<?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());