Available evidence suggests that biofilms may play an important role in product contamination such as HEPs at processing plants. Current sanitization studies generally focus on single species pathogen biofilms, but not take into consideration the fact that pathogens are harbored in natural mixed biofilms, which are commonly seen at commercial plants. Further, sanitizer effectiveness can be significantly different due to the interactions between the environmental microorganisms and the pathogens. Our previous study found that certain drain biofilm communities preferentially protected E. coli O157:H7 or Salmonella. We further observed that certain sanitizers, even though not highly effective in deactivating biofilms, reduced overall Salmonella prevalence at certain plants likely due to the environmental microbial community change induced by such treatment that was unfavorable for Salmonella recruitment and survival (ex: bromine in beef spray chill). Therefore the hypothesis of this project is that the different natural biofilm communities at processing plants can either enhance or inhibit Salmonella survival against sanitization and subsequently affect Salmonella prevalence rate. Specific objectives: 1. Evaluate efficacy of commercial sanitizers against Salmonella harbored within environmental mixed biofilms. 2. Measure biofilm forming ability and community structure of environmental biofilms before and after sanitization. 3. Compare environmental microbial communities and Salmonella survival in mixed biofilms before and after sanitization to determine the impact of different sanitizers on controlling Salmonella.