29 research outputs found
A novel L1-Predictor-Corrector method for the numerical solution of the generalized-Caputo type fractional differential equations
No full textS M, Sivalingam/0000-0003-0818-9007; Kumar, Pushpendra/0000-0002-7755-2837This paper proposes a novel L1 -based predictor-corrector method for the fractional differential equations involving generalized-Caputo type derivative. A decomposition scheme is used to obtain the three-point predictor-corrector formula. The error and stability of the proposed method are given in detail. A computer virus and a five-dimensional Hopfield neural network models are solved using the proposed approach.UGC NFOBC Ph.D. Fellowship, India [[202122]-TN13000109]; National Board for Higher Mathematics (NBHM), Department of Atomic Energy, Government of India [02011/18/2023 NBHM (R.P)/ RD II/5952]The first author received the financial support of UGC NFOBC Ph.D. Fellowship, India (Ref. [202122]-TN13000109). V. Govindaraj would like to thank the National Board for Higher Mathematics (NBHM), Department of Atomic Energy, Government of India, for funding the research project (File No. 02011/18/2023 NBHM (R.P)/ R & D II/5952) All authors approved the version of the manuscript to be published
Effect of Ozone and Ultraviolet Irradiation Treatments on Listeria monocytogenes Populations in Chill Brines
No full textThe efficacy of ozone and ultraviolet light, used in combination, to inactivate Listeria monocytogenes in fresh (9% NaCl, 91.86% transmittance at 254 nm) and spent chill brines (20.5% NaCl, 0.01% transmittance at 254 nm) was determined. Preliminary studies were conducted to optimize parameters for the ozonation of "fresh" and "spent" brines. These include diffuser design, comparison of kit to standard methods to measure residual ozone, studying the effect of ozone on uridine absorbance and determining presence of residual listericidal activity post ozonation.
An ozone diffuser was designed using 3/16 inch PVC tubing for the ozonation of brines. The sparger was designed to facilitate better diffusion and its efficiency was tested. The modified sparger diffused 1.44 ppm of ozone after 30 minutes of ozonation and the solution had an excess of 1 ppm in 10 minutes of ozonating fresh brine solution (200ml). Population levels of L. monocytogenes were determined at various time intervals post-ozonation (0, 10, 20, 60 min) to determine the presence of residual listericidal activity. The population post ozonation (0 minutes) was 5.31 Log CFU/ml and was 5.08 Log CFU/ml after a 60 minute interval. Therefore, residual antimicrobial effect was weak. Accuracy of the Vacu-vial Ozone analysis kit was evaluated by comparing the performance of the kit to the standard indigo colorimetric method for measuring residual ozone. The kit was inaccurate in determining residual ozone levels of spent brines and 1% peptone water. Uridine was evaluated as a UV actinometric tool for brine solutions that were ozonated before UV treatment. The absorbance of uridine (A262) decreased after ozonation from 0.1329 to 0.0512 for standard 10 minutes UV exposure duration. Absorbance of uridine was influenced by ozone indicating that the presence of ozone may hamper UV fluence determination accuracy in ozone-treated solutions.
Upon completion of diffuser design and ozone/UV analysis studies, the effect of ozone-UV combination on L. monocytogenes in fresh and spent brines was evaluated. Ozonation, when applied for 5 minutes, caused a 5.29 mean Log reduction while 5 minutes of UV exposure resulted in a 1.09 mean Log reduction of L. monocytogenes cells in fresh brines. Ten minutes of ozonation led to a 7.44 mean Log reduction and 10 minutes of UV radiation caused a 1.95 mean Log reduction of Listeria in fresh brine.
Spent brines required 60 minutes of ozonation for a 4.97 mean Log reduction in L. monocytogenes counts, while 45 minutes resulted in a 4.04 mean Log reduction. Ten minutes of UV exposure of the spent brines resulted in 0.30 mean Log reduction in Listeria cells. A combination of 60 minutes ozonation and 10 minute UV exposure resulted in an excess of 5 log reduction in cell counts. Ozonation did not cause a sufficient increase in the transmittance of the spent brine to aid UV penetration but resulted in apparent color change as indicated by change in L*a*b* values. Ozonation for sufficient time had considerable listericidal activity in fresh brines and spent brines and when combined with UV treatment, is effective reducing L. monocytogenes to undetectable levels in fresh brines.Master of Science in Life Science
Role of airborne soil particulate in transfer of Salmonella spp. to tomato blossoms and consequential fruit contamination
No full textContaminated tomatoes have become a commonly implicated vehicle of Salmonella outbreaks. Exposure of tomatoes to pathogen could occur in the field. Blossom inoculation with Salmonella can result in contaminated fruit but natural routes of blossom contamination are not well known. Salmonellae have been known to survive in agricultural soil. Since dispersal of soil particulate by wind is a common phenomenon, the potential of airborne soil particulate as a vehicle of Salmonella contamination in tomato blossoms was examined.
