(99i) Modifying Plastic Surfaces in Dairy Membranes to Act As Antimicrobial Surfaces

Downstream contamination of dairy processes by Listeria monocytogenes (LM) is a serious issue because of the associated mortality rate in immune-compromised individuals. Dairy membranes can be modified to include solid-phase antimicrobials to kill or mitigate growth of LM. The feed spacer mesh of spiral wound dairy membranes has been functionalized with Quaternary Amine Compounds (QACs), a family of broad spectrum antimicrobials that are effective against Gram-positive bacteria. The antimicrobial is covalently bound to the polypropylene surface to avoid leaching into the product stream. Growth curve studies with a surrogate have demonstrated the effectiveness of the surface, and well as the necessary robustness to withstand clean-in-place conditions that will be required when implemented in industry. We have also functionalized the surfaces with polymerized phenolic compounds and comparisons were made with QACs. Preliminary results will also be presented in milk and brine systems.