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Effects of intensity and processing time of 254 nm UV irradiation on Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Typhimurium were investigated. Intensities measured at 5.08, 10.1, 15.2, and 20.3 cm from the light source were 1.000, 500, 250, and 150 microW/cm2, respectively. Intensities of 250 or 500 microW/cm2 reduced all suspended(More)
Persistence of Salmonella biofilms within food processing environments is an important source of Salmonella contamination in the food chain. In this study, essential oils of thyme and oregano and their antimicrobial phenolic constituent carvacrol were evaluated for their ability to inhibit biofilm formation and inactivate preformed Salmonella biofilms. A(More)
Catfish skins, intestines, fresh fillets, processing surfaces at different production stages, chiller water and non-food contact surfaces were sampled for Listeria monocytogenes and other Listeria species. Among 315 samples, prevalence of L. monocytogenes, Listeria innocua and a group of Listeria seeligeri-Listeria welshimeri-Listeria ivanovii was 21.6,(More)
Raw channel catfish fillets collected from three processing plants during four time periods were tested for the presence of Listeria species. Listeria monocytogenes was the predominant Listeria species found in these catfish fillets, with 25 to 47% prevalence. Other Listeria species, such as L. welshimeri, L. innocua, L. ivanovii, L. grayi, and L.(More)
A xylose reductase gene (xyl1) of Candida guilliermondii ATCC 20118 was cloned and characterized. The open reading frame of xyl1 contained 954 nucleotides encoding a protein of 317 amino acids with a predicted molecular mass of 36 kDa. The derived amino acid sequence of C. guilliermondii xylose reductase was 70.4% homologous to that of Pichia stipitis. The(More)
An outbreak of classical dengue fever occurred from March to August 1988 in the city of Taxco, Guerrero State, Mexico. Taxco is at an elevation of 1,700 meters above sea level, and this study represents the highest altitude at which an outbreak of dengue has been documented. An investigation was conducted to obtain serologic confirmation of dengue(More)
AIMS To investigate the susceptibility of 221 Listeria spp. (86 Listeria monocytogenes, 41 Listeria innocua and 94 Listeria seeligeri-Listeria welshimeri-Listeria ivanovii) isolated from catfish fillets and processing environment to 15 antibiotics. METHODS AND RESULTS Listeria isolates were analysed by disc-diffusion assay for their resistance to 15(More)
Incidence of Listeria spp. in whole raw catfish, catfish fillets, and processing environments from two catfish processing facilities was determined in August 2008 and August 2009. Thirty-nine (18.4%) of 212 samples collected in August 2008 were positive for Listeria monocytogenes. Prevalences of Listeria species L. innocua and L. seeligeri-L. welshimeri-L.(More)
A group of 37 strains representing all 13 serotypes of Listeria monocytogenes with an initial cell density of 10(7) CFU/ml were analyzed for their heat tolerance at 60°C for 10 min. These L. monocytogenes strains were categorized into three heat tolerance groups: low (<2 log CFU/ml survival), medium (2 to 4 log CFU/ml survival), and high (4 to 6 log CFU/ml(More)
Plant-derived essential oils were tested for their ability to eliminate biofilms of Listeria monocytogenes on polystyrene and stainless steel surfaces. Various concentrations of essential oils were tested with different contact times on biofilms of various ages. Preliminarily screening of nine essential oils and related phenolic compounds in a disk(More)