diff --git a/src/app/code/community/IntegerNet/Solr/Model/Result/Collection.php b/src/app/code/community/IntegerNet/Solr/Model/Result/Collection.php
index bf974b0..14a22b8 100644
--- a/src/app/code/community/IntegerNet/Solr/Model/Result/Collection.php
+++ b/src/app/code/community/IntegerNet/Solr/Model/Result/Collection.php
@@ -143,4 +143,18 @@ protected function _getSolrResult()
 
     public function getLoadedIds ()
     {}
-}
\ No newline at end of file
+
+    /**
+     * Retrieve item id
+     *
+     * @param $item
+     * @return mixed
+     */
+    protected function _getItemId($item)
+    {
+        if($item instanceof Apache_Solr_Document){
+            return $item->getField('product_id')['value'];
+        }
+        return parent::_getItemId($item);
+    }
+}