Effect of the Number of ME Elements on Capture Rate of a Small Number of Pathogens in the Prototype of Phage Filter with a Comparison of Rocking Method

Abstract

Foodborne illness is a frequent public health problem because there is potential for food to be contaminated by pathogens at any point from farms to the dinner tables. Each year, the cost of foodborne illness in the U.S. is enormous. The direct and indirect costs associated with foodborne illness are more than $15.6 billion per year. For rapid detection of foodborne pathogens, Magnetoelastic (ME) biosensor is one of the methods to detect pathogens on food surface and liquids. As the multistate outbreak caused by Romaine lettuce contamination in 2018, current microbiological testing methods, required by Food and Drug Administration (FDA)’s Bacteriological Analytical Manual (BAM), shows shortages. According to the requirement, a new method, named 3D bio-molecular filter, was developed to capture, concentrate, and isolate a small number of pathogens in large volume of liquid streams. The filter consists of ME filter elements, a pair of permanent magnetic plates, and testing glass tube. ME filter elements are magnetically held and arrayed in a testing glass tube. The target pathogen in a large volume of liquid will be capture by ME filter elements when a large volume of liquid passes through. A prototype of a compact edition was developed in this paper to support this method. The device consists of high magnetic plates, which provide uniform high magnetic force to hold ME filter elements, and a square glass tube to pass through the liquid with target pathogen. In this work, E2 phage is immobilized on ME filter elements to capture, concentrate, and isolate Salmonella Typhimurium in processing water. Two different methods to capture Salmonella, rocking method and 3D biomolecular filter method, are compared. The capture rate and effects of the number of ME filter elements on Salmonella capture efficiency will be discussed.