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Isolation and separation of Listeria monocytogenes using bacteriophage P100-modified magnetic particles

Zhou, Yan, Ramasamy, Ramaraja P.
Colloids and surfaces 2019 v.175 pp. 421-427
Listeria monocytogenes, bacteria, bacteriophages, colloids, food matrix, ground beef, magnetic separation, magnetism, particle size, pathogenicity, whole milk
A bacteriophage-assisted magnetic separation method was developed for the isolation of Listeria monocytogenes from complex food matrices. The aim of this study is to understand the effect of phage immobilization methods and the magnetic particle sizes on the phage coupling and infectivity retention of the magnetic particles. In this study, bacteriophage P100-modified magnetic particles (PMMPs) were developed for the separation of L. monocytogenes from food matrices. Three sizes of magnetic particles (MP) (150 nm, 500 nm, and 1 μm) were used for phage immobilization via chemical and physical methods. The coupling ratio of phage was investigated, and the performance of each PMMP complex was evaluated by their L. monocytogenes capture efficiency. When compared to the chemical immobilization method, the physically immobilized PMMP complex achieved a higher capture efficiency initially, with excellent selectivity towards target bacteria. The PMMPs were further tested for selective isolation of L. monocytogenes using real food samples such as ground beef and whole milk.