Four key factors needed for reproducible, validatable cleaning are frequently referred to by the acronym TACT (Time, Action, Chemical, and Temperature).
Time
A reproducible cleaning process requires the same duration each time it occurs with regard to phases such as rinses, chemical solution wash, and draining. The criticality of processing times should be evaluated during process development and validated against the target for cleaning validation.
Action
A reproducible cleaning process requires the same surface action each time it occurs. The flow rate/ pressure can be quantified within a reasonable range, such that the greatest and least flow rate/pressure are evaluated during development studies and validated at the designed flow rate/pressure. During manual cleaning, action is the type of force on the surface ranging from soaking to agitated immersion or the mechanical action of brushing or wiping.
Chemical
Cleaning agents must be selected for efficacy. The reproducible rate kinetics of cleaning chemicals are affected by concentration. Chemical concentration can be qualified by solution concentration formulation and verified by solution conductivity and/or pH when those analytical characteristics are active to the particular detergent chemical. The chemical concentration can be quantified within a reasonable range, such that the greatest and least concentration conditions are evaluated during coupon development studies and validated at the designed detergent concentration.
Temperature
The reproducible rate kinetics of cleaning agents can be affected by temperature. A reproducible cleaning process requires the same temperature each time it occurs. The temperature can be qualified within a reasonable range during coupon studies, such that the highest and lowest temperature conditions are evaluated and validated at the designated operating temperature.
A rugged cleaning process is directly impacted by the amount of cleaning action on the surface of the equipment. CIP systems rely on a combination of spray impingement, cascading flow, and agitated immersion for cleaning whereas manual cleaning generally exerts more scrubbing action on the surface. Selection of the method should take into consideration the size and quantity of the equipment, design of the equipment, and the level of automation available at the facility.
Related: Cleaning Validation Fundamentals
