Ethanolic Sisyrinchium palmifolium L. Extract as Natural Preservative for Indonesian Tofu Preparation

Tofu is a food product that easily contaminated by microbial due to its water content. Some bacteria usually grow in tofu are Escherichia coli, Bacillus cereus, or Staphylococcus aureus. Preservatives added solve the common storage problem. However, some manufacturers use hazardous substances, such as formalin other chemical preservative. Tiwai onion (Sisyrinchium palmifolium L.) plant grows Borneo and has broad range of antibacterial activity. This study aimed examine activity effectiveness Sisyrinchium extract preservative tofu. was extracted using maceration method with ethanol three times. The concentrated 5% content used for next step. According Clinical Laboratory Standard Institute (CLSI method), test done agar diffusion broth microdilution methods. solution diluted DMSO solvent, tetracycline HCl positive control NaCl 0.9%. Agar 10000 μg/mL 50 μg/mL. an initial concentration 40000 2000 results showed ethanolic minimum inhibitory value 5000 μg / mL. Then, effectivity tested determining Total Plate Count at incubation temperature 37, 25, 4 °C comparison potassium sorbate control. Furthermore, organoleptic evaluation observed 25 °C. effective alternative In conclusion, could serve novel candidate