diff --git a/lib/i18n/backend/base.rb b/lib/i18n/backend/base.rb
index 9f9df168..b78a6af1 100644
--- a/lib/i18n/backend/base.rb
+++ b/lib/i18n/backend/base.rb
@@ -240,7 +240,7 @@ def load_rb(filename)
         def load_yml(filename)
           begin
             if YAML.respond_to?(:unsafe_load_file) # Psych 4.0 way
-              [YAML.unsafe_load_file(filename), false]
+              [YAML.unsafe_load_file(filename, symbolize_names: true, freeze: true), true]
             else
               [YAML.load_file(filename), false]
             end
@@ -255,7 +255,7 @@ def load_yml(filename)
         def load_json(filename)
           begin
             # Use #load_file as a proxy for a version of JSON where symbolize_names and freeze are supported.
-            if JSON.respond_to?(:load_file)
+            if ::JSON.respond_to?(:load_file)
               [::JSON.load_file(filename, symbolize_names: true, freeze: true), true]
             else
               [::JSON.parse(File.read(filename)), false]
diff --git a/test/backend/simple_test.rb b/test/backend/simple_test.rb
index ce9762dc..23de4864 100644
--- a/test/backend/simple_test.rb
+++ b/test/backend/simple_test.rb
@@ -92,15 +92,22 @@ def setup
 
   test "simple load_yml: loads data from a YAML file" do
     data, _ = I18n.backend.send(:load_yml, "#{locales_dir}/en.yml")
-    assert_equal({ 'en' => { 'foo' => { 'bar' => 'baz' } } }, data)
+    if ::YAML.respond_to?(:unsafe_load_file)
+      assert_equal({ :en => { :foo => { :bar => 'baz' } } }, data)
+      assert_predicate data.dig(:en, :foo, :bar), :frozen?
+    else
+      assert_equal({ 'en' => { 'foo' => { 'bar' => 'baz' } } }, data)
+    end
   end
 
   test "simple load_json: loads data from a JSON file" do
     data, _ = I18n.backend.send(:load_json, "#{locales_dir}/en.json")
-    assert_equal({ :en => { :foo => { :bar => 'baz' } } }, data)
 
     if JSON.respond_to?(:load_file)
+      assert_equal({ :en => { :foo => { :bar => 'baz' } } }, data)
       assert_predicate data.dig(:en, :foo, :bar), :frozen?
+    else
+      assert_equal({ 'en' => { 'foo' => { 'bar' => 'baz' } } }, data)
     end
   end