Phage Biocontrol Applications in Food Production and Processing

Bacteriophages, or phages, are one of the most -if not the most -ubiquitous organisms on Earth.Interest in various practical applications of bacteriophages has been gaining momentum recently, with perhaps the most attention (and most regulatory approvals) focused on their use to improve food safety.This approach, termed "phage biocontrol" or "bacteriophage biocontrol," includes both pre-and post-harvest application of phages as well as decontamination of the food contact surfaces in food processing facilities.This review focuses on post-harvest applications of phage biocontrol, currently the most commonly used type of phage mediation.We also briefly describe various commercially available phage preparations and discuss the challenges still facing this novel yet promising approach. Phages are Ancient and Abundant in NatureBacteriophages are the viruses that infect bacteria.They were discovered in 1917 by Félix d'Hérelle in 1917 (Salmond andFineran, 2015;Sulakvelidze et al., 2001), who also coined the term "bacteriophage," derived from "bacteria" and the Greek φαγεῖν (phagein) meaning "to eat" or "to devour" bacteria.Numerous studies, including recent metagenomic surveys, suggest that phages are (i) arguably the oldest microorganisms on this planet that likely originated approximately 3 billion years ago (Brüssow, 2007), and (ii) likely the most ubiquitous organisms on Earth, abundant in all life-supporting environments including all natural untreated foods.To give a few examples: (1) There are an estimated 1.5 × 10 8 phage particles per gram of agricultural soil (Ashelford et al., 2003;Williamson et al., 2003); (2) There are an estimated 7 to 15 × 10 6 phages per mL in fresh water lakes (Mohiuddin and Schellhorn, 2015) and 10 6 to 10 9 particles per mL in sea water (Bergh et al., 1989); (3) Bacteriophages are likely present in 100% of fresh unprocessed foods and have been isolated from various food products such as beef, pork, chicken, fresh produce, dairy, and fermented foods (Aw et al.,