Cm0069

The bacterial isolation procedure in this study referred to Suardana et al. [4 ]. Ten grams of meat and fecal samples and 10 ml of the water sample were added to 90 ml of buffered peptone water (Conda CAT: 1403.00) 0.1%; then, the meat was mashed using a stomacher, while the feces and water samples were homogenized. Furthermore, as much as, 100 µl of diluted samples were spread on the surface of the EMBA media (Oxoid CM0069) using sterile bent glass, incubated at 37°C for 24 h. The growing colonies that showed a green metallic color with black spots in the middle counted as E. coli colonies and tested positive (+).
Positive results on EMBA media from the three types of samples were cultured on SMAC selective media (Oxoid CM 0813) and were incubated at 37°C for 24 h. Colonies identified as E. coli O157 show characteristics of transparent colonies or colorless colonies, or non-sorbitol fermenting colonies. Colorless colonies were then cultured on brain heart infusion (BHI) media (Conda CAT: 1400.00) (800 µl), incubated at 37°C for 24 h and 200 µl of glycerol was added and stored at −20°C until needed for further examination. Positive bacteria growing on BHI media are characterized by turbidity in the media as shown in Figure-1. In this study, positive control of E. coli O157:H7 was used from the Inter-University Center Universitas Gadjah Mada.

Eosin methyl blue agar (CM0069, OXOID, England) was used to isolate Enterobacteriaceae. The identification of such bacteria was made by the indole test and the Api20 E (bioMérieux, France) gallery [16 ].