错误通知:试图获取zend框架中非对象的属性

I使用字符集utf 8，它是错误的：

Notice: Trying to get property of non-object in C:'wamp'www'zend-search-lucene'indexing.php on line 27

这是php:代码

<?php
require_once 'Zend/Search/Lucene.php';
$arr_data = array(0 => array(    "products"       => "Google suggest : pick right search keyword"),
                      1 => array("products"       => "zend framework tutorial | part 9 Zend Auth"));
$lucene_index_path = 'data/';
$index = new Zend_Search_Lucene($lucene_index_path, true);
Zend_Search_Lucene_Analysis_Analyzer::setDefault(new Zend_Search_Lucene_Analysis_Analyzer_Common_Utf8_CaseInsensitive());
foreach($arr_data as $test) {
    //create an cache index doc
    $doc = new Zend_Search_Lucene_Document();
    $doc->addField(Zend_Search_Lucene_Field::Text('products', $test->products, 'UTF-8')); **//LINE 27**
    $index->addDocument($doc);
}
$index->commit();
$index->optimize();