Hey guys I got an issue in magento when listing products.

$_productCollection = array();
$key = 'product_collection_'.Mage::app()->getRequest()->getRequestUri();    
$_productCollection = Mage::helper('cache')->getDataInCache($key);
if (empty($_productCollection)) {
    $_productCollection=$this->getLoadedProductCollection();
    Mage::helper('cache')->setDataInCache($key,$_productCollection,'front_end_collection');        
}

That's my code, i'm loading the collection and saved in cache, the problem is that I added new products from the admin panel but they are not showing up in the listing.

I have refreshed cache, reindex all the data and checke that the products were in stock. Also check the visibility because i understand that the collection gets just the visible products, am i correct?

I'm using magento enterprise 1.9

I'm new in magento and i'm having troubles understanding how the Collections works, i hope somebody can help me. Thanks