scholarly journals Effects of Bacteriophage, Ultraviolet Light, and Organic Acid Applications on STEC O157:H7 and the “Big Six” in Beef Packaged Under Vacuum and Aerobic Conditions

2019 ◽  
Vol 3 (2) ◽  
pp. 140-140
Author(s):  
E. L. Shebs ◽  
F. M. Giotto ◽  
M. J. Lukov ◽  
S. T. Laidler ◽  
A. S. De Mello
Keyword(s):  
Organic Acid ◽  
Ultraviolet Light ◽  
Aerobic Conditions ◽  
Big Six

scholarly journals Effects of Bacteriophage, Ultraviolet Light, and Organic Acid Applications on STEC O157:H7 and the “Big Six” in Beef Packaged Under Vacuum and Aerobic Conditions

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
E. L. Shebs ◽  
F. M. Giotto ◽  
M. J. Lukov ◽  
S. T. Laidler ◽  
A. S. De Mello
Keyword(s):  
Organic Acids ◽  
Ultraviolet Light ◽  
Antimicrobial Effect ◽  
Sodium Chlorite ◽  
Aerobic Conditions ◽  
Log Reduction ◽  
Bacterial Enumeration ◽  
Contrast Analysis ◽  
Antimicrobial Treatments ◽  
And Control

ObjectivesBeef primals produced during high event periods (HEP) can also be affected by STEC contamination requiring microbial assessment. Commonly, primals are retreated with antimicrobials after removal from vacuum bags, then repackaged and tested for STEC. In this study, we evaluated the efficiency of bacteriophage, ultraviolet light, and organic acids on contaminated beef kept under vacuum and aerobic conditions.Materials and MethodsThe effects of antimicrobial interventions Peroxyacetic acid (PAA, 400 PPM), Ultraviolet light (UV, 30 s at 2.5 ± 0.3 cm height), Acidified Sodium Chlorite (ASC, 1200 ppm), and bacteriophage (P, 7 MS phages at 108 PFU/ml) against STEC (O157:H7 and O145, O121, O111, O103, O45, O26) were evaluated on beef. Fresh m. cutaneous trunci was fabricated into 100 cm2 samples (n = 154), which were randomly assigned to 11 treatments including Control, P, UV, ASC, PAA, and combinations P+UV, P+PAA, P+ASC, UV+PAA, UV+ASC, PAA+ASC. Treatments were tested under vacuum and aerobic conditions. Samples were inoculated with a STEC cocktail comprised of 7 strains to yield 3 log CFU/cm2. Samples were vacuumed or overwrapped with oxygen permeable film. Samples were unpackaged and treated with buffered peptone water (BPW, Control) or individual or combined antimicrobial treatments prior to re-packaging. After 1 h at 7°C, samples were swabbed, homogenized in 1 mL of BPW, serially diluted and spread-plated for bacterial enumeration. Data was analyzed using SAS as a completely randomized design.ResultsOverall, treatments including MS phages significantly decreased STEC populations in beef under vacuum and aerobic conditions (P < 0.0001). Under vacuum, individual phage application, combinations between phage and UV, ASC, and PAA plus UV+ASC provided optimal STEC reduction on beef surface. Phage and PAA combination led to the lowest STEC load (1.49 log reduction). When analyzing contrasts, treatments with phage significantly decreased STEC loads when compared to other treatments (P < 0.0001) and control (P < 0.0001). STEC loads recovered from treatments without phage and control were statistically similar at P = 0.32. Under aerobic conditions, individual treatments UV and ASC and combinations including UV+PAA, and PAA+ASC were statistically similar to the control. Inclusion of phage in treatments gradually decreased STEC loads when combined with ASC, PAA, and UV. Phage and UV combination led to the lowest STEC load (1.46 log reduction). Contrast analysis showed that treatments with phage significantly decreased STEC loads when compared to other treatments (P < 0.0001) and control (P < 0.0001). STEC loads recovered from treatments without phage and control were statistically similar at P = 0.07.ConclusionIndividual or combined applications of MS phages on beef surface contaminated with STEC provided optimal antimicrobial effect under vacuum or aerobic conditions. Although organic acids and UV combinations did reduce STEC populations, treatments that included phage yielded the lowest STEC loads. Only phage interventions gave optimal reduction effects under vacuum conditions. Antimicrobial treatments based on individual phage cocktails and their combinations with ASC, UV, and PAA significantly reduce STEC when treating primals produced during HEP.

The Use of Styrenes as Embedding Media for Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 488-489
Author(s):  
Edward D. De-Lamater ◽  
Eric Johnson ◽  
Thad Schoen ◽  
Cecil Whitaker
Keyword(s):  
Electron Microscopy ◽  
Surface Tension ◽  
Ultraviolet Light ◽  
Methyl Ethyl Ketone Peroxide ◽  
Methyl Ethyl ◽  
Styrene Polymerization ◽  
Radical Initiation ◽  
Tertiary Butyl ◽  
Low Viscosity ◽  
Free Radical Initiation

Monomeric styrenes are demonstrated as excellent embedding media for electron microscopy. Monomeric styrene has extremely low viscosity and low surface tension (less than 1) affording extremely rapid penetration into the specimen. Spurr's Medium based on ERL-4206 (J.Ultra. Research 26, 31-43, 1969) is viscous, requiring gradual infiltration with increasing concentrations. Styrenes are soluble in alcohol and acetone thus fitting well into the usual dehydration procedures. Infiltration with styrene may be done directly following complete dehydration without dilution.Monomeric styrenes are usually inhibited from polymerization by a catechol, in this case, tertiary butyl catechol. Styrene polymerization is activated by Methyl Ethyl Ketone peroxide, a liquid, and probably acts by overcoming the inhibition of the catechol, acting as a source of free radical initiation.Polymerization is carried out either by a temperature of 60°C. or under ultraviolet light with wave lengths of 3400-4000 Engstroms; polymerization stops on removal from the ultraviolet light or heat and is therefore controlled by the length of exposure.

