Hektoen Enteric Agar（Granular）

Testing principle:Peptone and beef extract powder serve as basic nutrients in the medium， providing nitrogen sources， carbon sources， and other essential elements required for bacterial cell growth；Sodium Chloride maintains osmotic equilibrium of the system; Bile Salts primarily inhibit the growth of Gram-positive bacteria; Sucrose， Salicin， and Lactose serve as the differential system；Bromothymol Blue and Acid Fuchsin serve as acid-base indicators， enabling the differentiation between carbohydrate-fermenting and non-carbohydrate-fermenting bacteria， the former produce orange-yellow colonies， while the latter produce pale blue-green colonies;Ferric Ammonium Citrate and Sodium Thiosulfate serve as the indicator and substrate for hydrogen sulfide (H?S) production， respectively. Salmonella， which produces H?S but does not ferment carbohydrates， forms colonies with colorless， translucent edges and black centers.