diff --git a/lib/ransack/translate.rb b/lib/ransack/translate.rb
index ffb059f..b231d51 100644
--- a/lib/ransack/translate.rb
+++ b/lib/ransack/translate.rb
@@ -1,6 +1,8 @@
 require 'i18n'
 
-I18n.load_path += Dir[File.join(File.dirname(__FILE__), 'locale', '*.yml')]
+I18n.load_path += Dir[
+  File.join(File.dirname(__FILE__), 'locale'.freeze, '*.yml'.freeze)
+]
 
 module Ransack
   module Translate
@@ -149,7 +151,7 @@ module Ransack
 
     def self.i18n_key(klass)
       if ActiveRecord::VERSION::MAJOR == 3 && ActiveRecord::VERSION::MINOR == 0
-        klass.model_name.i18n_key.to_s.tr('.', '/')
+        klass.model_name.i18n_key.to_s.tr('.'.freeze, '/'.freeze)
       else
         klass.model_name.i18n_key.to_s
       end