用ereg阻止特殊字符

elseif (!ereg("^.+@.+\\..+$", $email)) { 
    $msg="• Invalid email: that is not a valid e-mail address."; $email=""; 
}

thats the part of the code im trying to edit it so they cant use ' and = in there email

$email = 'st=ack@overflow.com';

if ( ! filter_var($email, FILTER_VALIDATE_EMAIL) || preg_match('#[\'=]#', $email)) 
{
  echo 'not "valid"';
}