Applescript - how to compare (in an if-clause) a bundle identifier?

Something like this script

tell application "Safari"
    activate
end tell
tell application "System Events"
    set frontAppID to bundle identifier of first process whose frontmost is true
end tell

returns "com.apple.Safari"

However, if I try something like

if frontAppID of bundle identifier of first process whose frontmost is "com.apple.safari" then

then it doesn't work. Obviously a bundle identifier cannot be compared with a string. How do I create a bundle identfier object I can use in my comparison?