Heavy metal concentrations in fish,shellfish and fish products from internal markets of India vis-a-vis international standards

Heavy metals are an important group of chemical contaminants and food is the major vehicle for entry into the system. Fish constitute a major source of heavy metals in food. Concentration of heavy metals in commercially important species of fish, shellfish and fish products from fish markets in and around the Cochin area was evaluated using an atomic absorption spectrometer. The concentration ranges of Cd, Pb, Hg, Cr, As, Zn, Cu, Co, Mn, Ni, and Se in the samples were <0.07–1, <0.07–1.32, <0.05–2.31, <0.05 to 3.65, <0.1–4.14, 0.6 to 165, 0.15 to 24, <0.02 to 0.85, <0.08 to 9.2, <0.032–1.38 and; <0.03–1.35 mg/kg, respectively. The present study showed that different metals were present in the samples at different levels but within the maximum residual levels prescribed by the EU and USFDA and the fish and shellfish from these areas, in general, are safe for human consumption.     

One pot green fabrication of metallic silver nanoscale materials using Crescentia cujete L. and assessment of their bactericidal activity

In this study, the leaf extract of an important medicinal plant Crescentia cujete L. (CC) was employed as a green reducing agent to synthesise highly‐stable C. cujete silver nanoparticles (CCAgNPs). The reduction of Ag⁺ to Ag⁰ nanoparticles was initially observed by a colour change which generates an intense surface plasmon resonance peak at 417 nm using a UV‐Vis spectrophotometer. Various optimisation factors such as temperature, pH, time and the stoichiometric proportion of the reaction mixture were performed, which influence the size, dispersity and synthesis rate of CCAgNPs. In addition, surface chemistry of synthesised CCAgNPs through Fourier transform infrared spectroscopy reveals the reducing/stabilising agent present in the aqueous extract of C. cujete and synthesised CCAgNPs. Transmission electron microscopy analysis features the spherical shape of CCAgNPs with an average size of 39.74 nm. Furthermore, an X‐ray diffraction study confirms that the synthesised CCAgNPs were face‐centred cubic crystalline in nature. The CCAgNPs display tremendous bactericidal activity against human pathogens Bacillus subtilis, Staphylococcus epidermidis, Rhodococcus rhodochrous, Salmonella typhi, Mycobacterium smegmatis, Shigella flexneri and Vibrio cholerae via penetrating into the bacterial cell membrane and causing failure of an internal chain reaction.Inspec keywords: silver, nanoparticles, nanofabrication, surface plasmon resonance, ultraviolet spectra, visible spectra, spectrochemical analysis, surface chemistry, Fourier transform infrared spectra, stoichiometry, transmission electron microscopy, X‐ray diffraction, biomembranes, cellular biophysics, antibacterial activity, nanomedicineOther keywords: one pot green fabrication, metallic silver nanoscale materials, Crescentia cujete L, bactericidal activity, silver nanoparticles, leaf extract, surface plasmon resonance, UV‐vis spectrophotometer, optimisation factors, surface chemistry, stoichiometric proportion, Fourier transform infrared spectroscopy, transmission electron microscopy, X‐ray diffraction, face‐centred cubic crystalline, human pathogens, bacterial cell membrane, Ag     

Identification of haloarchaea during fermentation of Sardinella longiceps for being the starter culture to accelerate fish sauce production

The present study was aimed to improve the value of native species Sardinella longiceps by fermentation method. Throughout the fermentation process, Halophilic archaeal diversity (10³–10⁷ log CFU/g) with their biochemical changes was observed. Overall, 67 archaeal isolates were isolated in various stages of fermentation and its belonging to sixteen genera dominated by Halobacterium (16), Natronobacterium (9), Halococcus (8), Halomicrobium (5), Halorubrum (4) and Haloalkalicoccus (4) which were identified by 16S rRNAgene analysis. During the fish sauce fermentation, Halobacterium sp. S12FS1 was predominant and it has significantly reduced (75%) the maturation time from 12 months into 4 months with an effective biochemical changes and potential protease and lipase enzyme activities. The sensory evaluation of archaeal fermented samples has received higher level (9.1 ± 0.48) of acceptability than control (7.4 ± 0.43). Hence, the implementation of present work will be successful at commercial level and will support directly to fishery products development globally.     

Anti-synchronization of four-wing chaotic systems via sliding mode control

Sliding mode control is an important method used in nonlinear control systems. In robust control systems, the sliding mode control is often adopted due to its inherent advantages of easy realization, fast response and good transient performance as well as its insensitivity to parameter uncertainties and disturbances. In this paper, we derive new results based on the sliding mode control for the anti-synchronization of identical Qi three-dimensional (3D) four-wing chaotic systems (2008) and identical Liu 3D four-wing chaotic systems (2009). The stability results for the anti-synchronization schemes derived in this paper using sliding mode control (SMC) are established using Lyapunov stability theory. Since the Lyapunov exponents are not required for these calculations, the SMC method is very effective and convenient to achieve global chaos anti-synchronization of the identical Qi four-wing chaotic systems and identical Liu four-wing chaotic systems. Numerical simulations are shown to illustrate and validate the synchronization schemes derived in this paper.     

Distribution of Escherichia coli 0157 and Salmonella on hide surfaces, the oral cavity, and in feces of feedlot cattle

To determine the distribution of pathogens on cattle hides at the feedlot, samples were collected from six hide surface locations (back, flank, hock, neck, perineum, and ventrum), the oral cavity, the rectal-anal junction, and the feces of feedlot cattle and subjected to Escherichia coli 0157 detection via culture methods and to Salmonella detection via PCR. E. coli 0157 was isolated from one or more of the sampling locations from 31 (42.5%) of the 73 animals sampled. Location-specific prevalence of E. coli 0157 was 5% for back samples, 5% for flank samples, 12% for hock samples, 7% for neck samples, 12% for perineum samples, 8% for ventrum samples, 1% for oral cavity samples, 4% for rectal-anal junction swabs, and 23% for fecal grab samples. Salmonella was isolated from one or more of these sample locations from 100% (50 of 50 samples) of all animals sampled. Location-specific prevalence of Salmonella was 76% for back samples, 74% for flank samples, 94% for hock samples, 76% for neck samples, 88% for perineum samples, 86% for ventrum samples, 94% for oral cavity samples, 64% for rectal-anal junction swabs, and 50% for fecal grab samples. The sampling locations that maximized the likelihood of finding E. coli 0157 and Salmonella (84 and 96%, respectively) if the animal was positive at one sampling location or more were the hock, perineum, and fecal grab. These data suggest that the use of multiple sample locations is useful when isolating these pathogens from feedlot cattle. Focusing on one sampling location may underestimate the prevalence.