagang Fm. may serve as a fine oil charging conduit.