Display product category in PDF

Hello
I’am using pro version and made my own template using proforma file
All good from here
Then, I want to display main category for each product into the order with this function in my template-functions.php

add_action( 'wpo_wcpdf_before_item_meta', 'wpo_wcpdf_show_product_categories', 10, 3 );
function wpo_wcpdf_show_product_categories ( $document_type, $item, $order ) {
    // get a comma separated list of categories (category links stripped)    
    echo '<div class="product-categories">'.wc_get_product_category_list( $item['product']->get_id() ).'</div>';
 }

But nothing displayed on the pdf file

Any tips or idea ?

Thanks