The Effect of Cold-Pressed Rapeseed Oil and Ampicillin on the Growth of Bacillus cereus

The purpose of this study was to determine if combining a vegetable oil with an antibiotic would show an increased antibacterial effect compared to the antibiotic on its own. Specifically, cold-pressed rapeseed oil (CPRO), a healthier variant of canola oil, was combined with ampicillin against Bacillus cereus, typically resistant to the antibiotic. It was hypothesized that adding 2.5 microliters of CPRO to 5 microliters of ampicillin would show the highest diameter of zone of inhibition of Bacillus cereus by creating a bacteriostatic effect, because the oil contains antimicrobial bioactive compounds. For each of the four treatment groups, 30 antibiotic discs were impregnated with 10 microliters of the solutions/suspensions and placed into the proper quadrant of the agar plates. Ratios of sterile water to ampicillin to oil were as follows; group 1 was 1:0:0, group 2 was 1:1:0, group 3 was 1:2:1, and group 4 was 0:1:1. The agar plates were incubated for 24 hours at 30 degrees Celsius. Treatment group 2 showed the highest mean zone of inhibition at 13.4 mm. Group 3 showed the second lowest zone of inhibition at 9.5 mm. Therefore, the hypothesis was not supported. The ANOVA test showed a p-value of