Wordpress: using Excerpts from Advanced Custom Fields on the Search Results Page

functions.php

function excerpt_function($ID, $searchTerms) {
    global $wpdb;
    $thisPost = get_post_meta($ID);
    foreach ($thisPost as $key => $value) {
        if ( false !== stripos($value[0], $searchTerms) ) {
            $found = substr(strip_tags($value[0]), 0, 150);
            echo $found . ' ...';
        }
    }
}

search.php

if (has_excerpt() ){
    the_excerpt();
} else {
    excerpt_function($post->ID, $_GET['s']);
}