Resolution in photoelectron microscopy

1991 ◽  
Vol 49 ◽  
pp. 458-459
Author(s):  
G. F. Rempfer
Keyword(s):  
Electron Microscopy ◽  
Electric Field ◽  
Ultraviolet Light ◽  
Uniform Field ◽  
Virtual Image ◽  
Lens System ◽  
Photoemission Electron Microscopy ◽  
Planar Electrode ◽  
Electron Lens ◽  
Photoemission Electron

In photoelectron microscopy (PEM), also called photoemission electron microscopy (PEEM), the image is formed by electrons which have been liberated from the specimen by ultraviolet light. The electrons are accelerated by an electric field before being imaged by an electron lens system. The specimen is supported on a planar electrode (or the electrode itself may be the specimen), and the accelerating field is applied between the specimen, which serves as the cathode, and an anode. The accelerating field is essentially uniform except for microfields near the surface of the specimen and a diverging field near the anode aperture. The uniform field forms a virtual image of the specimen (virtual specimen) at unit lateral magnification, approximately twice as far from the anode as is the specimen. The diverging field at the anode aperture in turn forms a virtual image of the virtual specimen at magnification 2/3, at a distance from the anode of 4/3 the specimen distance. This demagnified virtual image is the object for the objective stage of the lens system.

Ultrastructural Changes in Three Different Mammalian Cells Following Ultraviolet Laser Irradiation

1972 ◽  
Vol 30 ◽  
pp. 350-351
Author(s):  
K. Shankar Narayan ◽  
Kailash C. Gupta ◽  
Tohru Okigaki
Keyword(s):  
Ultraviolet Light ◽  
Mammalian Cells ◽  
Biological Effects ◽  
Survival Rates ◽  
Chinese Hamster ◽  
Cell Types ◽  
Differential Sensitivity ◽  
Ultrastructural Changes ◽  
Ultraviolet Laser

The biological effects of short-wave ultraviolet light has generally been described in terms of changes in cell growth or survival rates and production of chromosomal aberrations. Ultrastructural changes following exposure of cells to ultraviolet light, particularly at 265 nm, have not been reported.We have developed a means of irradiating populations of cells grown in vitro to a monochromatic ultraviolet laser beam at a wavelength of 265 nm based on the method of Johnson. The cell types studies were: i) WI-38, a human diploid fibroblast; ii) CMP, a human adenocarcinoma cell line; and iii) Don C-II, a Chinese hamster fibroblast cell strain. The cells were exposed either in situ or in suspension to the ultraviolet laser (UVL) beam. Irradiated cell populations were studied either "immediately" or following growth for 1-8 days after irradiation.Differential sensitivity, as measured by survival rates were observed in the three cell types studied. Pattern of ultrastructural changes were also different in the three cell types.

A folding ultraviolet light box

1973 ◽  
Vol 107 (5) ◽  
pp. 716-716 ◽  
Author(s):  
V. H. Witten
Keyword(s):  
Ultraviolet Light

Struktur- und Zusammenhangsanalysen von Emotionen und Persönlichkeitseigenschaften

2001 ◽  
Vol 22 (3) ◽  
pp. 155-172 ◽  
Author(s):  
Peter Becker
Keyword(s):  
Big Five ◽  
Seelische Gesundheit ◽  
Big Six

Zusammenfassung: An einer Stichprobe von 115 Erwachsenen wurden fünf Hypothesen zur Struktur von Emotionen und zu den Beziehungen zwischen Emotionen und Persönlichkeitseigenschaften überprüft. Die umfangreiche Batterie von Messvariablen umfasste: 3 Verfahren zur Messung der Big Five; das Trierer Inventar zur Verhaltenskontrolle zur Messung des Big Six-Faktors “Hedonismus/Spontaneität”; 7 Skalen von Watson und Clark (1992) sowie 12 neu entwickelte Skalen zur differenzierten Erfassung von Emotionen (in Anlehnung an Davitz, 1969 ). Es wurde eine hierarchische Struktur der Emotionen mit den beiden orthogonalen Faktoren 2. Ordnung “negative Affektivität vs. innere Harmonie” und “Aktiviertheit” sowie den vier Faktoren 1. Ordnung “Missbefinden”, “freudige Aktiviertheit”, “Ängstlichkeit” und “Verärgerung” ermittelt. Das von Watson und Tellegen (1985) postulierte Circumplexmodell der Emotionen ließ sich nicht bestätigen. Zwischen den Big Six sowie den beiden Faktoren 2. Ordnung “Seelische Gesundheit” und “Verhaltenskontrolle” und den Emotionen zeigten sich zum Teil enge Zusammenhänge. Diese wurden vor dem Hintergrund zweier theoretischer Grundpositionen diskutiert.

Sign in / Sign up

Export Citation Format

Share Document