Search results for "contamination"
showing 10 items of 916 documents
Sequential window acquisition of all theoretical fragments versus information dependent acquisition for suspected-screening of pharmaceuticals in sed…
2019
The aquatic ecosystems are dynamic environments often affected directly or indirectly by a myriad of anthropogenic contaminants that need to be properly identified. In this study, liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QqTOF-MS) suspected-screening was applied to mussels and riverine sediment both, non-spiked and spiked with a mixture of 32 pharmaceuticals. Three data acquisition methods –sequential window acquisition of all theoretical fragment-ion spectra (SWATH), in fix (FSWATH) and variable (VSWATH) window modes and Information Dependent Acquisition (IDA)– were compared to determine the most suitable acquisition technique. The results obtained in the spike…
Development of a process for the treatment of synthetic wastewater without energy inputs using the salinity gradient of wastewaters and a reverse ele…
2019
Abstract Electrochemical processes are considered very effective methods for the treatment of wastewater contaminated by organics resistant to conventional biological processes and various inorganic pollutants. Large sites that treat wastewaters usually deal with a large number of waters often characterized by different salinity contents, that could be potentially used to provide the energy necessary for the electrochemical remediation. Hence, in this work a reverse electrodialysis (RED) process for the treatment of synthetic wastewaters contaminated by organics, without energy inputs, using the salinity gradient of different wastewaters, was studied, for the first time. It was found that t…
Effect of saliva contamination on cementation of orthodontic brackets using different adhesive systems
2017
Background The enamel condition and the quality of surface are points that need to be considered for achieving optimal efficiency in the treatment with orthodontic brackets. The aim of this study was to assess the immediate bond strength of metallic brackets cemented to dental. Material and Methods Forty human premolars were double-sectioned, placed in PVC matrices and randomly divided into 10 groups (n=8). They received artificial saliva contamination before or after the application of adhesive systems, except for the control groups. The metallic brackets were cemented using two orthodontic cements (Transbond™ Plus Color Change, 3M Unitek e Transbond™ XT Light, 3M Unitek). The specimens we…
Assessment of contamination of <em>Salmonella</em> spp. in imported black pepper and sesame seed and salmonella inactivation by gamma irr…
2021
This study shows the frequency of seeds samples contaminated by Salmonella spp. collected randomly from local markets; on 30 black pepper sample no contaminated sample was found while Salmonella spp. was detected in 3 of 36 (8.3%) analyzed sesame samples; three different serotypes were identified: S. Montevideo, S. Stanleyville e S. Tilene. The efficacy of gamma irradiation to inactivate Salmonella Montevideo in black pepper and sesame irradiated between 1 and 5 kGy was evaluated. 3 kGy is sufficient to reduce of 3-4 log CFU/g; whereas 5 kGy have been need to reduce 5.5-6 log CFU/g for samples of black pepper and sesame. No statistically significant differences were found between black pepp…
Safety Evaluation of Food contact paper and board using Chemical Tests and in vitro Bioassays-The role of known and unknown substances
2010
International audience; In vitro toxicological tests has have been proposed as an approach to complement the chemical safety assessment of food contact materials, particularly those with a complex or unknown chemical composition such as paper and board. An EU 5th framework program project “BIOSAFEPAPER – Application of bioassays for safety assessment of paper and board for food contact” specially focused on the application of biotests to paper and board. The project included both chemical characterization and toxicological testing of a representative number of paper and board extracts prepared according to the proposed end use (wet, fatty and dry food contact). Among the concerns addressed …
Survey of microbial quality of plant-based foods served in restaurants
2013
This study was carried out to evaluate the microbiological quality of plant-based foods obtained from foodservice establishments. The samples included cereals, legumes, fruits and vegetables. According to the European Commission Regulation (No. 2073/2005 and No. 1441/2007) and Spanish microbiological criteria (No. 3484/2000), vegetables were the plant-based dishes where more samples exceed the adopted limits of mesophilic aerobic counts and Enterobacteriaceae. Furthermore, Staphylococcus aureus and Escherichia coli were also found in several vegetable dishes. E. coli and Salmonella spp. were detected in 6.6% and 0.7% of lettuce samples, respectively. However, all the samples were negative f…
Microbial contamination of milk and dairy products from restaurants in Spain
2009
This study was carried out to evaluate the microbiological quality of milk and some dairy products, including 95 lots of warm milk, 95 lots of milk conserved at room temperature, and 75 lots of dairy products collected from restaurants in Spain. According to the European microbiological criteria (92/46/EEC, 93/43/EEC, and Commission Regulation No. 2073/2005), 31% and 35% of the total examined lots exceed the adopted limits of mesophilic aerobic counts and Enterobacteriaceae, respectively. This may be due to incorrect handling of milk and dairy products and inadequate cleaning and sanitization of milk container. Further, 2% of all the lots examined were positive for the presence of Escherich…
Improved Salmonella recovery from moderate to highly polluted waters.
1982
A new enrichment procedure for the recovery of salmonellas from aquatic environments is proposed. It has been tested in a eutrophic lake showing moderate to high faecal contamination levels (the Albufera lake near Valencia, Spain), and in effluents coming into a wastewater treatment plant. The new method consists of the addition of sodium novobiocin to a modification of Rappaport's medium (R10/43°C). The new medium (NR10/43°C) allows a better recovery of salmonellas from water than selenite broth.
Assessment of microbial quality of commercial and home-made tiger-nut beverages
2012
Aims: We aimed to assess the microbiological quality of Spanish commercial tiger-nut beverages as well as home-made samples collected from supermarkets, street vendors, juice bars and ice-cream parlours located in Valencia. Methods and Results: Microbiological analysis of 44 tiger-nut beverages samples were carried out according to International Standard Organization (ISO) norms and published works which included the total viable count, Enterobacteriaceae, Escherichia coli, Staphylococcus aureus, Salmonella, Bacillus cereus, yeasts, moulds, Yersinia enterocolitca, Clostridium perfringens, Vibrio spp. and Listeria monocytogenes. The obtained results indicated that all the commercial sample…
Comparative study onSalmonellaisolation from sewage-contaminated natural waters
1984
Alcaide, E., Martinez, J.P. & Garay, E. 1984. Comparative study on Salmonella isolation from sewage contaminated natural waters. Journal of Applied Bacteriology56, 365–371. A comparative study of five factors influencing the isolation of salmonellas from sewage-contaminated natural waters was carried out. The effect of pre-enrichment in buffered peptone water was compared with single-step enrichment in NR10 broth incubated at 43dC. A modification of NR10 has been compared with the original composition. Bismuth sulphite agar (BSA), Hektoen enteric agar (HE) and brilliant green agar (BGA) have been used as plating media. Other factors considered have been temperature of the water and sampling…