Merging Feeds into a single RSS Feed

<?php
// Include the SimplePie library, I also use one method from the newsblocks demo to format item descriptions nicely
require_once('./php/simplepie.inc');
require_once('./php/newsblocks.inc.php');

// Try setting header here
header('Content-type:text/xml; charset=utf-8');

// This text file contains a list of valid feed URIs one per line.
$feeds = file('allstarFeeds.txt');

// This array will hold the items we'll be grabbing.
$first_items = array();

// The resulting feed validates use http://feedvalidator.org/ if in doubt

// Let's go through the array, feed by feed, and store the items we want.
foreach ($feeds as $url)
{
    $feed = new SimplePie();
    $feed->set_feed_url($url);
    // Tempted to force feed and see if that returns more data from some of the feeds...
    // Problem in default blogspot feeds isn't going away, just removed them from list of feeds to merge
    $feed->init();

    // How many items per feed should we try to grab?
    $items_per_feed = 1;

    // As long as we're not trying to grab more items than the feed has, go through them one by one and add them to the array.
    for ($x = 0; $x < $feed->get_item_quantity($items_per_feed); $x++)
    {
        $first_items[] = $feed->get_item($x);
    }

    // We're done with this feed, so let's release some memory.
    unset($feed);
}

// We need to sort the items by date with a user-defined sorting function.  Since usort() won't accept "SimplePie::sort_items", we need to wrap it in a new function.
function sort_items($a, $b)
{
    return SimplePie::sort_items($a, $b);
}

// Now we can sort $first_items with our custom sorting function.
usort($first_items, "sort_items");


// Begin the RSS Feed
echo '<?xml version="1.0" encoding="UTF-8" ?>';
?>

<rss version="0.91"> <!-- No need to use RSS version 2.0 -->
<channel>
<title>Merged Feeds</title>
<link>http://news.muschamp.ca</link>
<description>
Merged feeds into a single feed, with one item from each feed, sorted by publish date.
</description>
<language>en-us</language>
<pubDate><?php echo date("D, d M Y H:i:s T"); ?></pubDate>

    <?php
    foreach($first_items as $item)
    {
        $feed = $item->get_feed();
        $feed->xml_dump = true;

        // Added newline characters to make it easier to debug
        print('<item>' . "\n");
                print('<title>' . $feed->get_title() . ' : ' . preg_replace("/&#?[a-z0-9]{2,8};/i", "", $item->get_title()) . '</title>' . "\n");
        print('<link>' . $item->get_permalink() . '</link>' . "\n");
        // 16 corresponds to ENT_XML1
        // The next line functions fine in my experience but perhaps there is a better way to ensure the feed validates
        print('<description>' . htmlspecialchars(newsblocks::cleanup($item->get_description(), 400), 16, "UTF-8") . '</description>'. "\n");
        print('<pubDate>' . $item->get_date("D, d M Y H:i:s T") . '</pubDate>' . "\n");
        print('</item>'. "\n");
    }
    ?>

</channel>
</rss>