Figure 4.

Natural microbiota on antibiotic-containing culture plates. To determine if any of the microbiota from the matrices chosen for testing (ground beef, ground pork, ground turkey and spinach) were sufficiently resistant to the antibiotics (spectinomycin, streptomycin, or kanamycin) at the concentrations used in this study, which may interfere with pathogen enumeration, samples were plated onto agar plates containing each of the three antibiotics and photographed after an overnight incubation at 37 °C. Plates shown are representative of the beef and spinach trials before inoculation (“− Pathogen”) and after the inoculation cocktail was added (“+ Pathogen”).