Be careful with what you mean by "do not show."
Sometimes you want to hide content visually, for design reasons, but you have it in the HTML because it otherwise should be there. People who can't see the visual design for whatever reason would still benefit from that text. So use one of the hidden-offset methods:
height: 0; (sometimes needed)
If a user is accessing a browser's accessibility layer, or is viewing the page without CSS for whatever reason, the content will appear to them. Display: none would hide from many Accessibility Technologies since it tells the browser "this element should not render in any way", so usually the display: none element is not passed on the the accessibility layer.
Use Dave's code if you really want this content to Not Exist, and maybe it's only there because of your back-end setup throwing this content into every page instead of only the pages who need it (it would be more ideal to have your templating system not add this content to the page in the first place, using a bit of template logic).
There is an additional bit of code you could add to this content, HTML5's "hidden" attribute. This tells the user agent (browsers, etc) that "this content should not be on this page".
In your case I would not bother with the ARIA version, in agreement with the article above by Steve Faulkner. Display:none alone will remove the content from AT's in most cases (there are special instances where the content would still show up to screen readers, but this differs per reader and are pretty specific little bugs). That and hidden is more likely to be dangerous than useful, unless you are careful about when this content should appear. If and when you need to remove "hidden", remove it entirely: hidden="false" does not work (and opposite of what aria-hidden does when set to false, which I think was a very bad move among the spec writers... two very similarly named attributes who do very similar things but work completely opposite of each other... bad bad bad).