Influence of cleaning agent reuse on cleaning effectiveness

The Clean-In-Place (CIP) operation use a pump to move a cleaning solution or water over the surfaces of pipelines or alternative food-contact surfaces. In order to improve the overall efficiency of CIP operations, the reuse of cleaning solutions could reduce the demand for water and for cleaning agents. The objective of this study was to investigate the influence of cleaning agent reuse on effectiveness in removal of residues from a food-contact surface during CIP operation. Based on experimental trials conducted with a bench-scale CIP system, more than 99.95% of protein residues were removed by cleaning agent used for the third time. The effectiveness of removal was reduced to approximately 98% when the cleaning agent was used for the fourth and fifth time. The rate constant for removal of the protein residue decreased with the reusing the cleaning agents over three times. When the reused cleaning agents were evaluated in a pilot-scale CIP system, a reduction in the effectiveness of a 0.05% NaOH cleaning agent was detected during the seventh reuse. A 0.5% NaOH cleaning solution maintained cleaning effectiveness through at least seven uses. The pH, electric conductivity, and active alkali concentration of the cleaning solution were monitored, and were found to decrease with the number of uses. The reduced effectiveness of cleaning agents was attributed to the reduced OH- concentration caused by chemical reactions with food residues. Estimation of reduced operating costs associated with the reuse of cleaning solutions was from $7,920 to $ 2,555 per square meter of fouled surface, or about 67%. In general, the outcomes from the project demonstrate that reuse of cleaning solutions can be effective and reduce costs for CIP operations.