Antibiotic-resistant bacteria are an increasing source of concern in all environments in which these drugs have been used. More stringent regulations have led to a slow but sure decrease in antibiotic use in the food industry worldwide, but have also stimulated the search for alternative antibacterial agents. In medicine, the number of people infected with pan-resistant bacteria is driving research to develop new treatments. Within these contexts, studies on the use of bacteriophages in both medicine and the food industry have recently flourished. This renewed interest has coincided with the demonstration that these viruses are involved in geochemical cycles, revolutionizing our vision of their ecological role on our planet. Bacteriophages have co-evolved with bacteria for billions of years and retain the ability to infect bacteria efficiently. They are undoubtedly one of the best potential sources of new solutions for the management of undesirable bacteria.