RESUMEN
Shiga toxin producing Escherichia coli (STEC) are common etiological agents of food borne illnesses and outbreaks, most often caused by consuming contaminated beef products, followed by raw vegetables and dairy products. Patients infected with E. coli O157 are more likely hospitalized than patients infected with non-O157 STEC, making E. coli O157 an important target for microbiological interventions. We show that a cocktail of bacteriophages EP75 and EP335 effectively reduces E. coli O157 on beef, romaine lettuce, spinach, and zucchini. Treatment of contaminated beef with either 2 × 107 or 1 × 108 PFU/cm2 of bacteriophage cocktail EP75/EP335 resulted in reductions of 0.8-1.1 log10 CFU/cm2 and 0.9-1.3 log10 CFU/cm2, respectively (P < 0.0001). Similarly, bacteriophage treatments of contaminated romaine lettuce, zucchini, or spinach showed significant (P < 0.05) E. coli O157 reductions of 0.7-1.9 log10 CFU/cm2 (2 × 107 PFU/cm2), and 1.4-2.4 log10 CFU/cm2 (1 × 108 PFU/cm2). An E. coli O157 reduction of 0.9 log10 and 2.0 log10 was observed already 30 min after phage application of 1 × 108 PFU/cm2 on beef and romaine lettuce, respectively. These data show that bacteriophages EP75 and EP335 can be effectively used as a processing aid on beef and vegetables, and thereby can aid industry to reduce the risk of E. coli O157 food poisoning.