The invention is directed to methods of generating carbonate in situ in a use solution under an enriched CO2 atmosphere. In another aspect, the invention is directed to methods of cleaning food processing surfaces under an enriched CO2 atmosphere comprising contacting a food processing surface with a cleaning composition comprised of an alkalinity source, a surfactant, and water, monitoring the pH during the wash cycle and adjusting the pH by recirculating a use solution, adding a secondary alkalinity source, or both recirculating a use solution and adding a secondary alkalinity source, to generate carbonate in situ in the use solution. In a particular embodiment of the invention the alkalinity source is an alkali metal carbonate and the secondary alkalinity source is an alkali metal hydroxide.