2.4. Microbial analysis
After irradiation, each sample (5 g) was blended with 45 mL of sterile saline (0.85%) solution and serially diluted in sterile saline. Each diluent (0.1 mL) was spread on bacterial media, tryptic soy agar (Difco Laboratories) and tryptic soy agar containing 0.6% yeast extract (Difco Laboratories) were used for E. coli O157:H7 and L. monocytogenes respectively. Plates were incubated at 37 °C for 48 h, and microbial counts were expressed as colony forming units per gram (CFU/g).