Synergistic effect of Nisin with acetic and propionic acids inactivates Bacillus subtilis on meat and potato

B. subtilis can grow, survive, and cause spoilages of meat and potato samples. This situation represents both public health and economic concerns. The present work assessed the inhibitory effects of acetic and propionic acids in combination with Nisin (NS) in preventing meat and potato spoilage caused by B. subtilis. NS inactivated the contaminating microbe at 0.016 mg/ml, acetic and propionic acids at 0.13% v/v and 0.25% v/v respectively. NS (0.002 mg/ml) was combined with acetic acid at 0.065% v/v and propionic acid at 0.125% v/v to delay the rapid proliferation of the B. subtilis inoculated on meat and potato at 105 CFU/g. The samples were treated for 10 min and incubated for 10 day at 37 degrees C. Samples treated with purified water decreased the cell population to 4.21 log CFU/g after 10 min. While acetic, propionic, NS and 0.02N HCL show (3.68, 4.11, 4.05 and 4.15 log decreases). A further significant reduction (p < 0.05) happened after treatments with the combination of NS-acetic and NS-propionic acids (2.26 and 2.38 log CFU/g). DNA retardation analysis shows that neither NS nor acetic or propionic acid target DNA as alternative mechanism of action. At day 10, changes in the color of meat and potato samples treated with NS-organic acids were not significant (p < 0.05) when compared to the control. This is the first report showing the effectiveness of using NS, acetic and propionic acids concoction to control B. subtilis in meat and potato samples.