3. Results and discussion
3.1. Efficacy of ListShield™ on experimentally contaminated RTE
foods
3.1.1. Lettuce
Application of ListShield™ at a rate of 1 107 PFU/g lettuce
resulted in a 68% (0.5 log) reduction in the number of viable
L. monocytogenes in 5 min of contact time (Fig. 1A), while application
of ListShield™ at 1 108 PFU/g showed a 91% (1.1 log)
reduction of L. monocytogenes within the same time frame. In both
cases, reductions were statistically significant (p < 0.05). While
using the higher ListShield™ application rate resulted in numerically
more effective reduction in the L. monocytogenes counts vs.
lower applications rate (91% vs. 68%), the difference was not statistically
significant. Guenther et al. reported a similar concentration
dependent effect at a comparable level of inoculum (