Removal of Listeria monocytogenes and Salmonella Typhimurium from Water Using a Filtration System with Surfactated Modified Zeolite

Introduction: Water quality has become one of the principal’s focus of Food Safety control with the Food Safety Modernization Act (FSMA). Some produce farmers use surface water for irrigation that could have a higher bacterial content than allowed by the rule. Therefore, the removal of bacterial from irrigation water at a low cost has become a priority.

Purpose: The purpose of this study was to develop a filtration system with surfactant-modified zeolite (SMZ) to remove Listeria monocytogenes and Salmonella Typhimurium from irrigation water. 

Methods: The SMZ was produced by treating zeolite with a solution of hexadecyltrimethylammonium bromide (HDTMA-Br) at 0, 10, 20, 30% (w/w) and drying at 125°C for 30 minutes. The testing of the SMZ were done using a liter of inoculated water with Listeria monocytogenes and Salmonella Typhimurium, at a concentration of 5 log CFU/ml, which was passed through a column with 20 g of SMZ. The concentration were determinate by plating one ml before and after filtration in Modified Oxford Agar and Xylose Lysine Deoxycholate agar respectively. All analysis were based on three separate experiments with each mean + standard deviation being average of six determinations. 

Results: The SMZ at concentrations of 10, 20, and 30% HDTMA-BR was able to remove 5 log CFU/ml of Listeriamonocytogenes from the water. The control treatment SMZ 0% HDTMA-BR did not remove Listeria monocytogenes from the water. The SMZ at concentration of 0% and 10% HDTMA-BR did not remove Salmonella from the water. The SMZ at 20% and 30% HDTMA-BR was able to filter out 0.4±0.02 log CFU/ml and 1.2±0.10 log CFU/ml of Salmonella from the water, respectively. 

Significance: The SMZ was more effective at removing Listeria monocytogenes than Salmonella Typhimurium from water.