Alkaline cleaners are classified as compounds with pH 7-14.  Proteins are most effectively removed from surfaces by cleaners with a pH of 11 or higher.  An example of a strong alkaline cleaning agent is sodium hydroxide, also called caustic soda.  Although sodium hydroxide (NaOH) can cause corrosion on food contact surfaces such as stainless steel, it is the preferred cleaning agent for protein removal due to its efficacy in dissolving proteins and dispersing/emulsifying food soils.  Silicates are often added to these cleaners to reduce corrosion on metal surfaces.  The mechanism of alkaline cleaning action in proteins follows a three-step process:
# Gel formation:  Upon contact with the alkaline solution, the protein soil swells and forms a removable gel.
# Protein removal:  The protein gel is removed through mass transfer, while the cleaning agent continues to diffuse through the soil, increasing gel formation.
# Decay stage:  The protein gel has been eroded to the point where it is a thin deposit.  Removal at this stage is governed by shear stress forces and mass transfer of the gel.
Hypochlorite is often added to alkaline cleaners to peptize proteins.  Chlorinated cleansers work by oxidizing sulfide crosslinks in proteins.  Cleaning speed and efficiency is improved due to increased diffusion of the cleaner into the soil matrix, now composed of smaller, more soluble proteins.