Evaluation of Novel Filtration System Utilizing Biochar, Zero-Valent Iron, and White Rot Fungi to Inhibit Foodborne Pathogenic Bacteria, Viruses, and Protozoan Parasites

Agricultural water of appropriate microbiological criteria for intended use is crucial for a number of practices, including irrigation, and the possibility of contamination of agricultural water by foodborne pathogens, has raised concerns regarding food safety and the potential for crop contamination, which leads to foodborne illness. To address these concerns, novel water treatment systems are being explored. For example, in this study, a novel combination filtration system that utilizes zero-valent iron, sand, biochar, and white-rot fungi is being assessed. This study was conducted to evaluate the possibility of using a combination of three different filter matrices (biochar, ZVI:sand, and P. chrysosporium inoculated onto woodchips) and their ability to retain various foodborne pathogens, E. coli, Salmonella, Hepatitis A virus, Tulane virus, Cryptosporidium parvum, and Eimeria tenella, to better understand the interactions occurring within these novel filtration systems and filter matrices. Overall, when P. chrysosporium was present, biochar retained more E. coli (2.9-log CFU/mL, p < 0.0001) when compared to ZVI and woodchips, while the filter matrix ZVI with P. chrysosporium present retained more Salmonella (4.5-log CFU/mL, p < 0.0001), HAV (3.3-log copies/rxn, p < 0.0001), C. parvum (2.2-log copies/µL, p < 0.0001), and E. tenella (3.6-log copies/ µL, p = 0.0008). Exploring novel mycofiltration and biofiltration systems that utilize various filter media bridges the gap between conventional technologies and low-cost treatment alternatives for preharvest food safety. Species of P. chrysosporium have exhibited the potential ability to inhibit bacterial species within the environment, miscanthus biochar filtration systems have been shown to effectively remove bacteria from wastewater, and ZVI:sand filtrations are successful at reducing bacteria and protozoan parasites (E. tenella and C. parvum) in water. A combination filtration system utilizing all three of these suggested filter matrices (white-rot fungi, ZVI:sand, and biochar) could improve on-farm mitigation practices and provide a low-cost treatment alternative to promote preharvest food safety or reduce pathogens in agricultural water.