protected static function _strftime($format, $date) {
		$format = strftime($format, $date);
		$encoding = Configure::read('App.encoding');

		if (!empty($encoding) && $encoding === 'UTF-8') {
			$valid = mb_check_encoding($format, $encoding);
			if (!$valid) {
				$format = utf8_encode($format);
			}
		}
		return $format;
	}