diff --git a/crontab/crawler.php b/crontab/crawler.php
index 7970c56..fea424b 100644
--- a/crontab/crawler.php
+++ b/crontab/crawler.php
@@ -475,7 +475,7 @@ try {
                                 Filter::pageTitle($title->item(0)->nodeValue),
                                 Filter::pageDescription($metaDescription),
                                 Filter::pageKeywords($metaKeywords),
-                                $queueHostPage->crawlMetaOnly ? null : $content,
+                                $queueHostPage->crawlMetaOnly ? null : Filter::string($content),
                                 time());
 
     // Update manifest registry
diff --git a/library/filter.php b/library/filter.php
index c149c63..1570de3 100644
--- a/library/filter.php
+++ b/library/filter.php
@@ -2,6 +2,11 @@
 
 class Filter {
 
+  static public function string(mixed $data) {
+
+    return (string) $data;
+  }
+
   static public function url(mixed $url) {
 
     $url = (string) $url;