diff --git a/app/models/spree/order_contents.rb b/app/models/spree/order_contents.rb
index dc28749e14..2e88c2efe9 100644
--- a/app/models/spree/order_contents.rb
+++ b/app/models/spree/order_contents.rb
@@ -33,7 +33,7 @@ module Spree
 
     def update_cart(params)
       if order.update_attributes(params)
-        order.line_items = order.line_items.select {|li| li.quantity > 0 }
+        discard_empty_line_items
         order.ensure_updated_shipments
         update_order
         true
@@ -44,6 +44,10 @@ module Spree
 
     private
 
+    def discard_empty_line_items
+      order.line_items = order.line_items.select {|li| li.quantity.positive? }
+    end
+
     def update_shipment(shipment)
       shipment.present? ? shipment.update_amounts : order.ensure_updated_shipments
     end