Food—both raw and ready-to-eat—is an excellent breeding ground for all kinds of microorganisms, including those pathogenic to humans. Bacteria not only spoil food, changing its appearance and taste, but also pose a threat to our health. According to the UN, hundreds of millions of people worldwide suffer from food poisoning every year, of which 4 million die, with 40% of deaths occurring in children under 5 years of age. Among the microorganisms that most often infect people through food are Escherichia coli (~111 million cases of poisoning), Campylobacter spp. (~96 million), non-typhoidal Salmonella enterica (~78 million), and Shigella spp. (~51 million).

Traditionally, methods such as pasteurization and high-pressure treatment are used to improve food safety. However, these methods are not suitable for all foods; for example, they are not suitable for meat, vegetables, fruits, and berries. Radiation treatment also poses problems, as it can alter the organoleptic properties of food and also raises consumer concerns. Chemical disinfection of food products is also losing public favor: chemical disinfectants kill not only pathogenic bacteria but also beneficial microflora in the digestive tract and are harmful to the environment. It is also important to note that foodborne illness outbreaks occur regularly even with the use of all these methods.

In recent years, the use of lytic bacteriophages (phages)* has been explored as a promising method for disinfecting food products. Phage biocontrol (as this method is known) is a natural, "green" technology that helps specifically destroy pathogenic microorganisms without affecting beneficial ones. Research is currently underway in the United States on how treating fresh fruits and berries with bacteriophages affects their nutritional value, as well as the microbiome (gut microflora) of consumers (project W911QY-18-C-0010).

Furthermore, bacteriophages are natural, completely environmentally safe agents. Currently, all phages used in biocontrol products are wild-caught, meaning they have not been genetically modified since their isolation from natural sources. Most phage preparations do not contain any chemicals—only an aqueous phage solution and a low salt concentration. Tests show that bacteriophages do not alter the organoleptic properties of food products. Finally, the cost of using phage preparations for biocontrol in the food industry is relatively low.

Bacteriophage preparations also have some disadvantages that should be considered when using them: bacteriophage preparations must be stored in refrigerators (2-8°C); they cannot be used simultaneously with active chemical disinfectants, which can inactivate bacteriophages; due to their high specificity, phages will not be effective if products are contaminated with multiple pathogens; it is important to use only lytic phages, and not temperate ones, which can transfer DNA fragments between bacteria and, consequently, various undesirable properties.

Already, regulatory agencies in the US and Europe have approved a number of bacteriophage preparations for use in the food industry. They are active against various strains of E. coli, Listeria monocytogenes, Salmonella spp., and Shigella spp. Several other preparations are undergoing trials or are in development.

* Moye ZD, Woolston J and Sulakvelidze A. Bacteriophage Applications for Food Production and Processing Viruses // 2018, 10 (4), 205. https://doi.org/10.3390/v10040205