diff --git a/includes/index_entity.inc b/includes/index_entity.inc
index a8c72c5..4522d1e 100644
--- a/includes/index_entity.inc
+++ b/includes/index_entity.inc
@@ -538,7 +538,6 @@ class SearchApiIndex extends Entity {
       // all fields regardless of the used bundle.
       $property_info['properties'] = entity_get_all_property_info($wrapper->type());
     }
-
     if (!isset($this->added_properties)) {
       $this->added_properties = array(
         'search_api_language' => array(
@@ -550,7 +549,7 @@ class SearchApiIndex extends Entity {
       );
       // We use the reverse order here so the hierarchy for overwriting property
       // infos is the same as for actually overwriting the properties.
-      foreach (array_reverse($this->getAlterCallbacks()) as $callback) {
+      foreach (array_reverse($this->getAlterCallbacks()) as $key => $callback) {
         $props = $callback->propertyInfo();
         if ($props) {
           $this->added_properties += $props;