use DateTime;

my $line = "14.01.2013 23:55;Messwert1;Messwert2;";
my ($D,$M,$Y,$h,$m,$rest) = $line =~ m/^(\d\d)\.(\d\d)\.(\d\d\d\d)\s(\d\d):(\d\d)(;.+)$/;

my $dt = DateTime->new(
    year      => $Y,
    month     => $M,
    day       => $D,
    hour      => $h,
    minute    => $m,
    second    => 0,
    time_zone => 'Europe/Berlin',
);
$dt->set_time_zone('UTC');

#print $dt->strftime('%d.%m.%Y %H:%M'); # Ausgabe nur mit anderer Zeitzone

$line = $dt->strftime('%d.%m.%Y %H:%M') . $rest;