PENGARUH PERBEDAAN VARIASI WAKTU RENDAMAN KULIT BUAH NAGA MERAH (Hylocereus polyrhizus) PADA PEMERIKSAAN BAKTERI Escherichia coli SEBAGAI PEWARNA ALTERNATIF PENGGANTI SAFRANIN

Escherichia coli is one of the Gram-negative the main cause of diarrhea. The identification of E. coli can be used by Gram staining using safranin. However, safranin has several limitations such as expensive and carcinogenic. Therefore, alternative dyes from natural compounds such as red dragon fruit peel (Hylocereus polyrhzus) are needed. The purpose of this study was to determine the potency of red dragon fruit peel (Hylocereus polyrhizus) as an alternative dye and the effect of soaking time variations on E. coli bacteria staining. This research was conducted by quasi-experiments, using purposive sampling with a total of 27 samples using safranin as positif control and variations of dragon fruit peel soaking time 24, 36, and 48 hours, respectively. The statistical tests results using Fisher exact obtained significance results p ≤ 0,05 which stated there were difference between Hylocereus polyrhizus and safranin in staining of E. coli bacteria. The present study exhibited the potency of Hylocereus polyrhizus as an alternative dye for E. coli staining, but had not shown better results compared to safranin.