WCM tip #17: Optimize your authoring site for SharePoint search
Cross-site publishing uses SharePoint 2013 Search to publish content. SharePoint 2013 Search indexes the content on authoring sites and makes it available for publishing. During the indexing process, SharePoint 2013 Search indexes not only maps the specific Site Columns to the corresponding Managed Properties but also includes the rendered HTML in the search index. As a result, when your visitors are using search on your website and you’re using Hit Highlighted Summary in search results, there is a chance that they might see the HTML markup of your authoring site. This behavior can be changed in two ways.
First of all you can choose not to use the standard Hit Highlighted Summary but to display a fixed description of each search result. Another solution is to build a user experience specifically for SharePoint 2013 Search and configure a Device Channel mapped to SharePoint 2013 Search User-Agent string. The next time SharePoint will crawl your authoring site, its contents will be displayed using the search-friendly and -safe experience.