MD. The challenge dose of bacteria was applied evenly
onto the top surface of three ca. 240 g portions of smoked salmon.
The samples were covered loosely and the bacteria (1 103 CFU/g)
were allowed to colonize the samples' surfaces for 60 min. All
samples were treated at 0.2 mL/100 g salmon; the control group
was treated with PBS and the treatment groups were treated with
ListShield™ at 9 105 PFU/g or 2 106 PFU/g. The samples were
covered and stored at 4 C for ca. 24 h. From each group, triplicate
25 g samples of smoked salmon were cut and placed into sterile
bags and stomached for approximately 60 s with 225 mL sterile
peptone water. The Oxford plates were incubated at 37 ± 1 C for
48 ± 2 h and the number of viable L. monocytogenes in the samples
was determined as above.