ABSTRACT
We investigated the antimicrobial efficacy of octanoic acid (OA) against Escherichia coli O157:H7 inoculated on the surface of baby spinach and grape tomatoes during simulated washing processes. 3â¯mM OA at 45⯰C achieved >6 log CFU/g reduction from the surface of tomatoes within 2â¯min. However, washing baby spinach with 6â¯mM OA at 5⯰C resulted in <1 log CFU/g reduction, highlighting the role of surface properties in inactivation efficacy. OA significantly (pâ¯<â¯0.05) reduced the risk of cross-contamination during washing of spinach as well as tomatoes. Also, total mold and yeast population on surface of spinach was significantly reduced immediately after OA wash and inhibited during following 14â¯days. Baby spinach and grape tomatoes washed with OA did not cause significant (pâ¯>â¯0.05) difference in color compared to the control and no residual OA was detected in most cases following rinsing of produce in water. OA at the concentrations above 2â¯mM and temperature higher than 25⯰C induced severe membrane damage along with release of ATP and other intracellular constituents resulting in bacterial death. OA can be an attractive natural decontamination agent for washing fresh produce.