Whole Gala apples were obtained from a fresh-cut apple producer
in Washington. After being rinsed with tap water, apples
were air dried, weighed, cored, and cut into 8 slices using a manual
food corer/slicer. The average weight per slice was ca. 17 g. Three
slices of apple were not contaminated with bacteria and represent
the untreated, uncontaminated control. The remaining slices were
evenly contaminated on all surfaces, except the skin side, with
1 104 CFU/g apple. The bacteria were allowed to colonize the
apple surfaces for 10 min. All samples were treated at a rate of
0.1 mL/100 g apple and each group contained 9 slices; the control
group was treated with sterile water and the test groups were
treated with either AS, ListShield™ or ListShield™ diluted with AS.
The phage was applied at a rate of 1.1 106 PFU/g. The samples
were covered and stored at 4 C and three slices from each group
were tested at 24 h, 48 h and 72 h post treatment. The three slices
were placed into sterile bags and stomached for 60 s in 10 mL
peptone water. The number of viable L. monocytogenes for each
sample was determined by plating triplicate aliquots (0.1 mL) of the