diff --git a/app/services/post_service.rb b/app/services/post_service.rb
index 928375e29..4c3d7a6b5 100644
--- a/app/services/post_service.rb
+++ b/app/services/post_service.rb
@@ -46,15 +46,13 @@ class PostService
   end
 
   def mark_comment_reshare_like_notifications_read(post_id)
-    notifications = Notification.where(recipient_id: user.id, target_type: "Post", target_id: post_id, unread: true)
-    notifications.each do |notification|
-      notification.set_read_state(true)
-    end
+    Notification.where(recipient_id: user.id, target_type: "Post", target_id: post_id, unread: true)
+      .update_all(unread: false)
   end
 
   def mark_mention_notifications_read(post_id)
-    mention = find(post_id).mentions.where(person_id: user.person_id).first
-    Notification.where(recipient_id: user.id, target_type: "Mention", target_id: mention.id, unread: true)
-      .first.try(:set_read_state, true) if mention
+    mention_id = Mention.where(post_id: post_id, person_id: user.person_id).pluck(:id)
+    Notification.where(recipient_id: user.id, target_type: "Mention", target_id: mention_id, unread: true)
+      .update_all(unread: false) if mention_id
   end
 end
diff --git a/spec/services/post_service_spec.rb b/spec/services/post_service_spec.rb
index 660e7add4..1d78706b4 100644
--- a/spec/services/post_service_spec.rb
+++ b/spec/services/post_service_spec.rb
@@ -93,6 +93,28 @@ describe PostService do
       }.to change(Notification.where(unread: true), :count).by(-1)
     end
 
+    it "does not change the update_at date/time for post notifications" do
+      notification = Timecop.travel(1.minute.ago) do
+        FactoryGirl.create(:notification, recipient: alice, target: post, unread: true)
+      end
+
+      expect {
+        PostService.new(alice).mark_user_notifications(post.id)
+      }.not_to change { Notification.where(id: notification.id).pluck(:updated_at) }
+    end
+
+    it "does not change the update_at date/time for mention notifications" do
+      status_text = "this is a text mentioning @{Mention User ; #{alice.diaspora_handle}} ... have fun testing!"
+      mention_post = Timecop.travel(1.minute.ago) do
+        bob.post(:status_message, text: status_text, public: true)
+      end
+      mention = mention_post.mentions.where(person_id: alice.person.id).first
+
+      expect {
+        PostService.new(alice).mark_user_notifications(post.id)
+      }.not_to change { Notification.where(target_type: "Mention", target_id: mention.id).pluck(:updated_at) }
+    end
+
     it "does nothing without a user" do
       expect_any_instance_of(PostService).not_to receive(:mark_comment_reshare_like_notifications_read).with(post.id)
       expect_any_instance_of(PostService).not_to receive(:mark_mention_notifications_read).with(post.id)