It was determined that Salmonella enterica serotype Anatum, Baildon, Braenderup, Montevideo, Newport, Javiana had similar survival patterns in both soil and water. At the end of 40 days, populations of Salmonella in soil dropped by 2.59 log CFU/g and 5.11 log CFU/g when enumerated on Tryptic Soy Agar Yeast Extract (TSAYE) and xylose lysine Tergitol 4 (XLT4) agar respectively. Salmonella populations in water reduced by 2.55 log CFU/ml (TSAYE, enumeration) and 2.94 log CFU/ml (XLT4, enumeration). Blossom to fruit formation takes 20-30 days in tomatoes hence the introduction or presence of the pathogen in agricultural soil and water could increase risk of blossom contamination. Also, it was determined that all Salmonella serotypes tested were capable of biofilm production on glass coverslips and quartz particles. Biofilm based attachment of Salmonella to sand might aid in its dispersal.
To visualize transfer of pathogen from soil particulate to blossom in real-time, bioluminescent S. Baildon, S. Braenderup, S. Newport, S. Javiana and S. Anatum were created.Heat shock procedure was developed to improve electrotransformation efficiency in Salmonella. Transformed strains were compared for bioluminescence production and plasmid stability. S. Newport had the best bioluminescence properties but no difference was observed between strains for plasmid stability.
Imaging of soil particulate - S. Newport mixture inoculated blossoms, indicated that the event led to pathogen transfer to blossom. It was also determined that S. Newport â soil particulate contaminated blossoms developed into fruits that were positive for S. Newport. S. Newport presence in blossom, fruit surface and internal tissue indicates that contaminated soil particulate could serve as a vehicle of tomato contamination.Ph. D
Evaluation of Low-Cost Smartphone-Based Infrared Cameras to Assess the Cooling and Refrigerated Storage Temperatures of Fresh Produce
No full textPopulations of pathogens may increase in fresh produce when subjected to temperature abuse. Smartphone-based infrared (SBIR) cameras are potential alternatives for temperature measurements of fresh produce during postharvest handling and storage. This study compared the performance of SBIR cameras (FLIR and Seek) against conventional temperature acquisition devices for evaluating fresh produce’s simulated hydrocooling and storage conditions. First, thermal images of fresh produce were obtained with SBIR cameras and handheld thermal imagers at ~35 °C, ~20 °C, and ~4 °C to simulate outdoor, packinghouse, and refrigerated environments, respectively. Next, fresh produce was incubated at ~42 °C for 20 h and immersed in chilled water for a hydrocooling simulation. Then, boxes containing cooled fresh produce were stored in a walk-in cooler at different heights for three days. FLIR SBIR cameras were more effective at capturing thermal images of fresh produce than Seek SBIR cameras in all evaluated conditions. More importantly, SBIR cameras accurately acquired temperature profiles of fresh produce during simulated hydrocooling and cold storage. Additionally, the accuracy and quality of thermal images obtained with FLIR cameras were better than those obtained with Seek cameras. The study demonstrated that SBIR cameras are practical, easy-to-use, and cost-effective devices to monitor fresh produce’s temperature during postharvest handling and storage
Susceptibility of <i>Salmonella enterica</i> Isolates from Tomato Farm Environments to Fatty Acids Naturally Found on Tomato Fruit
No full textBiofilms: A Community-Based Strategy for Bacterial Persistence and Relevance to Food Safety
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Authorship Pattern and Collaboration in Indian Parasitology Research Output during (2007-2016)
No full textInternational audienceThe study highlights the authorship and research collaboration pattern of the Indian parasitologicalresearch output during 2007-2016. The primary data for the study were retrieved from Scopus database. Thisstudy illustrates various important aspects like – year wise distribution of publications, authorship patterns,author productivity and collaboration. The findings of the study revealed that publications with more than oneauthor dominate in the case of authorship pattern. This study further exposed that the mean values ofCollaboration Index 5.019, Degree of Collaboration 0.966 and Collaborative Coefficient 0.7144. This resultclearly indicates the growing tendency of collaborative research in the subject area of Parasitology
