Controlling foodborne pathogens in irrigation water: the effectiveness of zeolite modified with cetrimonium bromide

Abstract

Recurring foodborne outbreaks, attributed to Escherichia coli O157:H7, Salmonella sp., and Listeria monocytogenes, have identified irrigation water as a potential source of contamination, and creating the necessity for safe irrigation water in produce cultivation, as emphasized by the Food Safety Modernization Act (FSMA). In response to this imperative, this study explored the efficacy of surfactant-modified zeolite (SMZ) enhanced with Cetrimonium bromide (CTAB) as a sustainable water purification solution for surface water. The SMZ was assessed to have the capacity to filter contaminated water with high loads of foodborne pathogens. A laboratory study was conducted using a 100 g SMZ column. A liter of phosphate-buffered saline (PBS) was inoculated for each pathogen at 6 log CFU mL-1 concentrations. The study found that SMZ modified with CTAB at a concentration exceeding 20% by weight, indicating the ratio of CTAB to the total mass of the modifying solution, could eliminate >6 log CFU mL-1 of Escherichia coli O157:H7 and Listeria monocytogenes and >2 log of Salmonella sp. Subsequent field testing in strawberry farms demonstrated the system’s effectiveness, displaying significant bacterial reduction when contrasted with unfiltered pond water and sand filtration. The SMZ was able to filter more than 4 log CFU mL-1, from surface irrigation water spiked with a nonpathogenic Escherichia coli strain. The results indicate that the SMZ filtration approach holds promise as a remediation tool to control the risks of foodborne disease outbreaks associated with agricultural water.