Purpose: This study is to evaluate foam cleaners and sanitizers on the reduction of pathogens in E. coli, L. monocytogenes, and S. typhimurium based biofilms in simulated industrial food processing plant drain systems.
Methods: Mixed bacterial cultures were inoculated onto sets of carriers and placed in a sterilized drain trap. A diluted tryptic soy broth solution was delivered by a peristaltic, and air pump between drain traps at a volume of 115 ml every hour. The system was active for 96 ±5 h. The developed mature mixed biofilms (> 6.0 Log cfu per carrier) were determined on each control carrier and the drain trap surface. Test replicate carriers and drain surfaces were then foamed with cleaner for a 5-minute contact time. After exposure, individual carriers were added to neutralizing broth, and drain surface swabs were added to neutralizing broth. Serial dilutions were made of each carrier and swab dilutions, then plated onto tryptic soy agar for comparison against controls to determine log reduction.
Results: The completed cleaners so far show a reduction between a 3-5 log. The highest reduction at 5.20 logs came from the heavy chlorinated alkaline product. The second highest reduction at 4.34 logs was seen from a high concentration peroxyacetic acid, hydrogen peroxide product. The lowest reduction shown was at 3.60 logs from a heavy alkaline, quat, hydrogen peroxide blend product.
Significance: The ability to test foaming drain cleaners and sanitizers will provide food processing sanitarians with a functional database of a variety of cleaning technologies that can be used in effective remediation of a contaminated drain system.