Bacteriophages reduce Yersinia enterocolitica contamination of food and kitchenware

Abstract

Yersinia enterocolitica, the primary cause of yersiniosis, is one of the most important foodborne pathogens globally and is associated with the consumption of raw contaminated pork. In the current study, four virulent bacteriophages (phages), one of Podoviridae (fHe-Yen3-01) and three of Myoviridae (fHe-Yen9-01, fHe-Yen9-02, and fHe-Yen9-03), capable of infecting Y. enterocolitica were isolated and characterized. fHe-Yen9-01 had the broadest host range (61.3% of strains, 65/106). It demonstrated a latent period of 35 min and a burst size of 33 plaque-forming units/cell, and was found to have a genome of 167,773 bp with 34.79% GC content. To evaluate the effectiveness of phage fHe-Yen9-01 against Y. enterocolitica O:9 strain Ruokola/71, we designed an experimental model of the food market environment. Phage treatment after bacterial inoculation of food samples, including raw pork (4 °C, 72 h), ready-to-eat pork (26 °C, 12 h), and milk (4 °C, 72 h), prevented bacterial growth throughout the experiments, with counts decreasing by 1-3 logs from the original levels of 2-4 × 10 CFU/g or ml. Similarly, when artificially contaminated kitchen utensils, such as wooden and plastic cutting boards and knives, and artificial hands, were treated with phages for 2 h, bacterial growth was effectively inhibited, with counts decreasing by 1-2 logs from the original levels of ca 10 CFU/cm or ml. To the best of our knowledge, this is the first report of the successful application of phages for the control of Y. enterocolitica growth in food and on kitchen utensils.

Yersinia Phages and Food Safety

“…More recently, Jun et al [36] reported the isolation of three additional Myoviruses (fHe-Yen9-01, fHe-Yen9-02, and fHe-Yen9-03) from sewage in Finland capable of infecting Y. enterocolitica. Among these, phage fHe-Yen9-01 was characterized as it had the broadest host range lysing 65 of 106 (61.3%) of Yersinia strains tested and formed plaques on 53/81 (65.4%) of the Y. enterocolitica strains tested, including epidemiologically significant strains of serotype O:3, O:5,27, and O:9.…”

“…Among these, phage fHe-Yen9-01 was characterized as it had the broadest host range lysing 65 of 106 (61.3%) of Yersinia strains tested and formed plaques on 53/81 (65.4%) of the Y. enterocolitica strains tested, including epidemiologically significant strains of serotype O:3, O:5,27, and O:9. The phage genome has a T4-like gene organization and is closely related to the aforementioned Yersinia phages ϕR1-RT and vB_YenM_TG1 [36]. In addition, fHe-Yen9-01 was shown to be stable across a pH range of 5-9 and did not contain genes related to lysogeny or associated with undesirable virulence factors that might preclude their use as biocontrol agents [36].…”

“…The phage genome has a T4-like gene organization and is closely related to the aforementioned Yersinia phages ϕR1-RT and vB_YenM_TG1 [36]. In addition, fHe-Yen9-01 was shown to be stable across a pH range of 5-9 and did not contain genes related to lysogeny or associated with undesirable virulence factors that might preclude their use as biocontrol agents [36].…”

“…At present, studies on the application of Y. enterocolitica phages for food safety are focused on expanding the search for phages with the potential for use in diagnostics [31], or as biocontrol agents to reduce or eliminate this foodborne pathogen from domestic animals or from potentially contaminated foods and fomites [36,64,65].…”

The use of bacteriophages to control and detect pathogens in the dairy industry

“…When the enterococcal phage Q69 was used in a cheese model by Ladero et al (), it resulted in a significantly lower accumulation of tyramine. In another study concerning the zoonotic pathogen Y. enterocolitica , phages were successfully applied to control this pathogen in artificially contaminated milk (Jun et al ). Phages have also been isolated against a variety of other dairy pathogens such as Brucella species, Bacillus subtilis and Campylobacter jejuni , and while no dairy applications have been published to date regarding these genera, the success of phages against the previously mentioned pathogens in dairy products is a good indicator of their potential for biocontrol in dairy products (Parnas et al ; Janež and Loc‐Carrillo ; Krasowska et al ).…”