Evaluation of a novel cocktail of six lytic bacteriophages against Shiga toxin-producing Escherichia coli in broth, milk and meat

A team of scientists from Argentina tested the effect of a cocktail of six lytic phages on pathogenic E. coli in meat and milk. The cocktail was found effective against pathogenic E. coli strains in milk and meat especially at room and abusive temperatures. The phage cocktail remained viable at high numbers after challenges in food matrices. The cocktail was effective against DH5α, an enteropathogenic (EPEC) and two Shiga-toxigenic (STEC) E. coli strains. At 4 °C, cell counts were significantly lower (2.2–2.8 log10 CFU/mL) when E. coli strains (∼109 CFU/mL) were challenged against the phage cocktail (∼109 PFU/mL) in Hershey-Mg broth after 24 h. The reductions were higher (3.2–3.4 log10 CFU/mL) after a 48 h exposure for all the strains tested. In milk, the cocktail was highly effective since bacterial counts were below the detection limit (<101 CFU/mL) at 4 °C, while the reductions ranged from 2 to 4 log10 CFU/mL at 24 °C after a 24 h exposure. At 37 °C, DH5α was eliminated within 2 h, and an average cell decrease of 4 log10 CFU/mL was observed for the three pathogenic strains tested. When the assays were performed in meat, the count reduction ranged from 0.5 to 1.0 log10 CFU/mL after 48 h at 4 °C, while a higher cell inactivation was achieved at 24 °C (2.6–4.0 log10 CFU/mL) and 37 °C (3.0–3.8 log10 CFU/mL). @ https://www.sciencedirect.com/science/article/pii/S074000201731184X?dgcid=rss_sd_all