Traffic Verification for Network Anomaly Detection in Sensor Networks

AbstractThe traffic that is being injected to the network is increasing every day. It can be either normal or anomalous. Anomalous traffic is variation in the communication pattern from the normal one and hence anomaly detection is an important procedure in ensuring network resiliency. Probabilistic models can be used to model traffic for anomaly detection. In this paper, we use Gaussian Mixture Model for traffic verification. The traffic is captured and is given to the model to verification. Traffic which obeys the model is normal and those which disobey are anomalies. Analysis shows that the proposed system has better performance in terms of delay, throughput and packet delivery rati

Correlation of cell numbers with catalase activities of pure strains of bacteria

An attempt was made to correlate the catalase production with the actual number of aerobic bacterial cells generating the enzyme: bacteria were obtained from the surface of marine fish. A linear correlation was found between the log of catalase activity and log of bacterial count in single culture

Comparison of media and methods for the detection and enumeration of Clostridium perfringens in seafoods

Three direct plating methods and two most probable number (MPN) procedures were compared for the enumeration of Clostridium perfringens in seafoods the sulfitecycloserine (SC) agar, sulfite-polymyxin-sulfadiazine (SPS) agar, tryptone-sulfite- neomycin (TSN) agar, LS medium MPN procedure and iron milk MPN procedure. Isolates were confirmed as C. perfringens. The two MPN procedures compared very well with the three plating media tested with stock culture of C. perfringens from our laboratory collection and the reference strain NCIB 6125. But in fish samples, the two liquid media were found to be more sensitive and hence the MPN procedure using LS medium for the detection of C. perfringens in seafoods is suggested

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Not AvailableClostridium perfringens has been implicated as the etiological agent in many food poisoning outbreaks. It is a Gram-positive anaerobic spore-forming bacilus. Spores of C. perfringens are widely distributed in soil, sewage, aquatic environments, animal and human intestine, and their presence is usually indicative of sewage contamination. The distribution of C. perfringens in water, sediment and fish/shellfish from brackish water and freshwater environments was investigated. Water, sediment and fish/shellfish samples collected from various locations in three districts of Kerala were screened for the presence of C. perfringens. The study revealed that incidence of C. perfringens was high in sediment samples compared to water samples. In farm sediment samples, occurence of C. perfringens was high (30%), and 22% of the fish/shellfish samples also harboured C. perfringens.Not Availabl

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Not AvailableThe objective of this study was to determine the prevalence of O1, O 139, and non-O1 and non-O 139 Vibrio cholerae, which were associated with fresh and raw seafood samples harvested from Cochin, India waters during 2009-2011. Results from V. cholerae-specific biochemical, molecular, and serological assays identified five El Tor V. cholerae O1 Ogawa strains and 377 non-O1, non-O139 V. cholerae strains from 265 seafood samples. V. cholerae O139 strains were not isolated. Polymerase chain reaction assays confirmed the presence of V. cholerae O1 El Tor bio type in seafood. Antibiotic susceptibility analysis revealed that the V. cholerae O1 strains were pan susceptible to 20 test antibiotics, whereas 26%, 40%, 62%, and 84% of the non-O1, non-O139 V. cholerae strains were resistant to cefpodoxime, ticarcillin, augmentin, and colistin, respectively. Detection of virulence and regulatory genes in V. cholerae associated with seafood revealed the presence of virulence and regulatory genes (i.e., ctx, zot, ace, toxR genes) in V. cholerae O1 strains, nevertheless, presence of ace and toxR genes were detected in non-O1, non-O139 in 9.8 and 91% strains, respectively. In conclusion, the presence of pathogenic V. cholerae in seafood harvested from local Cochin waters warrants the introduction of a post harvest seafood monitoring program, which will lead to a greater understanding of the distribution, abundance, and virulence of diverse pathogenic Vibrio populations that inhabit these different coastal regions so that a risk management program can be established.Not Availabl

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Not AvailableListeria monocytogenes is a very important seafood-borne pathogen, which is capable of forming biofilm on different food-contact surfaces. The efficiency of two commonly used sanitizing agents of seafood-processing industry was checked for inactivation of this pathogen in biofilm formed on glass surface. Treatment with 220 ppm sodium hypochlorite for 5 min and 1000 ppm benzalkonium chloride for 30 seconds could totally inactivate the L. monocytogenes ATCC 19115 in the biofilm. Reduction of the level of this organism to a great extent was possible even at lower concentration in case of both the sanitizers. However, the planktonic cells were found to be highly susceptible. Treatment with 130 ppm sodium hypochlorite for 5 min or 100 ppm benzalkonium chloride for 30 seconds can totally inactivate planktonic cells of L. monocytogenes. During storage at 30 ºC, the L. monocytogenes could be recovered from the biofilm upto 26 days of storage. The concentration of chlorine (50-100 ppm), which is commonly used for disinfection different surfaces of seafood-processing plants, can reduce the level of this pathogen to a great extent. The findings of the present study will be helpful in designing proper guidelines for prevention of transmission of L. monocytogenes through seafood-processing plants.Not Availabl

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Not AvailableThe bacterial flora of black clam (Villorita cyprinoides var. cochinensis ) and water samples collected from three clam harvesting areas in Vembanad lake (Kerala, India) were studied. Samples were examined for total aerobic mesophilic count, psychrotrophic count. Vibrios and indicator bacteria. The mean mesophilic counts were in the range of 5.0-5.7 logu, cfu ml"1 and 5.6-6.4 log|0cfu g1 respectively for water and clam samples. The shellfish collected from Vembanad lake showed faecal contamination at levels which did not conform to legal standards. The densities of enterococci and Clostridium perfringens were higher in clams than in the growing waters indicating bioconcentration of these organisms in clams. The bacterial flora on newly caught clam consisted of a variety of bacteria of which 28% were Gram-positive and 72% were Gram-negative. Vibrio and Aeromonas together formed 46% of the total . mesophilic flora. Vibrio species isolated were V. fluvialis, V. fnrnissi, V. metsdmikovii. Among Aeromoms species, Aeromonas hydrophila, A. veronii biovar. sobria, A. media, A caviae were isolated. The remaining Gram-negative genera in the flora belonged to Acinetobacter, Shewvanella, Moraxella and Pseudomonas. The Gram-positive flora of clam was constituted by genera Bacillus, Micrococcus, Corynebacterium and Arthrobacter. High prevalence of Escherichia coli, faecal Streptococci and C. perfringens in water and clam indicates high degree of faecal pollution of the harvesting areas. The isolation of potentially pathogenic bacteria from clams indicates a risk for health of people consuming and also handling raw seafoodNot Availabl

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Not AvailableClostridium botulinum, an anaerobic Gram positive spore forming bacterium, is a food safety hazard. The distribution of C. botulinum in wild caught and farmed finfish and shellfish in India was investigated. A total of 226 samples of finfish and shellfish were tested. An overall prevalence of 16% was found. The predominant types were type C and D (11%) followed by type B (3%) and type A (1%). Incidence of C. botulinum in wild caught and farmed shellfish was 18% and 23%, respectively. The predominant types were type D (13%) followed by type A (8%) and type C (2%).Not Availabl