Index: django/core/serializers/base.py
===================================================================
--- django/core/serializers/base.py	(revision 5135)
+++ django/core/serializers/base.py	(working copy)
@@ -25,11 +25,12 @@
         """
         Serialize a queryset.
         """
-        self.options = options
-
         self.stream = options.get("stream", StringIO())
         self.selected_fields = options.get("fields")
 
+        del options["stream"]
+        self.options = options
+
         self.start_serialization()
         for obj in queryset:
             self.start_object(obj)