<?php
$html = <<<HTML
<html>
 <body>
  <div>
   <p>During the interim there shall be nourishment supplied</p>
  </div>
  <div>
   <p>During the <a href="#">interim</a> there shall be interim nourishment supplied</p>
  </div>
  <div>
   <ul><li>During the interim there shall be nourishment supplied</li></ul>
  </div>
 </body>
</html>
HTML;
$dom = new DOMDocument();
$dom->loadHTML($html);
$xpath = new DOMXPath($dom);
foreach($xpath->query('//*/text()[contains(.,"interim")]') as $n) var_dump($n->getNodePath());