抄録
Lytic phages specifically infect and lyse a host bacterial cell, and are being investigated as a treatment for bacterial infections. In addition, attempts are being made to apply phages to reduce contamination of foodborne pathogens in food and to control plant pathogens that damage agricultural produce such as rice and tomatoes. The biggest problem with applying phages in bacterial control is the development of phage resistance in the host bacterial population. This review outlines the mechanism of phage resistance in bacteria, isolation and application of phages controlling foodborne pathogens and food spoilage bacteria, optimization of a phage cocktail, and the combined effects of phages and food additives or natural substances for the control of phage-resistant bacteria. In the isolation of Clostridium perfringens-specific phages and application of a phage cocktail, a combination of four different phages that had the strongest bacteriolytic activity and could suppress the growth of resistant bacterial populations was investigated. In curry roux, viable C. perfringens count was significantly reduced to below the detection limit at 24℃, and the growth of resistant cells was inhibited for up to 48 h. The combination of EDTA and phages was also shown to effectively inhibit the regrowth of phage-resistant populations of Campylobacter, Escherichia coli, Salmonella, and Listeria. The combination of nisin and phages was effective in killing planktonic and biofilm cells of Staphylococcus aureus and delayed the regrowth of phage-resistant populations. Furthermore, the combination of cinnamon oil and phage was effective against Listeria, reducing the viable count of Listeria in milk at 4℃ by more than 4 logs and inhibiting the regrowth of resistant populations. Phages can be produced at low cost, so they provide an economical method for controlling food poisoning bacteria. Phage application is effective in preventing food poisoning, in reducing food waste, extending the shelf life of high-quality processed foods, and is expected to contribute to the achievement of the United Nations Sustainable Development Goals. It is expected that original phage preparations for controlling foodborne pathogens will be approved as food additives in Japan.
