Effectivity of custard apple’s (Annona squamosa) seed extract in various concentrations on the growth of Escherichia coli

The purposes of this research is to find out: (1) growth differences of Escherichia coli bacteria due to custard apple's ( Annona squamosa ) seed extract in various concentrations, (2) the concentration seed extract of most effective in inhibiting the growth of the bacteria. This research is used true experimental research. The treatment was used 10%, 20%, 30%, 40%, and 50% concentrations seed extract of custard apple's ( Annona squamosa ) toward the averages of diameter the inhibition zone growth of Escherichia coli bacteria. The basic design used is Completely Randomized Design. The population of this research was all E. coli bacteria from the stock culture in Microbiology Laboratory which growth on Nutrient Broth medium, while the samples was E. coli bacteria that given seed extract of custard apple's in various concentrations. MIC (Minimum Inhibitory Concentration) test and MBC (Minimum Bactericidal Concentration) test were also used as supporting data. Moreover, the results of the research that has been done were: (1) there was growth differences of E. coli bacteria due to custard apple's ( Annona squamosa ) seed extract with various concentrations based on hypothesis test with significance different p< 0.05, (2) the concentration of custard apple's ( Annona squamosa ) seed extract which was most effective in inhibiting the growth of E.coli bacteria was 50% concentration. Furthermore, the MIC value was 25%, the MBC was 35%, and Coefficient of Phenol was 125:25.