diff --git a/app/controllers/additional_content_boxes_controller.rb b/app/controllers/additional_content_boxes_controller.rb
index 4d3d2d780..960af9c38 100644
--- a/app/controllers/additional_content_boxes_controller.rb
+++ b/app/controllers/additional_content_boxes_controller.rb
@@ -20,6 +20,8 @@ class AdditionalContentBoxesController < ApplicationController
     render "boxes", layout: false
   end
 
+  private
+
   def randomize
     return true unless Rails.env.production?