ISOLATION OF BACTERIOPHAGE FROM THE ENVIRONMENT AND CHARACTERIZATION OF ISOLATES FOR POTENTIAL CONTROL OF FOOD BORNE PATHOGENS

Abstract

Bacteriophages, (phages), have been used for the control of pathogens or in phage therapy for almost 100 years. First discovered by Felix d’Herelle in the early 1900s, phages were originally tested as potential agents for the control of diseases in the field of veterinary medicine (17). Phage therapy in these early studies was limited by the inadequate information available on phages at the time. It was not until several decades later when research was done on temperate/virulent life cycles, the narrowness of phage host range, and appropriate purification methods for phage preparations that more effective clinical testing could be conducted. Despite these early limitations, phage therapy has continued with greater interest in Eastern Europe compared with the rather limited work in the United States (4). Phage control has also been evaluated for on-the-farm application to live animals (2) and compost (10) with some demonstrated success in controlling pathogens at the pre- harvest stage of food production. Phage mediated post- harvest biocontrol of food borne pathogens and spoilage microorganisms  has  been explored in  produce  (6, 13, 16), meat (3, 7, 8), and dairy products (5, 9). Given the recent outbreaks   of   food   borne   illness   associated   with fresh produce, and the limited available options for pathogen control in fresh products, phage treatment may represent a viable option for the food industry to reduce the risk of outbreaks in fresh foods. Efforts to utilize phage for pathogen control and therapy are aided by the ubiquity of a diverse population of phages in the environment. Although not generally recognized as a living organism, bacteriophages may be the most abundant element in the micro biome, present at even greater levels than their bacterial hosts (5). Phage can be found at high levels in environments where the host bacteria can be expected to be found replicating, which include water, soil, feces, and food (and at particularly high levels in fermented food). Phages have been detected at levels of up to 107 particles/ml in aquatic environments (18) and 108 viable phage/g of meat product (11). Phage in the environment not only exists in high density, it is also present in great diversity.