diff --git a/lib/i18n/backend/simple.rb b/lib/i18n/backend/simple.rb
index 5c7268ef..0dde82d7 100644
--- a/lib/i18n/backend/simple.rb
+++ b/lib/i18n/backend/simple.rb
@@ -35,8 +35,7 @@ def initialized?
         def store_translations(locale, data, options = EMPTY_HASH)
           if I18n.enforce_available_locales &&
             I18n.available_locales_initialized? &&
-            !I18n.available_locales.include?(locale.to_sym) &&
-            !I18n.available_locales.include?(locale.to_s)
+            !I18n.locale_available?(locale)
             return data
           end
           locale = locale.to_sym