Sauce-flavor baijiu is a popular Chinese baijiu. To avoid adulteration and market cheating, this study aims to develop a new, reliable, and accurate traceability system for characterization of the geographical origins. Totally, 100 samples collected from seven regions in Guizhou Province of China are analyzed, involving 13 trace elements, 5 organic acids, and stable carbon isotope composition of acetic acid. Based on these data, a geographical classification model is established. The origin accuracy is found to reach as high as 83%, thus providing a useful technique for authentication of the sauce-flavor baijiu and contributing to the healthy development of the baijiu industry in China.
Simultaneously verifying the original region of green and roasted coffee beans is very important for protecting legal interests of the stakeholder according to the chemical analyzing method. 131 green coffee bean samples are collected from six different original regions and pretreated with three degrees (green, middle, and dark roasted); five stable isotope ratios (δ13C, δ14N, δ18O, δ2H, and δ32S) and twelve elemental contents (Al, Cr, Ni, Zn, Ba, Cu, Na, Mn, Fe, Ca, K, and Mg) of green, middle, and dark roasted coffee bean samples (131×3) were analyzed. Fractionation of stable isotopes and variation of elemental contents were evaluated, only isotope hydrogen (2H) significantly fractionated, and elemental concentrations increased with a certain rate during the roasting process. One-way analysis of variance (ANOVA) was used to compare the stable isotope ratios and elemental concentrations of all coffee bean samples from six different original regions. Random forest (RF) was employed to build a discriminating model for simultaneously verifying the original regions of green and roasted coffee bean samples; this model provided 100% accuracy. Inclusion of this mathematical model for simultaneously verifying the original region of green and roasted coffee beans had powerful distinguishing capability and which will not be influenced by fractionation of hydrogen (2H) and variation of element contents during the roasted process.
This national assessment program was established by the China National Accreditation Service for Conformity Assessment (CNAS) to evaluate the aflatoxin-testing proficiency of a cross-section of Chinese laboratories. The Shan Dong Inspection and Quarantine Bureau of China conducted the assessment according to ISO 13528:2005 (E) and the International Harmonized Protocol for Proficiency Testing. The 77 laboratories that participated in the study had either been previously accredited by CNAS or were candidates for CNAS accreditation. The analytic samples for this testing scheme were prepared from naturally contaminated peanuts and diluted to approximately 10 g/kg for aflatoxin B1 and 18 g/kg for total aflatoxins. The Ss/p test (with a required result of Ss 0.3p) was used to evaluate the homogeneity of the test samples; sample stability was confirmed with a t-test. The performance of each laboratory was designated by a z-score that was calculated using robust statistics. The robust mean of the participants' results in this study was nearly coincident with the median. A modified Horwitz equation was used to determine the standard deviation. The study compared analytic results obtained by 5 different methods: high-performance liquid chromatography (LC), enzyme-linked immunosorbent assay, thin-layer chromatography, fluorometry, and LC with tandem mass spectrometry. A satisfactory performance rating required z-scores between 2 and 2 for the target analytes. Of the 73 laboratories that reported results for aflatoxin B1, 66 (90.4) performed satisfactorily. Of 32 laboratories that reported total aflatoxins (B1 B2 G1 G2), 30 (93.8) performed satisfactorily. Laboratories whose performance ratings were questionable or unsatisfactory were re-evaluated in a second interlaboratory comparison.
Cavity-spawning fishes in several families including the Gobiidae, Cichlidae, Cottidae, Stichaeidae, Pholidae, Cyprinidae, Ictaluridae and Percidae (Moyle & Cech, 1982). Several investigators have studied reproductive behaviour by using artificial cavities to induce spawning in particular species: Baylis (1975) and Barlow et al. (1977) used terra-cotta flower pots for Cichlasoma; D. Hiens and J. Baker (pers. comm.) constructed tile cavities or crevices for Notropis venustus; L. Page (pers. comm.) constructed rock cavities or shelters for Opsopoeodus emiliae; Downhower & Brown (1977) used slate tiles for Cottus bairdi; and McGehee (1 989) used lined PVC pipe for Ophioblennius atlanticus.We developed an artificial nesting cavity to study the reproductive success of the naked goby, Gobiosoma bosci (Lactpede), in the field. The nest-trap not only served as a spawning site, but also acted as a trap to retrieve the eggs and the parent guarding the nest. Nero (1976) used PVC pipe and empty film canisters to induce spawning by G. bosci in the laboratory. However, as his design allowed the retrieval of eggs but not necessarily the adult guarding the eggs, significant relationships involving the reproductive biology and sociobiology of G. bosci could not be determined.Gobiosoma bosci is a cavity-spawner that uses a wide variety of man-made and natural objects for spawning. The male establishes a territory in an appropriate cavity and then guards eggs laid in the nest.Each nest-trap ( Fig. 1) consisted of a piece of PVC pipe 50 or 60 mm in length, 12.5 or 19.0 mm inner diameter, and capped on each end. A 9.1 -mm hole was drilled in the centre of one cap and six 3.3-mm holes were drilled in a ring in the other cap. The larger opening provided an entrance for the gobies; the six smaller holes were designed to enhance water exchange through the nest-trap. Each piece of pipe was cut in half length-wise to facilitate examination of the contents after the nest-trap was opened. Nest-traps were assembled by placing the two halves of each piece of pipe together with a piece of nylon cord between the two halves. The end of the cord was knotted so that it would not slip out when the nest-trap was lifted out of the water. One of each type of end cap was placed on the ends of each piece of pipe. A rubber band was wrapped length-wise around the nest-trap (facilitated by cutting grooves in the caps) and one rubber band was wrapped around the circumference of each end cap, thereby holding the first rubber band in place. This was done to ensure that the nest-trap would not disassemble in the water or when handled. The cord was passed under the rubber band wrapped around the circumference of the end cap with the entrance hole drilled in it. This was done so that the nest-trap, when lifted out of the water, would hang in a vertical position, drain through the small holes in the posterior end cap, and trap the resident inside. The length and diameter of the pipe and the size, position and number of entrances can all be varied.Laboratory test...
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