You can replace those 4 substition with one transliteration.

$line =~ tr/\t\n\r"/\x09\x0A\x0D'/;
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And, then, since the date format is fixed, just match up until the period.

$line =~ s{
            (                # start capturing into $1
                [\d|/|\s|:]+ # match digits, 
                             # forward slashes, spaces, 
                             # or colons 1 or more times
            )
            \.               # stop capturing into $1
                             # when you hit a period
            \d\d\d}          # match three more digits 
            {$1}x;           # replace it all w/ $1
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enoch

edit: removed the ig options from the tr because they are not necessary (and not even valid) options.