diff --git a/mongodb_field_storage/mongodb_field_storage.module b/mongodb_field_storage/mongodb_field_storage.module
index c295ba9..9f52fa5 100644
--- a/mongodb_field_storage/mongodb_field_storage.module
+++ b/mongodb_field_storage/mongodb_field_storage.module
@@ -281,7 +281,12 @@ class MongodbStorageException extends Exception {}
  * Alter the entity info.
  */
 function mongodb_field_storage_entity_query_alter($query) {
-  $query->executeCallback = 'mongodb_field_storage_query';
+  foreach ($query->fields as $field) {
+    if ($field['storage']['type'] == 'mongodb_field_storage') {
+      $query->executeCallback = 'mongodb_field_storage_query';
+      break;
+    } 
+  } 
 }
 
 /**