Microbial analysis
The microbial testing of samples was carried out by the addition of sterile saline ( 9 ml ) to the samples ( 1 g ) , mixing for 2 min using Bag mixer ( Model 400, Interscience, France ) , and diluting the mixture based on 10-fold serial dilution. Each diluent was inoculated to tryptic soy agar (Difco ), and cultured for 48 h at 37 C. The number of colonies produced was counted and expressed as colony-forming units per gram ( CFU/g ).