Stx bacteriophages in 68 samples of beef and salad were quantified by real-time quantitative PCR (qPCR). Stx phages from the samples were propagated in Escherichia coli C600, E. coli O157:H7, and Shigella strains and further quantified. Fifty percent of the samples carried infectious Stx phages that were isolated from plaques generated by lysis.
Imamovic, L., & Muniesa, M. (2011). Quantification and Evaluation of Infectivity of Shiga Toxin-Encoding Bacteriophages in Beef and Salad. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 77(10), 3536-3540. https://doi.org/10.1128/AEM.02703-10