Inactivation of Salmonella and Escherichia coli O157:H7 on sliced and whole tomatoes by allyl isothiocyanate, carvacrol, and cinnamaldehyde in vapor phase.

Little is known about the effectiveness of antimicrobials in the vapor phase for control of pathogens on the surface of fresh produce. We determined the activity of allyl isothiocyanate (AIT), cinnamaldehyde, and carvacrol against Salmonella and Escherichia coli O157:H7 on sliced and whole tomatoes. Samples were treated with various concentrations of antimicrobial in the vapor phase at 4, 10, and 25 degrees C in a closed container. AIT exhibited the highest antimicrobial activity followed by cinnamaldehyde. The lowest level of AIT (8.3 microl/liter of air) inactivated Salmonella on sliced tomatoes by 1.0 and 3.5 log at 4 and 10 degrees C, respectively, in 10 days and by 2.8 log at 25 degrees C in 10 h. This level of AIT inactivated Salmonella on whole tomatoes to the detection limit of <2 log CFU per tomato at 4 and 10 degrees C in 10 days and by 1.3 log CFU per tomato at 25 degrees C in 10 h. AIT also inactivated E. coli O157:H7 on sliced tomatoes by 3.0 log at 4 and 10 degrees C in 10 days, but there was no inactivation at 25 degrees C in 10 h. AIT reduced E. coli O157:H7 on whole tomatoes surface by 3.0 and 1.0 log CFU per tomato at 4 and 10 degrees C, respectively, in 10 days and by 2.0 log CFU per tomato at 25 degrees C in 10 h. Overall, greater inactivation occurred at 10 than at 4 degrees C and on the tomato surface than between slices. Antimicrobials in vapor phase may be useful for controlling pathogens on fresh tomatoes marketed in packages containing enclosed headspace.