Effect of Cleaning and Sanitizing on the Attachment of Pseudomonas fragi to Stainless Steel

The effects of two clean‐in‐place (CIP) procedures on attachment of Pseudomonas fragi ATCC 4913 to a stainless steel surface were studied using scanning electron microscopy (SEM). Under normal CIP conditions those cells that remained in the system did not exhibit attachment fibrils. Under conditions of lowered detergent water temperature and detergent and sanitizer concentrations, those cells that were present after CIP showed attachment fibrils. Organisms remaining after normal CIP were not viable, whereas those present after suboptimum cleaning were. These viable cells produced attachment fibrils within 24 hr at 21°C and 96 hr at 4°C when grown in milk.