diff --git a/core/modules/serialization/serialization.services.yml b/core/modules/serialization/serialization.services.yml
index dca6094..c7bf5ce 100644
--- a/core/modules/serialization/serialization.services.yml
+++ b/core/modules/serialization/serialization.services.yml
@@ -75,10 +75,12 @@ services:
     class: Drupal\serialization\Encoder\JsonEncoder
     tags:
       - { name: encoder, format: json }
+    public: false
   serializer.encoder.xml:
     class: Drupal\serialization\Encoder\XmlEncoder
     tags:
       - { name: encoder, format: xml }
+    public: false
   serializer.entity_resolver:
     class: Drupal\serialization\EntityResolver\ChainEntityResolver
   serializer.entity_resolver.uuid: