Enforcing "Application/XML" and "Application/JSON" Content-Types in web.config of WCF REST 4.5 Service

I've seen different way of enforcing accepting only:

Application/JSON

Application/XML

in the user land code of a WCF Service. Rather then implement this in code, I want to enforce this in the Web.config xml consumed by IIS.

How do I this?

Currently, my web.config file is:

<?xml version="1.0"?>
<configuration>

  <appSettings>
    <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true" />
  </appSettings>
  <system.web>
    <compilation debug="true" targetFramework="4.5" />
    <httpRuntime targetFramework="4.5"/>
  </system.web>
  <system.serviceModel>
    <services>
      <service name="WcfService1.Service1" behaviorConfiguration="serviceBehavior">
        <endpoint address="" binding="webHttpBinding" contract="WcfService1.IService1" behaviorConfiguration="web"></endpoint>
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior name="serviceBehavior">
          <serviceMetadata httpGetEnabled="true"/>
          <serviceDebug includeExceptionDetailInFaults="false" />
        </behavior>
      </serviceBehaviors>
      <endpointBehaviors>
        <behavior name="web">
          <webHttp automaticFormatSelectionEnabled="true" helpEnabled="true" defaultOutgoingResponseFormat="Json"></webHttp>
        </behavior>
      </endpointBehaviors>
    </behaviors>
    <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
  </system.serviceModel>
  <system.webServer>
    <modules runAllManagedModulesForAllRequests="true"/>
    <!--
        To browse web app root directory during debugging, set the value below to true.
        Set to false before deployment to avoid disclosing web app folder information.
      -->
    <directoryBrowse enabled="true"/>
  </system.webServer>
  <system.web.extensions>
    <scripting>
      <webServices>
        <jsonSerialization maxJsonLength="999999"/>
      </webServices>
    </scripting>
  </system.web.extensions>
</configuration>