The Australian Standards AS/NZS 4815 & AS/NZS 4187 recommends the use of mild alkaline detergents (pH 8.0-10.8) for cleaning. Alkaline detergents are recommended because they clean better than neutral or acidic detergents.
Why alkaline detergents clean better:
Alkalinity helps keep soil particles suspended in the cleaning solution, this prevents “clumping” and re-deposition of soil onto the cleaned surface.
Alkalinity converts insoluble fatty acids into their more soluble salts making them easier to wash away.
Alkalinity helps to increase the solubility of proteins.
Alkaline builders help remove calcium and magnesium (soften the water) which improves the performance of surfactants in the detergent.
Alkaline builders help prevent corrosion of metal. Some alkaline ingredients have anti-corrosion properties. Corrosion of steel is at a minimum in mild alkaline solutions (pH 8.5-10) compared to neutral or mild acid solutions where corrosion can be more significant.
Please Note: Its is a common misconception, and not supported by science, that neutral detergents are better for medical and dental instruments and that mildly alkaline detergents are harmful.
Hard Surfaces and Particulates:
Alkaline solutions produce a negative charge on surfaces & suspended soil. Particulates with a negative charge will repel each other, and prevent “clumping” (remember school science? “Like charges repel – opposites attract”.). Instrument surfaces will also be negatively charged and repel the particulates – reducing re-deposition of soils onto the cleaned surfaces.