ABSTRACT
BACKGROUND: Despite improvement in safety of plasma transfusion some virus transmission still remains a problem. So as World Health Organization (WHO) recommends, many countries developed Pathogen Reduction Technologies (PRT) to inactivate pathogens, in plasma components. The Methylene Blue (MB) based methods is one of the most universal one. The purpose of this research was, produce a device that can inactivate viruses in MB environment. MATERIALS AND METHODS: In this interventional study, each Plasma Sample was illuminated by 70Pieces (PCs) of 1 w red Light Emitting Diodes (LEDs) from one side. These LEDs emit light at central wavelength of 627 nm with 20 nm Full Width at Half Maximum (FWHM). Two model viruses Herpes Simplex Virus (HSV) and Vesicular Stomatitis Virus (VSV) were used and Tissue Culture 50% Infection Dose (TCID50) was used to calculate virus Log reduction. Two concentration of MB and 5 different illumination times were used. RESULTS: In 10 µm concentration of MB, HSV had 6.00±0.2 maximum log reduction that obtain after 60 minutes illumination and VSV had 5.50± 0.3 maximum log reduction after 75 minutes illumination. In 1 µM concentration of MB, HSV had 5.20±0.3 maximum log reduction that obtain after 60 minutes illumination and VSV had 4.90± 0.2 maximum log reduction after 75 minutes illumination. CONCLUSION: Results of virus inactivation in this method were similar to other methods (P-value<0.05 in comparison with Spring method, and P-value>0.05 in comparison with Theraflex), and it showed this device could inactivate viruses according to WHO recommendation.
ABSTRACT
BACKGROUND: The aim of this study was to investigate the effect of pulsed ultra-violet (UV) irradiation on inactivation of beer spoilage microorganisms. UV irradiation is nowadays cost effective enough to compete with traditional biological, physical, and chemical treatment technologies and has become an alternative to such methods. MATERIAL AND METHODS: Photoinactivation effects of pulsed UV laser with the wavelengths of 355 and 266 nm, which inactivate typical prokaryotic (Escherichia coli) and eukaryotic (Saccharomyces cerevisiae) microorganisms, were examined with different doses and exposure times. RESULTS: A dose of 100 J/cm(2) of the 355 nm pulsed UV laser was able to reduce about 1 to 2 log (88.75%) of E.coli with the population of 1.6×10(8) colony-forming units (CFU/ml), and 97% of 3.2×10(7), 3×10(6), 5.5×10(5), and 9×10(4) CFU/ml. In the case of 266 nm, more than 99% reduction in E. coli serial dilutions was inactivated, using 10 J/cm(2) with exception of 7×10(4) CFU/ml which was not detected any bacterial growth using 5 J/cm2. In addition, 50, 40, and 20 J/cm(2) energy were used successfully to inactivate S. cerevisiae at the populations of 5.4×10(6), 7×10(5), 5×10(4) and 4×10(3) CFU/ml, respectively. As a result, pulsed UV Laser with 266 nm was strong enough to inactivate a high titer of bacterial and yeast indicator standards suspended in non-alcoholic beer in comparison with 355nm doses. CONCLUSION: Results indicate that pulsed UV technology, in principle, is an attractive alternative to conventional methods for the inactivation of indicator microorganisms and has potential in irradiation of unpasteurized beer.
