Abstract: A method and an apparatus for preventing reversion of the color of an indicator dye in a biological indicator is disclosed. The indicator dye changes color if viable microorganisms are present after sterilization, because acidic byproducts are formed when the microorganisms metabolize the growth medium. It has been found that the dye can change color back to the original color after the completion of the sterilization due to leaching or diffusion of basic impurities into the growth medium. The method and the apparatus employ a dual buffer system with one buffer which operates at high pH to moderate pH fluctuations at the start of the sterilization and a second buffer which operates at low pH to minimize pH fluctuations after the sterilization is complete. Less high pH buffer than low pH buffer is used in order to maximize the speed and sensitivity of the biological indicator.

Abstract: A method and an apparatus for preventing reversion of the color of an indicator dye in a biological indicator is disclosed. The indicator dye changes color if viable microorganisms are present after sterilization, because acidic byproducts are formed when the microorganisms metabolize the growth medium. It has been found that the dye can change color back to the original color after the completion of the sterilization due to leaching or diffusion of basic impurities into the growth medium. The method and the apparatus employ a dual buffer system with one buffer which operates at high pH to moderate pH fluctuations at the start of the sterilization and a second buffer which operates at low pH to minimize pH fluctuations after the sterilization is complete. Less high pH buffer than low pH buffer is used in order to maximize the speed and sensitivity of the biological indicator.

Abstract: A method and an apparatus for preventing reversion of the color of an indicator dye in a biological indicator is disclosed. The indicator dye changes color if viable microorganisms are present after sterilization, because acidic byproducts are formed when the microorganisms metabolize the growth medium. It has been found that the dye can change color back to the original color after the completion of the sterilization due to leaching or diffusion of basic impurities into the growth medium. The method and the apparatus employ a dual buffer system with one buffer which operates at high pH to moderate pH fluctuations at the start of the sterilization and a second buffer which operates at low pH to minimize pH fluctuations after the sterilization is complete. Less high pH buffer than low pH buffer is used in order to maximize the speed and sensitivity of the biological indicator.

Abstract: A method and an apparatus for preventing reversion of the color of an indicator dye in a biological indicator is disclosed. The indicator dye changes color if viable microorganisms are present after sterilization, because acidic byproducts are formed when the microorganisms metabolize the growth medium. It has been found that the dye can change color back to the original color after the completion of the sterilization due to leaching or diffusion of basic impurities into the growth medium. The method and the apparatus employ a dual buffer system with one buffer which operates at high pH to moderate pH fluctuations at the start of the sterilization and a second buffer which operates at low pH to minimize pH fluctuations after the sterilization is complete. Less high pH buffer than low pH buffer is used in order to maximize the speed and sensitivity of the biological indicator.

Abstract: A water-based paint confers wet primed adhesion if its binder is a latex whose polymer is a vinyl chloride/acrylic or an all-acrylic containing polymerized therein (based on weight of main monomers) not only 0.3-5% of (meth) acrylic acid but also a fraction of hydroxymethyl diacetone acrylamide (HMDAA) which must be at least 1 % in case of vinyl chloride/acrylics and at least 2% in case of all-acrylics. But, surprisingly, when such a latex is diluted by blending with a vinyl acetate/acrylic latex which by itself does not confer wet primed adhesion, superior wet primed adhesion is obtainable even when the overall level of HMDAA is only 0.65% when the HMDAA latex is an all-acrylic and only 0.40% when the HMDAA latex is a vinyl chloride/acrylic.