Antibacterial Activity Test of Yoghurt Paste Red Fruit (Pandanus conoideus Lam.) Against Escherichia coli

Background: Red fruit (Pandanus conoideus Lam.) contains phenol, terpenoid, alkaloid, tannin, and steroid compounds which function as antibacterial. Yoghurt is a fermented milk product with a manufacturing process by adding two types of lactic acid starter: Lactobacillus bulgaricus and Streptococcus thermophilous. Objective: This study aimed to determine the pH, water content, total solid content, ash content, total lactic acid, and antibacterial activity against Escherichia coli in red fruit (Pandanus conoideus Lam.) paste yoghurt. Method: This study used an experimental approach by making red fruit paste yoghurt in three formulas with different concentrations, namely F1 (10%), F2 (15%), and F3 (20%). An antibacterial activity test was conducted using the disc diffusion method. Results: The results obtained from all tests were the pH in formula 1, 2, and 3, namely 4.7; 4.9, and 4.9; the water content in formula 1, 2, and 3 were 63.33%; 44.66%, and 60.66%; the total solids content of formula 1, 2, and 3 were 36.66%; 55.33%, and 39.33%; the ash content in formula 1, 2, and 3 were 1.40%; 1.66%, and 1.13%; total lactic acid in formula 1, 2, and 3, namely 1.97%; 1.71%, and 2.09%; inhibition zone of antibacterial activity in formula 1, 2, and 3, namely 10.50 mm; 12.47mm, and 13.18mm. Conclusion: In total solids and total lactic acid qualified for Indonesian National Standard (SNI) requirements, while pH, water content, and ash content did not qualify for SNI requirements. Antibacterial activity in red fruit paste yoghurt is a potent category.