$where .=   " OR ID IN ( SELECT post_id FROM {$wpdb->postmeta}
        WHERE meta_value LIKE '%" . $wp_query->query_vars['s'] . "%'
        AND ( {$wpdb->posts}.ID=post_id AND {$wpdb->posts}.post_status!='inherit'
        AND (  {$wpdb->posts}.post_type='product' ) ) )";